王第23巻第3号平成7年9月

内
原

容

著
エクアドルの新大陸型皮膚リーシュマニア症の抗マラリア剤経口投与による治療の試み

一Eduardo A．Gomez Landires，Milorad Andria1
細川 篤，野中 重雄，橋口 義久……………… 151−157
世界各地で分離したコレラ菌・赤痢菌の薬剤感受性の検討
一比嘉

直美，岩永

正明，宇都宮明剛，Thicumporm Kuyyakanond，Noicaseumsy Shitihvong
EddyBagusWashito，ClaudiaToma，山城哲 159−164
熱帯地の健康小児における腸管病原細菌保菌率
一インドネシア，スラバヤ市郊外の小学校における調査研究一一仲宗根昇，岩永正明，Eddy

Bagus

Washito

Lindawati Alimsardjono andThomas Valentinus Widiyatho……一……・…・ 165−167
ドミニカ共和国の農漁村及び都市部における腸管寄生虫感染

一宮田
Ramon

彬，長谷川英男，Mercedes

CastroBello

Baron……………・・…・・…＿＿＿＿．．＿＿

169−176

北タイの谷あいの村におけるハマダラ蚊相とマラリア媒介蚊としての生態学的評価

・・高木正洋，Wawapa Suwonkerd，津田 良夫
Chirasak Kamboonmang，Udom Chipralop
中澤 秀介， 神原 廣二，和田 義人…………
（裏面に続く）177−182一■北タイの山村におけるマラリア媒介蚊の時空的分布………・……一・・WamapaSuwonkerd，高木 正洋，BoonsermAmg−Ung

香港のブユ

183−187

SomsakPrajakwong…一一高岡宏行，DouglasM．Da

2新種の記載esandDavidDudgeon189−196

会報・記録

1995年度日本熱帯医学会第1回理事会記録・

1995年度会員名簿……………

投稿規定（英・和）197
198−220221−222………一

1995年度役員名簿…・…………一・…・…一

223−224

日本熱帯医学会雑誌編集委員名簿……・………

225−226

日本熱帯医学会雑誌発行所

1995年9月15日

印刷

1995年9月15日

発行

日本熱帯医学会
長崎市坂本1丁目12−4
長崎大学熱帯医学研究所内第23巻第3号

TEL

O958−49−7854

FAX

O958−49−7805

編集者

神

印刷所

原

廣

二

㈱昭和堂印刷諌早市長野町1007−2 （⑰854）
君0957−22−6000
本雑誌の刊行にあたりその費用の一部を文部省科学研究費補助金（研究成果公開促進費）によった。

151

J pn. J. Trop. Med. Hyg., Vol. 23, No. 3 (1995) pp. 151‑157

ORAL TREATMENT OF NEW WORLD CUTANEOUS
LEISHMANIASIS WITH ANTI‑MALARIAL DRUGSIN ECUADOR= A PRELIMINARY CLINICAL TRIAL
EDUARDO A. GOMEZ LANDIRES1, MILORAD ANDRIAL2, ATSUSHI HOSOKAWA3,
SHIGEO NoNAKA3 AND YOSHIHISA HASHIGUCH14
Received April 24, 1995/Accepted June 14, 1995

Abstract: The current study was designed to evaluate anti‑1eishmanial activity of mefloquine hydrochloride(MephaquinR) and artesunate (PlasmotriumR) which are currently being used as malarial drugs. A totalof 17 patients (volunteers) with cutaneous leishmaniasis were treated with these drugs in this study. Of thesesubjects, 16 were treated by the oral administration of a total dosage of 1,500mg (1 LactabR each for 6 days)

mefloquine, 4 . 2mg/kg/day for 6 days, and if necessary the dosage was repeated with 3 weeks intervals.

The majority of cutaneous lesions healed within 2 to 3 weeks after the commencement of mefloquine
treatment, showing an average of 3 . 6 weeks of healing times with 100% cure rate. One slowly healing within

8 weeks after the commencement was observed; this case grew worse because of infection with Tunga
penetrans at the late healing phase of leishrnaniasis. The remaining one patient with an ulcer lesion was
treated by the oral administration of a total dosage of 1,200mg (2 LactabR each for 3 days) artesunate, i.
e., 6 . 7mg/kg/day for 3 days, and the same dosage was repeated 2 weeks later. The lesion healed within
6 weeks after the commencement of artesunate treatment. In the present study, all the patients received
mefloquine or artesunate were treated without admission, performing their normal daily activities. No
specified adverse reaction was noticed.

INTRODUCTION
The pentavalent antimonials sodium stibogluconate
and meglumine antimonate remain as the first choice ofdrugs in the clinical treatment of different types ofleishmaniasis, such as cutaneous, mucocutaneous andvisceral forms (Bryceson, 1980; WHO, 1990). Since theintroduction of these antimonials more than 50 years
ago, many investigations have been done in order to findleishmaniasis. In the present study we tried to treat
cutaneous leishmaniasis patients with two types of anti‑

malarial drugs, mefloquine and artesunate, which areclinically being used. The current paper describes theanti‑leishmanial activities of these drugs, based on thedata obtained from clinical trials at endemic areas of

Ecuador.

MATERIALS AND METHODS

more efficient treatment without side effect for the
disease. No satisfactory effective new drugs, however,In the present study, a total of 17 patients withhave been developed, though several important

cutaneous leishmaniasis were examined. They cameadvances have been made (Berman, 1988; Croft, 1988).

from different endemic areas, Zhucay and Manta Real
(Province of Cafiar) , Zapotal (Province of Guayas) ,Muisne (Province of Esmeraldas) and Caluma (Prov‑

There is, therefore, still a need to search for a new drugthat is fully effective and orally applicable for mostclinical forms of Old and New World leishrnaniasis.
To date, trials of search for new drulgs and treat‑ment have been performed in vitro and in vivo using
experimental animals and/or volunteer patients withince of Chimborazo) . Of these subjects, 16 were treatedorqlly with a total dosage of 1,500mg (1 Lactab R eachfor 6 days) mefloquine (Mephaquin R, Mepha Ltd.,
Aesch‑Basle, Switzerland; each Lactab R contains

1) Departamento de Medicina Tropical, Facultad de Medicina, Universidad Catolica Santiago de Guayaquil, P.O.Box 10833 ,Guayaquil, Ecuador
2) Mepha Ltd., Aesch‑Basle, Switzerland
3) Department of Dermatology and the Research Center of Comprehensive Medicine, Faculty of Medicine, Universityof the Ryukyus, Nishihara, Okinawa 903‑01. Japan
4) Department of Parasitology, Kochi Medical School, Nankoku 783 , Kochi, Japan152

mefloquine hydrochloride corresponding to 250mg me‑
floquine base) , i.e., 4.2mg/kg/day for 6 days, and if
necessary the dosage was repeated with 3 weeks inter‑regions (unpublished data).

vals after the end of initial treatment. In patients treated

RESULTS

with mefloquine, 13 out of 16 were male and 3 werefemale, aged from 3 to 81 years. The remaining one

from I to 4 with different size of lesions, ranging frompatient (14 years old male) was treated orally with a
total dasage of 1,200mg (2 Lactab R each for 3 days)
artesunate (Plasmotrium R, Mepha Ltd., each Lactab R
contains artesunate 200mg) , i.e., 6.7mg/kg/day for 3days, and the same dosage was repeated 2 weeks later.
All the subjects were informed of the purpose of thestudy and gave permission for drug administration andrepeated physical examinations. The patients received
treatment during their daily activities without admis‑

The number of cutaneous lesions per person ranged

3 x 3 mm to 30 X 30 mm in diameter (Table) . All thepresent patients had ulcerative lesions; the majority ofthese lesions were located on the exposed body surface,such as forearm, foot and face. The duration time ofinfection varied from one to 12 months (average: 3.6
weeks) at the time of the commencement of mefloquine
treatment. Nine (56.3%) of the 16 patients healed within

3 weeks after the commencement of oral treatment of
mefloquine, showing grade I category (Fig. 2A‑O , andsion. Almost all the volunteers (patients) Iived in moun‑other 6 cases took 4‑6 weeks (grade 2) for healing. Only

tainous and dense forest areas in which no transporta‑tion systems are available (Fig. 1). Their dwellings are

one case (patient No. 3) took 8 weeks for complete
healing, because of Tunga penetrans infection in the
cutaneous lesion which had been at the late phase ofhealing (4 weeks after the commencement of meflo‑

located at very remote areas from our laboratory ofhealth centers in each endemic area. All the volunteers
were in a very poor economic condition. In such a fieldsituation and an ethical consideration, no placebo treat‑ment was performed in the current trial.
A11 the cutaneous leishmaniasis patients treated inthis study were diagnosed by the demonstration ofLeishmania amastigotes in smear specimens from thelesions. Treated patients received a follow‑up physicalexamination every 2 or 3 weeks, and they were recorded
photographically at the same time. When their dermal

quine treatment) . No ineffective case was found in thisstudy using mefloquine; the cure rate showed 100%. In
the present trial of treatment with mefloquine, age or
sex of the patients, number and size of the lesions andduration time of the infection did not show any influenceagainst the efficacy of drug. However, heavy bacterial
infections and other infection such as Tunga penetranswere fully influential for the healing time, especially inlesions located on the lower extremities.

lesions were partially still active in the examination, an

In a patient (14 years old male) treated withadditional administration of the drug was made as
mentioned above. During the treatment, the patientsartesunate (Plasmotrium R) , an ulcer (20 X 17mm) on
the forearm healed within 6 weeks after the commence‑

were asked for the presence of any complaint, such as
vomiting, nausea, diarrhoea, fever and etc.

ment of treatment (Fig.3A‑O and no recurrence wasfound after 5 months (Fig. 3D) . In comparison with

The evaluation of the results of treatment was

mefloquine, however, artesunate showed a slow effec‑

made as described by El‑On et al. (1986) but partiallymodified as follows: D rapidly effective (grade 1), no
parasites detected in cutaneous lesions, followed bytotal healing within I ‑3 weeks after the commencementof treatment; 2) Iess rapidly effective (grade 2), thesame process (no parasites and total healing) occurring
within 4‑6 weeks after the commencement; 3) effective(grade 3) , no parasites detected but healing within 7‑8

tiveness on the healing of the dermal lesion, especially inthe subjects treated were withdrawn from the study

weeks; 4) ineffective (grade 4), parasites still present inbecause of adverse reactions.

the early phase (1 week later) of oral treatment.
All the present patients treated with mefloquine orartesunate lived and worked in a rural and humid areawith hygienically bad conditions. There is no specified
adverse reaction in the patients treated with the drugs,
including skin eruptions or pruritus. Therefore, none oflesions and/or no clinical healing after 9 or 10 weeks ofthe commencement of treatment.
In the present subjects, species of Leishmania are
not identified precisely, but our previous work indicatesthat L. ( Viannia) panamensis is the most frequently

DISCUSSION
For the treatment of most forms of New and Old
World leishmaniasis, pentavalent antimonial compounds

identified organism by zymodeme and serodeme ana‑

are still remain as the drugs of choice. These drugs are

lyses, followed by L. ( V.) guyanensis in the surrounding

given intramuscularly or intravenously, and generally

153

Table. Clinical data on the parasitologically‑positive patients with cutaneous leishmaniasis who

received MephaquinR therapy

Patient Age Sex No. of Size of1

2

Site oflesions

lesions lesions (mrn)

No.

41 d"
16 d

Type of Duration tirne

Times (wks) for
healinglesionsof infection

6

1

35 x 25f orearmulcer

2

20 x 15

nose
cheek

ulcers2M*
12M

30 x 30
10 X 5f oot

ulcers

2M

8

5x5

3

3

8

2

4

12 d"

2

5x5
5x5

f orearm

ulcers

3M

5

5

19 "
81 d"

1

20 >< 10f orearm

ulcer

5

4

20 x 1015 x 1510 x 10
10 X 10f orearm

ulcers3M
2M

6shoulder

4

7

26

3

20 x 2010 x 1010 x 10f orearm

ulcers

IM

4

8

17 d"

1

15 x 10

neck

ulcer

10 x 10

ulcers

IM
5M

2

f ace

IM
8M

2

2M
3M
8M
2M
3M

3

9

10

4

"

22 d"

"

4

5x5
5x5
4x4
1

20 X 10f orearm

ulcer

2

4x4
3x3

f ace

ulcers1

15 x 5f orearm

ulcer

1

4x3

f orearmulcer

30 X 10

f oot

ulcer
ulcer
ulcer

11

3

12

13

13

22

14

22

1

15

31

1

20 X 10f r o nt

16

14

1

34 x 26

f oot

d

d

2

2

3

3
2

6

* M : month.

cause serious adverse reactions, such as renal and liverdisfunctions, nausea, headache and arthragia, in addition
to pain at the injection site. For the treatment of Old

World cutaneous leishmaniasis, El‑On et al. (1986)
reported topical application of paromomycin ointment,
obtaining satisfactory cure rate as good as any currently

used therapy. Recently, the therapy was also used for
New World cutaneous leishmaniasis in Ecuador (Nona‑ka et al., 1992; Krause et al., 1994) and Belize(Weinrauch et al., 1993) , confirming the results reported

by El‑On et al. (1986). However, such a topical treat‑ment using ointment has limitations in its usage even in
cutaneous leishmaniasis cases. Application of ointment

would be only useful for relatively mild and simple

To date, various oral anti‑leishmanial drugs, suchas metronidazole, rifampicin, Ievamizole, ketokonazole,co‑trimoxazole, dapsone and etc., have been used for
different disease forms with variable results. In thepresent study, anti‑malarial drugs, mefloquine andartesunate were selected for clinical trials in thecontinuing search for oral anti‑leishmanial drugs.
These drugs were found to be effective against malarial
parasites in the Old and New World. Mefloquine, a long‑acting quinine analogue is a schizonticide and destroys

the erythrocytic, asexual forms of the Plasmodium
parasites in man, and the mean elimination half‑life of
the drug is culculated as 21.4 days ranging from 15 to 33
days (Desjardins et al., 1979; Schwartz et al., 1980,

lesions which are caused by L. (L.) mexicana groups. It

1982). According to Schwartz et al. (1980, 1982),

is however not feasible for cutaneous disease forms

maximum plasma concentrations are reached 2‑12caused by L. ( V.) braziliensis (Weinrauch et al., 1993)

hours after a single oral dose and plasma concentrations

and mucocutaneous or visceral forms caused by other
Leishmania agents.

approaching I /1 g/ml are present after a dose of 1,
OOOmg of mefloquine. They also showed that similar

154

‑< ?

'

Figure I A dwelling site of inhabitants in an endemic area (Manta Real) surrounded by a dense forest
where the present patients (volunteers) came from.
Figure 2A‑C A cutaneous leishmaniasis lesion located on the lower extremity of a 22 years old female
patient (No. 14) . A, An ulcer (34 x 26mm) with typically elevated border and marked induration aroundthe lesion, before mefloquine treatment. B, After I week of the commencement of oral administration of
meflocluine, the lesion reduced slightly in size and showed a gradual disappearance of the ulcer border andinduration. A marked epidermidalisation was observed on the surface of the lesion. C, After 3 weeks ofmefloquine treatment, the lesion was completely covered by epidermis without induration.
Figure 3A‑D A cutaneous leishmaniasis lesion located on the upper extremity of a 14 years old malepatient. A, A Iesion (20 X 17 mm) showing a typical ulcer border, before artesunate treatment. B, After 2
weeks of the oral administration of artesunate, the lesion showed a marked granulation and reduced ulcer
border. C, The cured lesion completely covered by epidermis without induration, after 6 weeks of artesunate
treatment. D, The lesion (arrow) after 5 months of the treatment, showing a typical scar.

" L;

155

撫﹃

薄

﹃驚．

講

懸

156

maximum concentrations are present in the steady state
after administration of 250mg (1 LactabR) weekly; theconcentration in the erythrocytes is almost twice as
high.

In this study, using mefloquine, almost all cutaneous

lesions healed within 6 weeks after the commencementof treatment showing 100% cure rate, in spite of a
relatively low daily dosage (250mg/day) of the drug
compared with the dosage used in malarial cases. The
precise mode of action of mefloquine against Leish‑
mania has not been determined, although it has been

ACKNOWLEDGEMEN TS
We are grateful to Dr. Alexandra Sari Bravo and

Ms. Gloria Esthela Losa of Subcentro de Salud deZhucay, and to Miss Monica Pauta of Subcentro de
Salud de Manta Real, Province of Cafiar, Ecuador. This
investigation was supported by the Ministry of Educa‑
tion, Science and Culture, Japan (Research grant no.
05041115) and Mepha Ltd., Aesch‑Basle, Switzerland.

REFERENCES

shown that more than 98% of the active substanceagainst Plasmodium schizonts is bound to plasma pro‑

1 ) Berman. J.D. (1988) : Chemotherapy for leishmaniasis:teins (Schwartz et al., 1982) . To some extent, the mode

biochemical mechanisms, clinical efficacy, and futureof action of mefloquine against Leishmania parasites

strategies. Rev. Inf. Dis., 10, 560‑585

might be similar to that found in malarial cases, affect‑2 ) Bryceson, A. (1987) : Therapy in man. In: The leish‑

ing amastigote‑macrophage interactions.
In oral treatment using artesunate, only one casewas experienced in this preliminary trial, suggestingthat the drug might remain as a candidate for future
study. Artesunate, a preparation for the killing oferyihrocytic stage of Plasmodium asexual form, reacts

maniases, Vol. 2, 847‑907, Peters, W. & Killick‑Ken‑drick, R. (eds.), Academic Press, London.
3 ) Croft, S.L. (1988): Recent developments in the chemowith intraparasitic heme in its mechanism of anti‑

Barr.y, K.G. and Canfield, C.J. (1979) : Kinetics of a new

therapy of leishmaniasis. Trends Pharmacol. Sci., 9, 376‑3814 ) Desjardins, R.E., Pamplin, C.L. 3rd, Von Bredow, J.,

malarial action (Meshrick et al., 1991) , but its mode ofantirnalarial mefloquine. Clin. Pharmacol. Therap., 26,

action against Leishmania parasites is still unknown
precisely. According to Jiang et al. (1982), an advan‑

372‑3795 ) E1‑0n, J., Livshin, R., Evan‑Paz, Z., Hamburger, D. andtage of artesunate administration is the speed of onset

Weinrauch, L. (1986) : Topical treatment of cutaneousof action and inhibitory effect on the maturation ofmalarial parasites. On the other hand, in the present

6 ) Jiang,J.B., Li, G.O., Guo, X.B., Kong, Y.C. and Arnold, K.

leishmaniasis. J. Invest. Dermatol., 87, 284‑288

leishmaniasis case, it is likely that the drug has a ten‑(1982) : Antimalarial activity of mefloquine and qingh‑

dency to act slowly as compared with mefloquine, espe‑
cially at the early phase of treatment.

aosu. Lancet ii, 285‑288

7 ) Krause, G. and Kroeger, A. (1994) : Topical treatment of

The current treatment with mefloquine orAmerican cutaneous leishmaniasis with paromomycin

artesunate was done in the subjects who made theirand methylbenzethorium chloride : a clinical study undernormal daily activities without admission. When a simi‑
lar treatment using these drugs was performed in well‑controlled subjects under admission, more rapidly hea‑ling would be found. Furthermore, a rapid healing mightoccur when antibiotics are used as complemental treat‑

field conditions in Ecuador. Trans. Roy. Soc. Trop. Med.

ment to eliminate bacterial infections of cutaneous

Hyg., 88, 92‑94

8 ) Meshnick, S.R., Thomas, A.R., Xu, C.M. and Pan, H.Z.
(199D : Artemisinin (qinghaosu) : the role of int. racel‑lular hemin in its mechanism of antimalarial action.

lesions. With regard to oral administration of the pres‑Mol. Biochem. Parasitol., 49, 181‑190
9 ) Nonaka, S., Gomez, E.A.L., Sud, R.A., Alava, J.J.P.,

ent drugs used, more suitable and effective dosage

Katakura, K. and Hashiguchi, Y. (1992): Topical treat‑should be examined, in addition to their pricise mecha‑
nism (s) of anti‑1eishmanial action.

ment for cutaneous leishmaniasis in Ecuador. In: Studies

In conclusion, the significant efficacy of anti‑malar‑

particular reference to Ecuador. Res. Rep. Ser., 3, 115‑

ial drugs, mefloquine and artesunate against Leishmania
following the oral delivery suggests that the novel anti‑

on New World leishrnaniasis and its transmission, with

124, Hashiguchi, Y. (ed.), Kyowa Printing Co., Kochi,

Japan.

leishmanial activities of these drugs should be inves‑

10) Schwartz, D.E., Eckert, G., Hartmann. D., Weber, B.,

tigated further, and their potential as drugs for various

Richard‑Lenoble, D., Ekue, J.M. and Gentilini, M. (1982)

clinical forms of leishmaniasis including visceral forms

needs more study.

Single dose kinetics of mefloquine in man. Plasma
levels of the uncharged drug and one of its metabolites.

157

Chemotherapy, 28, 70‑84
11) Schwartz, D.E., Weber, W., Richard‑Lenoble, D. andGentilini, M. (1980) : Kinetic studies of mefloquine andone of its metabolites, Ro 21‑5104 in the dog and in man.

Acta Trop., 37, 238‑242
12) Weinrauch, L., Cawich, F., Craig, P., Sosa, J.X. St. andE1‑0n, J. (1993): Topical treatment of New World
cutaneous leishmaniasis in Belize: a clinical study. J.

Am. Acad. Dermatol., 29, 443‑446
13) WHO (1990) : Control of the leishmaniases. Tech. 'Ser., No. 793, 1‑158

159

Jpn. J. Tro p. Med. Hyg., Vol. 23, No. 3 (1995) pp. 159‑164

DRUG SENSITIVITY OF VIBRIO CHOLERAEAND SHIGELLA SPECIES IN THE WORLDMASAAKI IWANAGA1'2, AKIYOSHI UTSUNOMIYA3, THICUMPORN KUYYAKANOND4SITHIVONG5,EDDY BAGUS WASIT06, CLAUDIA TOMAl, AND TETSU YAMASHIR02
NoIKASEUMSYNAOMI HIGA

Received July 20, 1995/Accepted August 16, 1995

Abstract: Recently isolated Vibrio cholerae and Shigella pecies from 6 countries were examined for their drug
sensitivities. The sensitivities of V. cholerae were characterized by a narrow inhibitory concentration ranges without
any resistant strain. However, the sensitivities of Shigella species were variable and mostly resistant to tetracycline
and ampicillin. Japanese isolates of Shigella species were relatively more sensitive to tetracycline and ampicillin than

the isolates from the other countries.

Indonesian isolates of Shigella species were relatively more resistant than those of the other countries, even to the

new antimicrobials such as ofloxacin and cefdinir, and a highly resistant strain against ofloxacin was found.

INTRODUCTION
Cholera and bacillary dysentery (Shigellosis) are
the most notorious illness among diarrheal diseases in
the world. It has generally been said that Shigellaspecies are mostly resistant to traditional antibiotics
such as tetracycline and ampicillin (Carlson et al.,former 3 countries are V. cholerae Ol El Tor and thosefrom the latter 3 countries are V. cholerae 0139 syno‑
nym Bengal. The strains of Shigella species were col‑lected from Bolivia, Dominican Republic, Indonesia,
Laos, Kenya and Japan in total of 191 strains. All
strains were isolated during the period between 1992 and1995.

Drugs examined: Ampicillin (ABPO , Tetracycline1983),while Vibrio cholerae are sensitive to them,although emergence of tetracycline resistant Vibrio(TO, Erythromycin (EM), and Ofloxacin (OFLX)

cholerae has occasionally been reported (Glass et al.,were examined for all isolates. Additionally, Polymyxin

1980; Ramamurthy et al., 1992; Towner et al., 1980;

B (PLB) for V. cholerae and Cefdinir (CFDN) for

Yamamoto et al., 1995) . However, the drug sensitivities

Shigella we.re examined.

of the pathogenic organisms are variable from place toplace where they are isolated, and from time to time of

Sensitivity tests: Minimum inhibitory concentra‑tion (MIO of the drugs were examined by plate dilution
technique. Heart infusion agar plates cdntaining the
drug at the serial 2‑fold concentrations from 0.025pg/ml

isolation. Therefore, the drug sensitivities should inter‑mittently be examined for better understanding of theepidemiological feature. This paper described the drug
sensitivities of V. cholerae and Shigalla species recently

isolated from a variety of places in the world.

MATERIALS AND METHODS
Bacterial strains: V. cholerae were collected fromto 100pg/ml were prepared. The organisms to be
examined were cultured in heart infusion broth overnight and the culture fluids were diluted I : 10 withnormal saline solution for the inoculum (ca. 107/mD.
They were inoculated by using microplanter (Sakuma
Co. MITP#00257) and determination of MIC was madeafter incubation at 37 C for 24 hours.

Argentina, Indonesia, Laos, India, Bangladesh andThailand in total of 159 strains. The isolates from the
1)
2)
3)
4)
5)
6)

Department of Bacteriology, Faculty of Medicine, University of the Ryukyus, Okinawa 903‑01, Japan.
Research Institute of Comprehensive Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa 903‑01, Japan
Department of Bacteriology, Institute of Tropical Medicine, Nagasaki University, Nagasaki 852, Japan.
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
National Institute of Hygiene and Epidemiology, Vientiane, People's Democratic Republic of Laos.
Department of Microbiology, Faculty of Medicine, Airlangga University, Surabaya. Indonesia.

160

RESULT

consumption rate of tetracycline and ampicillin in Japansupposed to be lower than in the other countries. This‑ptration ranges tomay be one of the reasons why Japanese isolates are

inhibit the growth ()f organisins 'vi fe 3.13 t6 12.5pg/ml

relatively sensitive to these drugs. The resistant rate ofof ABPC. 0.2 to 0.4 of TC, 0.4 t6 12,:5 ‑mostly 3.13 to 6.25

Shigella against these traditional antibiotics in the
recent may have reached maximum, because this kind of

V. cholerae: The dru,,conof EM, and less than 0.05 of OFL : E; Xcept PLB, there

was no resistant V. cholerae strain. The sensitivity
pattern was characterized by a narrow inhibitory con‑centration ranges of each drug. There was no variabil‑
ity depending on the place of isolation (Table 1). V.
cholerae 0139 were resistant to PLB Iike V. cholerae Ol

El Tor with the MICs more th: an '25 pg/ml, mostly

100pg/ml. 'Shigella species: Being diffre* nt from V. cholera
most isolates of Shigella species were highly resistant tosensitivity pattern has been constantly seen in the past
decades (Smollan and Block, 1990; Voogd et al., 1992).

We can not account for the reason why Indonesianisolates have a tendency to be resistant to the new
antimicrobials such as cefdinir and ofloxacin. Oflox‑
acin, (a new quinolone) and cefdinir (a new oral ce‑phem) are excellent to inhibit the growth of Shigella.
but ofloxacin is not preferable to use in the pediatriccases and cefdinir is expensive. Erythromycin (ma‑TC and ABPC. However, the sensitivity pattern is

crolide) is basically not effective to inhibit the growth ofdifferent from the place to place of isolation (Table 2) .

enterobacteriaceae. Actually, high MICs against Shigel ‑The isolates of Japan were relatively sensitive to thesela are shown in the present study. However, there weremany facts in the past that erythromycin was effective
for the treatment of shigellosis regardless the drug
sensitivities (Saito et al., 1964; Ukai et al., 1965).
Recently, moreover, it is widely recognized that eryth‑romycin is effective to panbronchiolitis infected with
Pseudomonas aerginosa (Unertl et al., 1986). Therefore,
it may be beneficial to use erythromycin for diarrheal
diseases due to bacterial enteritis. Erythromycin is thefirst choice of drug for Campylobacter diarrhea and is
known to be effective to Vibrio diarrhea (Burans et al.,traditional antibiotics. The Indonesian isolates have atendency to become resistarit even against OFLX, andactually there was one strain with the MIC of OFLX at
100 pg/ml. In these sensitivity pattern, a new oral

cephem CFDN has a considerably good anti‑Shigellaactivity. Visual impression of these different sensitiv‑
ities is shown in Figure 1.

MIC50 and MIC90 account for the variety of drug
sensitivity of Shigella and the resembling sensitivity of
V. cholerae (Table 3) .

1989; Kobari et al., 1967). If eryhromycin is effective to

DISCUSSION

shigellosis, there is a good possibility that it is also
effective to E.coli diarrhea. Clinical trials and the study

Results of the present studies revealed that recently

to clarify the mechanism of erythromycin activities are

isolated cholera vibrios have almost the same drug

required.
'This study was supported by a grant‑in aid forsensitivity pattern to V. cholerae O1 isolated in the past

3 decades (Iwanaga et al., 1982; Iwanaga et al., 1979).

Although V. cholerae 0139, a new cholera vibrio, is
known to be resistant to co‑trimoxazole (Yam et al.,1994) , there must be no difficulties in the antimicrobial

therapy for cholera at present. No resistant V. cholerae

strain against the traditional antibiotics was found in
this study. The sensitivity of V. cholerae 0139 against

PLB was different from the previous report by Sarkar
et al. in which they described that the MICs were 15 to
50 pglml (Sarkar et al., 1993).

On the contrary, Shigella species showed a varietyof drug sensitivities as being expected. It is interestingthat the isolates of Japan are relatively more sensitive

to tetracycline and ampicillin than those of the othercountries. Japanese isolates were obtained from the‑epidemics in two separated areas of Okinawa. The
cases were indigenous and not imported ones. The

scientific research from the Ministry of Education,Sci‑
ence,and Culture of Japan (No. 07922097).

REFERENCES
1 ) Burans, J.P., Podgore, J., Mansour. M.M., Farah, A.H.,
Abbas, S., Abu‑Elyazeed, R. and Woody, J. N. (1989) :Comparative trial of erythromycin and sulphatrimetho‑
prim in the treatment of tetracycline‑resistant Vibrio
cholerae O1, Trans R. Soc. Trop. Med. Hyg., 83, 836‑838
2 ) Carlson, J. R., Thornton, S.A., DuPont, H.L.,West, A.H.
and Mathewson, J.J. (1983) : Comparative in vitro activ‑
ities of ten antimicrobial agents against bacterial enter‑

opathogens, Antimicrob. Agents. Chemother., 24,509‑13
3 ) Glass, R.1., Hug, I., Alim, A.R.M.A. and Yunus, M.
(1980): Emergence of Multiply Antibiotic‑ResistantVibrio cholerae in Bangladesh, J. Infecti. Dis., 142,939‑
942

161

Table1

MICs

of5antimicrobial

agents

12．5

25
50

100
100＜

0．1

0．2
．0．4

0．8

1．6
3．13

6．25
12．5

25
50

100
100＜

ABPC

OFLX

EM

00
01
01
00720200
00000107000000148000

6．25

0．05

TC

00000000000
8000000003
0000000001

3．13

0．025≧

PLB

00000008000
00
00
00001111000
00
00
00
00328000

1．6

India

01
02
09
01000000
00080000000102
01
0000000
00000000000
1000
70000000000
20
10
1000000019

0．8

4

EM

01
00
00
000
00
00
10
10165900083300
00000001390
000

0．4

OFLX

00000000000
0000000006
02000000001

0．2

ABPC

1
90
08
06
00 00000023900
00
000
00000001327
00
00
00

0．1

TC

00
150
630
00．
0000000
000040000000
0
0

0．05

PLB

7 010002070
00
0400000020
1030
90000000000000
000

0．025≧

O139

Vπ．ohoJ6名π80139

V＝．ohoJ召πz801

Argentina

againstγ．ohoJ徽召01and

total

40

40

40

40

40

total

8

8

8

8

8

Indonesia

PLB

TC

ABPC

OFLX

EM

Bangladesh

PLB

TC

ABPC

OFLX
1

EM

13

13

OFLX
3

EM

31

31

0．025≧
0．05

0．1

0．2
0．4

0．8
1．6
3．13
6．25
12．5

25
50

100
100＜

78

78

Laos

PLB

TC

0．025≧
0．05

0．1

0．2
0．4

0．8
1．6
3．13
6．25
12．5

25
50

100
100＜
total

41

000437000000

total

41

7

0．025≧
0．05

0．1

0．2
0．4

0．8
1．6
3．13
6．25
12．5

25
50

100
100＜

78

78

78

total

13

13

13

ABPC

OFLX

EM

Thailand

PLB

TC

ABPC

31

31

41

4

41

41

0．025≧
0．05

0．1

0．2

0．4
0．8

1．6
3．13
6．25
12．5

25
50

100
100＜
tota1

31

162

Table2MICs

of5antimaicrobial

agentsagainstSh憩召1伽spp．

Sh⑫召1如SPP．

50

68

Dominica
0．025≧
0．05

0．1

0．2

0．4
0．8
1．6
3．13
6．25
12．5

25
50

100
100＜

1ndonesia
0．05

0．1

0．2

0．4
0．8
1．6

3．13
6．25
12．5

25
50

100
100＜

68

68

68

ABPC

0FLX

EM

21

21

21

21

21

CFDN

TC

ABPC

0FLX

EM

46

46

−

46

46

46

0．2
0．4

0．8
1．6

3．13
6．25
12．5

25
50

100
100＜

Kenya
0．025≧

0．05
0．1
0．2
0．4

0．8
1．6
3．13

6．25
12．5

25
50

100
100＜

Japan
0．025≧
0．05

0．1
0．2

0．4
0．8
1．6
3．13

6．25
12．5

25
50

100
100〈

OFLX

EM

13

13

13

13

13

CFDN

TC

ABPC

0FLX

EM

10

10

10

10

10

CFDN

TC

ABPC

0FLX

EM

33

33

33

33

21⊥

0．025≧

CFDN

9ムー⊥

100
100＜

0．1

ABPC

00000000000
50
40
30
1000000
80
101000
2 0001

25

0．05

TC

001
0000000
01030000002
08
00
00
00
00000002

12．5

0．025≧

CFDN

0000010330000
20411030000
220
3016600

3．13
6．25

Laos

000001000000
60
50
120000000
1060
18250000
003640000006
04
0000000021
08
03
0100000

1．6

EM

03
010
20
30
11
00102719
000000004330
31
30
200186
00

0．8

OFLX

00
10
70
40
0000000
01050
21650000000
90
1074000000

0．4

1⊥

0．2

ABPC

00000128
7300
10
10
40
3001320
10000
5317
り乙
⊥ 5600

0．1

TC

8
C
00000261402
4591100000
00
40
52
3321
0004
62T
可⊥

0．05

CFDN

00
008
01
08
010
00372460001
09
04
0000002084210100

Bolivia
0．025≧

33

163

% 90

IOO

I Japanl Indonesia

% 90

80

80

70

70

60

60

50

50

40

40

30

30

20

20

lO

lO

O

O

l .6 6.25

0.025 ; O. I 0.4

U.05 0.2 0.8

3.13 12.5

25 50 100 100<

TC

b.
ICO

0.025 ;

O. I 0.4

U.05 0.2 0.8

D Indonesia

80

70

60
50

50

40

40

30

30

20

20

lO

lO

B Dominica

O

0.025

: O l
25 50 100100<
04 0.8 l.6 6.25
U.05 ' 0.2 '3.13 12.5

p g/mlABPCc.

I Japan

D Bolivia% 90

Dominica

80
70

60
50

40
30
20
10

O

0.025 ;

O. I 0.4

U.05 0,2 0.8

apan

80

60

IOO

p g/ lD Bolivia

% 90

70

0.025 0.05
; O l' 0.2 04 08 l .6 6 25
25 50 100100<
3.13 ' 12.5

25 50 100 100<
l.6 6.25
3.13 12.5

EM

e.
IOO

l Japan90O

I Bolivia
D Indonesia

p g/ml

f ,

OFLX

d.

CFDN

a.
IOO

25 50 100100<
l.6 6.25
3.13 12.5
p glmlFigure 1 Visual expressron of the sensitivities for Shigellap g/ml164

Table 3 Variability and Constancy of MIC
Shigella spp.

Bolivra Dominica

CFDN MIC5'
MIC90Indonesia

Laos

Keny a

Japan

0.1
0.2
100
100

0.2
0.4
1.6
1.6

0.1

0.2

0.2

0.2

0.2

0.4
100
100 <

0.4
50

MIC90

100 <

0.4
50
100 <

ABPC MIC=.

100

100 <

lOO

6 . 256 . 253 . 13

MIC90

100 <

100 <

100 <

100 <

100 <

6 . 25OFLX MIC=,

O . 05

O . 050.1

O . 05

O . 05

O . 05MIC90

O . 050.1

0.1

O . 0525

12 . 5

50

50

100

25
50

0.1
100

100

0.4
25
100

TC MIC=0lOO

EM MIC=.
MIC90

1 OO

100

V. cholerae O1 & 0139

Argentina Indonesia

PLB MIC=,

Laos

India

Bangladesh

Thailand

lOO

100
100

lOO
100

0.2
0.2

100
100
0.2

100<

100

MIC*.

100 <

100

TC MIC50

0.4
0.4

0.4
0.4

100
0.4
0.4

ABPC MIC5"

6 . 256 . 256 . 253 . 133 . 133 . 13MIC*,

6 . 2512.5

6 . 253 . 133 . 133 . 13

OFLX MIC50

O . 025 ;O . 025

O. 025

O . 025

O . 025o. 025 ;MIC..

O . 025 ;O . 025o. 025

O . 025

O . 025o. 025MIC..

EM MIC=0
MIC,.

;

0.2

0.2
0.2

6 . 256 . 256 . 253 . 133 . 133 . 136 . 256 . 256 . 253 . 133 . 133 . 134 ) Iwanaga, M., Mori, K. and Kaviti, J. N. (1982): Vibrio
cholerae O1 Isolated in Kenya, J. Clin. Microbiol., 16, 742‑7435 ) Iwanaga, M., Shigeno, H., Hayashi, T., Utsunomiya, A.
and Naito, T. (1979) : Drug Sensitivity of E1 Tor Vibrio,

Trop. Med., 21, 11‑206 ) Kobari, K., Uylangco, C., Vasco, J., Takahi.ra, Y. andShimizu, N.(1967): Observations on Cholera TreatedOrally and Intravenously with Antibiotics, Bull. Wld.
Hlth. Org., 37, 751‑762

7 ) Ramamurthy. T., Pal. A., Pal, S.C. and Nair, G.B.
(1992): Taxonomical Implications of the Emergence ofHigh Frequency of Occurrence of 2,4‑Diamin0‑6,7‑
Diisopropylpteridine‑Resistant Strains of Vibrio choler ‑ae from Clinical Cases of Cholera in Calcutta. India, J.
Clin. Microbiol., 30, 742‑743
8 ) Saito, M., Yamaguchi, T. and Sato, H. (1964): ClinicalUse of Erythromycin Estolate against Bacillary Dysen‑
tery, J. Jpn. A. Inf. Dis., 38, 327‑332
9 ) Sarkar, B. L., De, S.P., Sircar, B.K.. Garg, S., Nair, G.B.

and Deb, B.C. (1993): Polymyxin B sensitive strains ofVibrio cholerae non‑OI from recent epidemic in India,
Lancet, 341, 1090.

10) Smollan, G. and Block, C. (1990): Development of
antimicrobial drug resistance among Shigellas isolated;

at an Israeli hospital from 1977 through 1990, Public
Health Rev., 18, 319‑327
11) Towner, K. J.. Pearson, N.J., Mhalu, F.S. and O'Grady,F. (1980): Resistance to antimicrobial agents of Vibrio
cholerae El Tor strains isolated during the fourth chol‑era epidemic in the United Republic of Tanzania, Bull.
Wld. Hlth. Org., 58, 747‑751

12) Ukai, S., Hori, K., Yanagishita, T., Takayama, Y.,
Miyaji, H., Ono,Y. and Okajima, S. (1965): Treatmentof Bacillary Dysentery with Erythromycin Estolate(Ilosone) , J. Jpn. A. Inf. Dis., 39, 330‑335

13) Unertl, K., Lenhart, F.P. and Ruckdeschel, G. (1986):
Treatment of bronchopulmonary infections in patientsduring artificial respiration with imipenem/cilastatin,
Immun. Infekt., 14, 229‑231
14) Voogd, C. E.. Schot, C. S., van Leeuwen, W. J. and vanKlingeren, B. (1992): Monitoring of antibiotic resis‑
tance in shigellae isolated in The Netherlands 1984‑1989,
Eur. J. Clin. Microbiol. Infect. Dis., 11, 164‑167

15) Yam, W. C., Yuen, K. Y., Wong, S.S. and Que, T.L.
(1994): Vibrio cholerae 0139 susceptible to vibriostatic

agent 0/129 and co‑trimoxazole, Lancet, 344, 404‑405
16) Yamamoto, T., Nair, G.B., Albert, M. J., Parodi, C. C.
and Takeda, Y. (1995) : Survey of In Vitro Susceptibil‑
ities of Vibrio cholerae O1 and 0139 to Antimicrobial
Agents, Antimicrob. Agents. Chemother., 39, 241‑244

165

Jpn. J Trop Med Hyg., Vol. 23, No. 3 (1995) pp. 165‑167

The frequency of healthy carriers withenteropathogenic Bacteria
in Surabaya, Indonesia
A study in an elementary school
NOBORU NAKASONE1 MASAAKI IWANAGA1'2, EDDY BAGUS WASIT03,4, LlNDAWATI ALIMSARD JON03,
AND THOMAS VALENTlNUS WIDIYATN03
Received July 20, 1995/Accepted August 11, 1995

Sumlnary: A total of 953 stool samples from the healthy children of a elementary school located in thesuburb of Surabaya City, Indonesia, were examined for Shigella. Salmonella. Vibrio cholerae. V. para‑
haemolyticus, and four kinds of diarrheagenic Escherichia coli excluding enteroadnerent aggregative E. coli.
The carrier rate was 6.8% (65 children out of 953) . Enteropathiogenic E. coli was isolated from 42 children,
but the other diarrheagenic E. coli were not detected. Shigella spp. and V. cholerae non‑OI were isolated
frorn 12 and 11 children, respectively.

INTRODUCTION
Although the mortality rate of diarrheal diseases
has markedly decreased in the past 10 years, it is still a

big health problem in the tropical countries. The use ofclean water and the sanitary behavior of the individual
are essential in the control of diarrheal diseases in thecommunities. The sanitary situation of a community
can be evaluated by examining the healthy carrier rate

MATERIALS AND METHODS
Stools samples: The stools were collected from a totalof 953 children in elementary school in the suburbs ofSurabaya City, Indonesia. All stool samples examined
were normally formed, and the children were all healthy
at least when the stools were collected. The children
were between 5 and 15 years old, and the male to female
ratio was 505 to 448. Sampling was carried out in 9 daysin that area. Indeed, secretory diarrhea can now betreated properly at the community level using oral
rehydration therapy, but the invasive diarrhea due tobetween February 7 and 15, 1995.

Shigella species and enteroinvasive E. coli are out ofhand because of multi‑antibiotic resistant or anisms.
The strategy to eliminate a certain disease from an area
is introduced by the precise epidemiological data of thedisease. We have been studying the causative agents ofdiarrheal diseases in Surabaya, Indonesia for the past
several years (Iwanaga et al., 1993; Nakasone et al.,1994). Herein, we describe the healthy carrier rate ofenteropathogenic bacteria in the pupils of an elementary
school located in the suburban area of Surabaya City,

examined for V. cholerae O1, non‑OI and V. para ‑Indonesia.

Bacteriological examination: All samples were
haemolyticus. Aeromonas. Salmonella and Shigella. We
examined 362 samples for diarrheagenic Escherichia coli
(enteropathogenic‑, enterotoxigenic‑, enteroinvasive‑,and enterohemorrhagic‑E. coli ; EPEC, ETEC, EIEC,
and EHEC, respectively) . About 0.1 g of stool was
mixed with I ml of alkaline peptone water in an Eppen‑

dorf tube. After mixing it well by using a vortex
machine, Iarge fecal materials in the tube were removed
by flashing centrifugation at 15000 rpm for 5 seconds.
Fifty micro‑ Iiters of the supernatant was placed on a

MacConkey agar plate for E. coli, and SS agar for
Shigella and Salmonella. The inoculum was spread out
1)
2)
3)
4)

Department of Bacteriology. Faculty of Medicine, University of the Ryukyus. Okinawa 903‑01, Japan.
Research Institute of Comprehensive Medicine, Faculty of Medicine, University of the Ryukyus, Okinawa 903‑01. Japan.
Department of Microbiology, Faculty of Medicine, Airlangga University, Surabaya, Indonesia.
Tropical Disease Research Center, Airlangga University, Surabaya, Indonesia.

166

to a half space of the plate using a glass bar spreader
and streaked to the other half space using an inoculum
wire loop. The samples in Eppendorf tubes were left atroom temperature (Ca. 25'O overnight, and then 50 pleach of them was inoculated on TCBS agar plate in thesame manner as described above. As a rule, 4 colonies

Tabel 2 Serovar distributionof EPEC, 42 strains

EPEC
Class I

each of lactose fermentative and non‑fermentative
organisms were subcultured on nutrient agar plate (8The organisms suspected as diarrheagenic E. coli wereidentified by examining their biological properties.
Class II

V. cholerae were serogrouped by a slide agglutination
test using commercial antisera (Denkaseiken) .

Examinations for virulence factors: EPEC was
identified by glass slide agglutination test using com‑
mercially purchased anti‑EPEC sera. Heat labile E. coli

026
055
086

2
3

O111
O119
0126
0127
0128
0142

strains per plate) to examine for diarrheagenic E. coli.

Serotyping: All E. coli strains, Salmonella. Shigella, andNo. of strain

6
2
3
11

018
044
O114

1

5
4
3

Tabel 3 Distribution of Shigella spp.
Shigella

No.of strain

S. dysenteriae (not type D

enterotoxin (LT) was examined by the Biken‑method

S. flexinneri(Honda et al., 198D, and heat stable toxin (ST) by the

S. boydii

7

immunoenzyme assay (IEA) using a detection kit,

S. sonneio3

COLIST (Denkaseiken) . EIEC and EHEC werescreened by sero‑agglutination, and then examined bypolymerase chain reaction (PCR) according to themethods of Lampel et al. (1990) and Kobayashi et al.
(1990) for the primer sets and conditions of reaction,
res pectively.

but the H‑antigen of the two isolates was not H7 andone isolate was non‑motile. The genes encoding VT‑I
or VT‑II were not detected from the strains with 0157

and 026 by PCR. There were many serotypes in the
EPEC isolates, and among them, antigen 0128 wasdominant (Table 2). Shigella was isolated from 12 outof 953 children (1.3%) including 7 isolates of S. boydii, 3

RESULTSof S. flexneri, 2 of S. dysenteriae (not type 1), and none

Diarrheagenic E. coli was isolated from 42 out of
362 children (11.6%) , and all of them were EPEC (Table
D . There were 31 isolates with the serotypes of EIEC orof S. sonnei (Table 3). The serotypes of 11 isolates ofV. cholerae did not belong to O1 or 0139. Salmonella. V.
parahaemolyticus, and Aeromonas were not detected.

with EIEC biochemical behavior. However, these iso‑lates were all negative for invasive plasmid as examinedby PCR. There were three isolates with serotype 0157,
Table I Isolation frequency of enteropathogens

Enteropathogens No of posrtrve (%) No. examined

EPEC

42

11.6

ETEC

O

O

EHIC

o

O

EIEC

o

O

Shigella spp .

12

1.3

Salmonel laOO

V. cholerae O1OO

V. cholerae non‑O1

11

1.2

V. parahaemolyticus

OO

Aeromonas spp.

O

O

362

DISCUSSION
In this study, the carrier rate of EPEC was high(11.6%), and no ETEC were isolated. Recently, Albert
et al. (1995) reported that the carrier rate of EAF
positive EPEC (Class I EPEO in Bangladesh was 5.3%(331602) and (Class 11 EPEO was isolated in 7.3 %.
Although the definition of EPEC is still in controversy,

E. coli bearing the EAF plasmid is considered to be
definite EPEC, and called "Class I EPEC" (Levine,
9531987) . Reviewing the data in the present study in accor‑
dance with that classification, Class I specific serotypes

were found in 30 out of 362 (8.3%) isolates examined
and Class 11 specific serotypes in 12 (3.3%). The isola‑tion frequency of ETEC from human beings with orwithout diarrhea is usually less frequent than that of

167

EPEC (Albert et al., 1995; Chatkaeomorakot et al.,
1987; Echeverria et al., 1987; Georges et al., 1984; Gomes
et al., 1989, 1991 ; Toledo et al., 1983) , and in the present

study, no ETEC were isolated. Nevertheless, the detec‑tion of ETEC from Japanese travellers returning fromthe developing countries is far more frequent than thatof EPEC (Kudoh et al., 1993; Yoshida et al., 1992). To
explain this discrepancy, continuous monitoring for thedetection of ETEC and EPEC is required.
The Shigella positive rate of 1.3 % was as expectedfrom our previous experiences. How many of thesecarriers develop illness is a problem to be clarified infuture. Salmonella tends to stay in the intestine for a

Republic. J. Clin. Microbiol., 19, 571‑575
5 ) Gomes, T. A. T., Blake, P. A. and Trabulsi. L. R. (1989) .

Prevalence of Escherichia coli strains with localized,

diffuse, and aggregative adherence to HeLa cells in
infants with diarrhea and matched controls. J. Clin.
Microbiol., 27, 266‑269
6 ) Gomes, T. A. T., Rassi, V., MacDonald, K. L., Ramos, S.
R. T. S., Trabulsi, L. R., Vieira, M. A. M., Guth, B. E. C.,

Candeias, J. A. N., Ivey, C., Toledo, M. R. F. and Blake,

P. A. (1991). Enteropathogens associated with acutediarrheal disease in urban infants in S o Paulo, Brazil.
J. Infect. Dis., 164, 331‑337

7 ) Honda, T., Taga, S., Takeda, Y. and Miwatani, T.
(1981) . Modified Eleck test for detection of heat‑1abile
enterotoxin of enterotoxigenic Escherichia coli. J. Clin.

long time, but there were no carriers in the examined
population. The distribution density of Salmonella must
be very low in this area. On the contrary, although V.

8 ) Iwanaga, M., Nakasone, N., Nakamura, S., Wasito, E.
B., Soeparto, P., Sudarmo, S. M., Soewandojo, E. andcholerae tends to stay in the intestine for a short period,
it was detected from 11 children out of 953 (1.2%) . Thisdiseases in Surabaya, Indonesia. Jpn. J. Trop. Med.

suggests that the people in this area frequently ingest

the organisms, probably because of water contamina‑tion. However, the carriers of enterobacteiaceae such
as E. coli. Shigella and Salmonella, suggest the presenceof fecal‑oral infection. The development of a strategy
to prevent diarrheal diseases in this area is awaited.

Microbiol., 13, 1‑5R,anuh, I. G. N. G. (1993) . Etiologic agents of diarrheal

Hyg., 21, 143‑147
9 ) Kobayashi, K., Seto, K. and Makino, M. (1990). Detec‑tion of two Shiga‑like toxins from Escherichia coli 0157:

H7 isolates by the polymerase chain reaction method.
Jpn. J. Bacteriol., 45, 649‑652

10) Kudoh, Y., Matsushita, S., Yamada, S. and Ohta, K.
(1993) . Current status of Shigellosis in Tokyo andcharacterization of Shigella isolates. The 29th JointACKNOWLEDGMENTS
We thank Kazuhiro Kobayashi, Osaka Prefectural
Institute of Public Health, for kindly providing EHEC

strains, and Musyadi and Moh. Choesen Masjkoer for
their kind assistance.

REFERENCE
1 ) Albert, M. ,J., Faruque, S. M., Faruque, A. S. G., Neogi,

P. K. B., Ansaruzzaman, M., Bhuiyan, N. A., Alam, K.
and Akbar, M. S. (1995) . Contrblled study of Escherichia
coli diarrheal infections in Bangladesh children. J. Clin.

Microbiol., 33, 973‑977

2 ) Chatkaeomorakot, A., Echeverria, P., Taylor, D. N.,
Bettelheim, K. A., Blacklow, N. R., Sethabutr, O., Ser‑
iwatana, J. and Kaper. J. (1987) . HeLa cell‑adherent
Escherichia coli in children with diarrhea in Thailand. J.

Infect. Dis., 156, 669‑672 .
3 ) Echeverria, P., Taylor, D. N., Bettelheim, K. A.. Chat‑kaeomorakot, A., Changchawalit, S.. Thongcharoen, A.
and Leksomboon, U. (1987) . HeLa cell‑adherent enter‑
opathogenic Escherichia coli in children under I year of
age in Thailand. J. Clin. Microbiol., 25, 1472‑1475

4 ) Georges, M. C., Wachsmuth, I. K., Meunier, D. M. V.,
Nebout, N., Didier, F., Siopathis, M. R. and Georges, A.
J. (1984) . Parasitic, bacterial, and viral enteric path‑ogens associated with diarrhea in the Central African

Conference, U.S.‑Japan cooperative medical science
program on cholera and related diarrheal diseases panel.

Asilomar: U.S.A. 139‑143
11) Lampel. K. A., Jagow, J. A., Trucksess, M. and Hill, W.
E. (1990). Polymerase chain reaction for detection ofinvasive Shigella flexneri in food. Appl. Environ. Mi‑
crobiol., 56, 1536‑1540
12) Levine, M. M. (1987) . Escherichia coli that cause diar‑rhea: Enterotoxigenic, enteropathogenic, enteroinvasive,enterohemorrhagic, and enteroadherent. J. Infect. Dis.,

155, 377‑389
13) Nakasone, N., Iwanaga, M., Wasito, E. B., Soeparto, P.
and Ranuh, I. G. N. G. (1994) . Stool analysis of pediatricdiarrhea in. Surabaya, Indonesia. Jpn. J. Trop. Med.
Hyg., 22, 125‑127
14) Toledo, M. R. F., Alvariza, M. D. C. B., Murahovschi, J.,

Ramos, S. R. T. S. and Trabulsi, L. R. (1983). Enter‑

opathogenic Escherichia coli serotypes and endemic
diarrhea in infants. Infect. Immun., 39, 586‑589
15) Yoshida, A., Noda, K., Ornura, K., Miyagi, K., Mori, H.,

Suzuki, N., Takai, S., Matsumoto, Y., Hayashi, K.,
Miyata, Y., Taguchi, M., Tsukamoto, T., Ishibashi, M.
and Honda, T. (1992). Bacteriological study of travel‑
ler's diarrhoea. 4) Isolation of enteropathogenic bacteria

from patients with traveller's diarrhoea at Osaka Air‑
port Quarantine Station during 1984‑1991. J. Jpn. Assoc.
Infect. Dis., 66, 1422‑1435

l 69

Jpn. J. Trop. M*d' H**" vot' 23' N*' 3 (*995) " 169 *76

INTESTlNAL PARASITIC INFECTIONSIN SOME RURAL AND URBAN AREAS OF
THE DOMlNICAN REPUBLICAKIRA MrvATAl,3), HIDEO HASEGAWA2,3), MERCEDES CASTRO BELL03)

AND RAMON BARON3)
Received June 23, 1995/Accepted August 14, 1995
Abstract: A parasitological examination was conducted on fecal samples collected from 1,547 inhabitants
residing in 10 rural and two urban localities including a slum in the Dominican Republic. Seven helminthand seven protozoan species were observed. In the helminthic infections, Trichuris trichiura was commonestwith overall prevalence of 48.4%, being followed by Ascaris lumbricoides (prevalence 25.5%) and hook‑worms (12.9%) , while the prevalence of other helminthic infections was quite low, Iess than 3% for every
species. All of the filariform larvae of hookworms were identified as Necator americanus. The prevalenceof major geohelminth infections markedly differed by locality presumably due to the climatic andsocioeconomical differences. The prevalence of A. Iumbricoides infection showed a peak in the groups of 5‑
9 or 10‑14 years of age in the highly endemic localities, while that of T. trichiura and hookworm formed aplateau through the age groups of 5‑9, 10‑14 and 15‑24 years. Entamoeba coli was the most prevalent
protozoan being detected in 21.1% of the samples, followed by Giardia intestinalis (5.4%) ･ The prevalenceof protozoan infections was relatively stable among localities, suggesting that contaminated drinking wateror foods were the sources of infection.
Key words: Intestinal parasite infection, Dominican Republic, urban slum, rural area, epidemiology.

1987, 1990; Vincent et al., 1987. Hillyer et al., 1986) . On

INTRODUCTION
The Dominican Republic is located in the Caribbean

region occupying east twb‑thirds (ca. 48,442km2) ofHispaniola Island. The total population is approximate‑ly 6 millions of which about 2.4 millions reside in thecapital, Santo Domingo. The climate is of tropicaloceanic type with month,ly mean minumum temperature
ranging from 18 to 25'C and mean maximum tempera‑

the other hand, there have been only sporadic researches
on intestinal parasitic infections in limited localities(Mackie et al., 1951; Collins and Edwards, 1981; Vargas
et al., 1987), and any nationwide record has not been
available. During the medical cooperation project on
gastroenterology between the Dominican Republic andJapan aided by the Japan International Cooperation

Agency (JICA) , we had an opportunity to make ature 28 to 34'C in the areas along the coast. Rainy season

parasitological examination on feces from the inhabit‑

lasts from May to September in most regions except
northwestern and southwestern regions where rainy

ants in some rural and urban areas. The results areseason is absent. Annual precipitation is over 2,000mm
in northeastern region and 1.000 to 1,400mm in south‑
eastern coastal and west‑central regions, and less than
1,000mm in northwestern and southw. estern regions.
This country has been known as an endemic area ofsion.

schistosomiasis and Bancroftian filariasis on which
many reports have been made (cf. Vargas et al., 1981,

presented in this paper with an epidemiological discus‑

MATERIALS AND METHODS
Twelve localities, two urban and 10 rural, werechosen for survey (Fig. D. Fecal samples were col‑lected from inhabitants who voluntarily agreed to havel) Department of Biology, Oita Medical University, Hazama, Oita 879‑55, Japan
Department of Parasitology and Research Center of Comprehensive Medicine, Faculty of Medicine, University of the Ryukyus,

2)

Nishihara, Okinawa 903‑01, Japan

3)

JICA Proyecto de Investigacion y Clinica en Enfermedades Gastroenterologicas, Centro de Gastroenterologia, Hospital <'Dr. Luis

E. Aybar", Santo Domingo, Dominican Republic

1 70

the parasitological examination. A questionnaire on
socioeconomical and sanitary conditions was also madeat the delivery of container for fecal collection. Exami‑

Las Cuchillas, well water is used for drinking, and rainwater is stored in tank for washing and bathing use. In
these three areas, pit latrines are predominantly used,nation of feces was made with both Kato‑Katz smear
and formalin‑ether concentration techniques. Harada‑

but some inhabitants prefer to defecate in nearby

Mori culture was also applied for samples from El Valleand La Ci6naga. Agar‑plate culture of feces for Stron ‑gyloides stercoralis detection (Arakaki et al., 1988) was

the soil is usually wet.

bushes. Annual precipitation is more than 2,000mm, anddone only for 126 samples from La Cienaga. All of the

Dajab6n is located at the northwestern border with
Haiti. The altitude is less than 50m from sea level, andits climate is hot and dry. Annual precipitation is lessinhabitants who were proved to have helminthic andGiardia intestinalis infections were treated free ofthan 800mm and rainy season is absent. People engage
in rice paddy cultivation and cattle‑breeding, and arecharge.

relatively wealthy.

Statistical analysis of prevalence data between
groups was performed by Chi‑square test with Y ates'

Constanza and Jarabacoa are farming areas locatedin the west‑central of the country and with altitude ofcorrection for continuity (significance level : p < 0.05) .

1,200m and 500m from sea level, respectively. Monthly

mean minimum and maximum temperatures in Constan‑

OUTLlNE OF THE SURVEYED LOCALITIESLa Ci6naga is a typical urban slum of Santo Domin‑go, and is located along the west side of the River
Ozama. This area is on the flood plain of the river, andthe soil is often moist. Most of the inhabitants are poor

immigrants from rural areas and residing in temporary

huts made of zinc plates, corrugated cardboards,
polyvynyl sheets and wood pieces. In rainy season,
floods sometimes sweep away such huts along withinhabitants to the sea. Tap water supply is available
only in limited houses, and majority of the inhabitants
obtain water from common taps. Most lavatories are ofquite simple pit latrine type. Many small streams withfilthy water run through the area. The water of theRiver Ozama is contaminated with sewage from Santo
Domingo city, but some poor people of La Ci6naga
utilize it for washing and bathing.

Villa Duarte is located along the east side of theRiver Ozama, and is on a cliff with 10m height from theriver surface. This ar a is provided with drain systemza are 9‑13'C and 23‑26'C, respectively. Annual precipi‑

tation in Constanza is about 1.000mm. Former Japanesesettlements, now inhabited by a few Japanese immi‑
grants and many Dominicans, were chosen for survey.
Water from mountain streams is supplied through pipes.
The houses of Japanese immigrants have flush toilets or
latrines of permanent structure, and the excreta fromthese lavatories penetrate into bottom soil. Most of the
Dominican inhabitants use simple pit latrines.

Juancho, Oviedo, Pedernales and La Cueva arelocated along coast of southwestern part of the country.

Annual precipitation is less than 1.000mm without rainyseason, making the climate hot and dry, and the villages

are often surrounded by cactus fields. Most people
examined were fishermen, cattle‑breeders and theirfamily members, and were very poor generally. Tap
water supply is not available, and water wagons supply
river water once a week. The supplied water is storedin open drum cans in front of the houses. Simple pit
latrines are used, but people often defecate within near‑by bushes. The data of Juancho and Oviedo were,

and the soil is usually dried. The inhabitants of this area

combined together because of small sample size andare composed of middle or somewhat lower classes.
Tap water supply is available and most houses have

similar natural and socioeconomical conditions between
the localities. With the same reason, the data of Peder‑
nales and La Cueva were joined together.

flush toilets or pit latrines. Most of the middle‑classinhabitants buy bottled sterilized water for drinking.

Saman , Las Cuchillas and E1 Valle are located in
the northeastern region of the country (Fig. 1). In
Saman , a small coastal village was investigated. This
village is encircled by coconuts plantations, and people
engage in agriculture and fishery. The inhabitants of
Las Cuchillas and El Valle are mostly farmers cultivat‑

ing coconuts, oil palm, banana and coffee or cattle
breeders. In Saman and El Valle, water supply isavailable, but taps are settled outside of the houses. In

RESULTSA total of 1,547 inhabitants (752 males and 795
females) were examined, and seven helminth and sevenprotozoan species were detected from them. Table 1
shows the parasite prevalence by locality and sex. The
most prevalent helminth was Trichuris trichiura in all
localitles except Dajab6n, where prevalence of soil‑tran‑

smitted nematode infections was quite low and

171

N

4 r( 4,Vrl clr. '¥‑.r Dajabo'n̲‑.[ 7'
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r'¥ . ./ ¥'¥.

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b ¥¥
/ A ¥̲ ‑ L>' ',Jarabacca
A ¥1rJ'¥t JL ./ '/j At¥.

)//‑FL J' A f /' :'. 1! ' '¥' ¥"¥:1 . ) ' ¥,1'/' l''¥ : ( '¥. . ).r'¥'1*'/'¥ samana.̲ :'¥,f'‑'.),¥ .A Y' ･ I/ . / ' '(' A /)JL A¥.‑. ( e Las cuchillas
El V 1,le

A
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4p 188. ¥¥. . ' ¥ (:.)

pedernaies JL

La culeva ¥. ' Juancho¥.

Oviedo O 50km

e Localities surveyed
O prefectural capitals
National roads

C 41V
SC

d

‑'‑ prefectural border
JL Mountain peaks (height I .OOOm or more)
A Mountain peaks (height less than I ,OOOm)
Lakes

Figure 1 A

ap of the Dominican Republic showing localities where parasitological examination was made.

Hymenolepis nana was the most prevalent helminth

The prevalence of hookworm infection was much

(6.8%) (Table l). The prevalence of Trichuris infection
was especially high in El Valle (78.7%) and La Ci6naga

higher in the northeastern localities than in other local‑(67.1%), and it exceeded 50% in Saman , Juancho/

than 50% of the inhabitants were positive. In La
Ci6naga, hookworm prevalene was low (6.3%), and it

Oviedo and Pedernales/La Cueva (Table D . The preva‑
lence of Trichuris infedtion in Villa Duarte, Las Cuchil‑las, Constanza and Jarabacoa showed no significant

ities (Table D. It was highest in El Valle where more

was much lower (3% or less) in Villa Duarte, Dajab6n,Constanza, Jarabacoa, Juancho/Oviedo and Pedernales/

Ascaris lumbricoides was the next prevalent hel‑

La Cueva. All of the filariform larvae of hookworms
obtained by Harada‑Mori culture were identified asminth except in the northeastern localities, i.e.Saman ,Necator americanus. Strongyloides stercoralis infection

Las Cuchillas and El Valle, where the prevalence of

was less common, but was detected also in Jarabacoa

difference statistically from each other.

hookworm infection was much higher (Table 1).

and Juancho/Oviedo, where hookworm infection wasAmong the localities, the prevalence of Ascaris infection

not proved (Table 1). Hymenolepis nana was detectedin eight out of the 12 Iocalities surveyed, while
Hymenolepis diminuta was proved in only one sample

was highest in La Ci6naga, but not significantly differ‑ent from that in El Valle and Juancho/Oviedo. Villa
Duarte, Constanza, Jarabacoa and Pedernales/La Cueva
showed moderate prevalence of Ascaris infection, being
not different from each other significantly. Ascaris
prevalence was quite low in Saman and Las Cuchillas,
where Trichuris prevalence was more than eight times
as high as Ascaris prevalence. In Dajab6n, only one childharbored Ascaris.

(Table 1) .

Contrasting to helminthic infections, the prevalenceof protozo tn infections was relatively stable. The
overall protozoan prevalence was ranging from 10 to
30% among the localities except La Ci6naga and El
Valle where protozoan infections were rather common(Table l).
The most prevalent protozoan was

172

Entamoeba coli that was detected in every locality. The
prevalence of E. coli infection was highest in La Ci6naga

inhabitants in El Valle, La Ci6naga and Saman , respec‑tively, while such infection was less than 10% in otherand lowest in Villa Duarte (Table 1). However, its

localities. In Dajab n where the parasite prevalence
was lowest (32.5%) , double infection was demonstrated

prevalence in La Ci6naga was not significantly higher
than that in Saman , Las Cuchillas, Jarabacoa, Juan‑cho/Oviedo. Also, nd significant difference was obser‑
ved statistically in E. coli prevalence among Saman ,Las Cuchillas, El Valle, Dajab6n, Constanza, Jarabacoa,tion was not observed.

Juancho/Oviedo and Pedernales/La Cueva. The preva‑

females in total (p < 0.005), while Ascaris prevalence

lence of Giardia intestinalis infection was highest in La

was not different siguificantly between sexes. The

Ci6naga (15.7%) , being followed by Las Cuchillas and El

Valle (Table D.
Multiple infections were demonstrated in 44.8% of
the inhabitants examined in total (22.9% with 2 parasite
species, 11.8% with 3, 3.6% with 4, 1.0% with 5 and 0.3%
with 6) . The frequency of multiple infections showed aclear correlation with the prevalence of paraistic infec‑
tions in the localties. In E1 Valle and La Ci6naga where

overall prevalence was about 90% (Table 1), multiple
infection was observed in 69.8% and 64.4% of the inhab‑
itants, respectively. In the localities with overall para‑site prevalence ranging from 65 to 75%, multiple infec‑
tion was found in 30 to 45% of the inhabitants. In the
Iocalities with parasite prevalence of 45 to 50%, multiple

only in 1.7% of the inahbitants and triple or more infec‑

The prevalence of Trichuris, hookworm and H.
nana infections was significantly higher in males than inprotozoan prevalence showed no clear difference
between sexes except that E. coli infection was signifi‑

cantly higher in females (Table 1). This was due to themuch higher prevalence of E. coli infection in females(36.8%) than in males (28.6%) among adults (aged 15
or more) in La Ci6naga, while it was same between
sexes among young inhabitants (aged O to 14 years) .

The age‑related prevalence of three major soil‑transmitted helminthic infections by locality was shownin Figs. 2‑4. The data of the west‑central two localities

and the southwestern four localities were combined
together. The data of Villa Duarte and Las Cuchillas

were excluded becuase of small sample size. In La

Infection was found in 17 to 26%. Triple or more

Ci6naga and the southwestern localities, the prevalenceof Ascaris infection was already more than 30% in theinfections were found in 43.2, 31.8 and 15.0% among theyoungest age class (0‑4 years) (Fig. 2). In all localities

Table 1

Prevalence of intestinal parasitic infections in the Dominican Republic, 1993‑1995.
Urban Areas

Locality

No. examined

Rural Areas

Santo Domingo

Northeastern(CapitaD

Regi onNorthwestern

RegionLa Ci6naga Villa Samana Las Cu‑ El(slum) Duarte
chillas Valle
395

Helminths

70 180 85 169

Da jab6n

Sex

West‑central
RegionCons‑ Jaraba‑ Juancho/ Pedernales/ Males Females

tanza coa Oviedo La Cueva

237 147 78

87

Ascaris lumbricoides

46 . 3%25 . 77.2

4.7

37 . 90.4

22 . 417.9

37 . 9Trichuris trichiura

67 . 131 . 458 . 342 . 478 . 7

4.2

29 . 933 . 356 . 3

1.4

3.8

2.3

Hookworm

6.3

30 . o22 . 454 . 4

1.7

Strongyloides stercoralis

2.5

9.4

4.7

4.1

0.4

Enterobius vermicularis

0.5

0.6

0.6

0.4

0.7

Hymenolepis nana

0.8

0.6

6.8

1.4

Hymenolepis diminuta
Subtotal

47 1 68 9 54 1 86.4

99

752 1574
795

32 . 3 25 . 8
58 . 6 52 . 5

25 . 325 . 544 . 448 . 4

3.0 15.6

l0.3

12 . 91.0 3.3

2.5

0.8

1.3

3.4
1.1

75 . 2

Total

Southwestern
Region13 5 40 1 39 7 66.6

1.0 1.6

2.9
0.4

1.9

0.l

1.7
0.1

63 . 6 62 . o 53 . 2 57 . 5

Protozoans
Entamoeba histolytica

4.1

1.4

Entamoeba hartmanni

2.8

1.4

Entamoeba coli

28 . 4

7.1

Endolimax nana
Iodamoeba buetschlii
Giardia intestinalis

15.7

2.9

Chilomastin mesnili

1.3

1.4

3.0

3.3 1.2

0.7

4.7

23 . 9 18 . 9

20 3 13.6

13.9

3.5 13.0

0.7

9.1

3.0

20 . O

0.6 6.5
7.1

1.7

l.3

3.4

2.0

2,1

1.6

l.9

17.9 20.7

17.2

18 . 423 . 6

21 , l

0.7

1.0

1.2

Subtotal

54 . 7

Grandtotal

88.9 50 O 73 9 67 1 91.1

11 4 26 1 28 2 36.7

20 3 15 O 17 9 24.1
32.5 47 6 48 7 73 6

1.5

5.3

5.2

5.2

2.4

2.9

2.7

5,l

5.8

5.4

0.7

0.4

0,5

19.2

28 . 6 33 . 5 31 . 1

68 . 770.2 65 3 67.7

173

except Saman and Dajab6n, it showed a rapid increase
with age attaining to more than 40% in 5‑9 years age
class. In La Ci6naga, Ascaris prevalence further ele‑
vated to form a peak of about 70% in 10‑14 years age

Saman . Trichuris prevalence gradually decreased
thereafter but still remained at high level in elder groups

in these localities (Fig. 3). In Constanza/Jarabacoa, theprevalence in the youngest age class was 22%, but in‑class, while it decreased in the elder groups in El Valleand west‑central and southwestern localities (Fig. 2) . In

creased rapidly with age attaining a peak of 61.1% in 10‑14 years age class, then decreased rapidly again (Fig.

Saman3). In Dajab6n, the prevalence was generally low

and Dajab6n, no clear peak was observed in the

age‑related prevalence of Ascaris infection (Fig. 2) .

In Trichuris infection, the prevalence was already
50% or more in the youngest age class in the localities

except Dajab6n and Constanza/Jarabacoa, and formeda plateau through the next three or four age classes,
although it showed a decrease in 10‑14 years age class in

70

>

0.

throughout all age classes, forming a low peak in 10‑14
years age class (Fig. 3).

In El Valle and Saman , the prevalence of hook‑worm infection was about 20% and 15%, respectively, in
the O‑4 years age class, rapidly increased to form aplateau of more than 60% and 30%, respectiyely, in thenext three age classes, then decreased gradually but
again increased in the eldest' group (Fig. 4). In La
Ci6naga, the hookworm prevalence in the first age class
was only 1.4%, then increased to form a low peak (16%)
in 15‑24 years age class, then gradually decreased (Fig.
4) . In the west‑central, northwestern and southwestern

localities, the prevalence of hookworm infection was
20

o

r=* '
;v>

̲ *.‑"*. ='c‑ n;f55'
J :s ,'/ Q e:!
f59)very low throughout all age classes (Fig. 4).

( t/

‑ *..

r' :+

1 'QQ

* '
loQ

Figure 2 Age‑related prevalence of Ascaris lumbricoides
infection by locality in the Dominican Republic.

West‑central loc.: Constanza and Jarabacoa;
Southwestern loc. : Juancho, Oviedo, Pedernales

DISCUSSION
The helminths detected in the present study are of
simple life cycle except H. diminuta that requires anintermediate arthropod. Hato Mayor Prefecture where
El Valle belongs has been known as one of the endemicareas of schistosomiasis mansoni, and control measures
have been conducted from 1970 (Hillyer et al., 1986;
Vargas et al., 1987,1990) . Hillyer et al. (1986) proved

and La Cueva.
0

IQO

80

7Q

70
60
50
40
so
20

^SO
S
5Q

5e

t AQ

O
tG
tO

30
20

c

* ̲ /*'
n; 5' uv"'
()̲=0

r /'̲

I

;1;t' ̲ v .. ‑̲ *̲̲

li5 5

ss'

F1 (1 /) t Q

10

* p

.̲ /

i /SQ

I l)l
^ o ‑.

p

' ::

r;,

* '*

‑ ,
* .n;*
5 'j 6 ̲*¥' : 'n;1,‑

:/

'

*' "

..

n;'G:"
s:s'uv /). +oo.*
LI

l/ Q

! *,l 'oFigure 3 Age‑related prevalence of Trzchurrs trrchuara

Figure 4 Age‑related prevalence of hookworm infection

infection by locality in the Dominican Republic.

by lpcality in the Dominican Republic. West‑central loc.: Constanza and Jarabacoa; South‑
western loc.: Juancho, Oviedo, Pedernales and
La Cueva.

West‑central loc.: Constanza and Jarabacoa;
Southwestern loc. : Juancho, Oviedo, Pedernales

and La Cueva.

174

positive rate of 5.0% by radioimmunoassay in 1983 andVargas et al. (1990) detected schistosome eggs in 7.8%

hookworm infection may be the pollution of environ‑of inhabitants during the period from 1982 to 1987 in El
Valle. However, no schistosome egg was observed in thement with substances that may antagonistic to develop‑
ment of hookworm larvae. In urban slums, the environ‑

The cause of such unexpectedly low prevalence ofpresent material, suggesting that the rate of infection

ment is often contaminated with sewage containing

has been greatly reduced nowadays. Besides thesechemical substances including synthetic detergent andspecies, Taenia sp. has been recorded from Dominican

decomposed organic matter that would kill hatchedinhabitants, but its prevalence was very low (less thanlarvae of hookworms. Meanwhile, Ascaris and Trichuris

0.5%; Mackie et al., 1951; Vargas et al., 1987). The
absence of habit of eating raw meat or raw fish among
the Dominicans may be the cause of the low prevalenceof food‑borne cestode and trematode infections.
The present results showed marked differences in

eggs are more resistant in having thick shells, and their

the prevalence of soil‑transmitted helminthic infections

among localities (Table 1). One of the major causes ofthese discrepancies among the localities seems to be theclimatic difference. The northeastern region of the
Dominican Republic has large amount of rainfall, over
2,000mm/year, keeping the environment moist. Such
condition is especially suitable for larval development

and transmission of hookworms (cf. Schad and Warren,1990). The high hookworm prevalence in the northeast‑
ern region may be caused by this abundant precipitationand the low sanitation level. Meanwhile, the amount ofannual precipitation in the northwestern and southwest‑

ern regions is less than 1,000mm. Such dry condition
would inhibit development and survival of hookworm
larvae, as was reflected by the low hookworm preva‑
lence in these areas.

It has been well known that Ascaris eggs are moreresistant to desiccation than are those of Trichuris (cf.

infections may be enhanced by the crowded condition of
the urban slums.

Villa Duarte, Constanza and Jarabacoa sharedalmost same parasitological status characterized byrelatively low Trichuris and Ascaris infections (about
30% or less) and quite low hookworm prevalence (1essthan 5%) (Table 1) . In these areas, inhabitants are
generally wealthier than those in other localities except

Dajab6n, human population is less crowded, and/or the
latrines and drainage system are of adequate structure.
These conditions may reduce the opportunity of geohel‑minth transmission. In Dajab6n, where the living condi‑tion resembles those in Constanza and Jarabacoa, theprevalence of the orally‑transmitted geohelminth infec‑
tions was significantly lower than these localities(Table D. Possibly, much drier climate of Dajab6nmight also attribute to such low prevalence.

The parasitological status of the southwestern
localities, i.e. Juancho/Oviedo and Pedernales/La
Cueva, also resembled each other in having high preva‑
lence of Trichuris infection (more than 50%) , moderate
and low prevalence of Ascaris and hookworm infections,

Beaver et al., 1984). It was therefore unexpected that
the Ascaris prevalence in Saman and Las Cuchillas wasfound to be quite low, while the prevalence of Trichuris

respectively (Table 1). The low hookworm prevalence
seems to be due to the dry climate as in Dajab6n.

infection was rather high (Table l). At the present
time, no reasonable explanation on the cause of thisphenomenon is possible. However, it is suspected thatsome natural or artificial factors might be involved.
Such low Ascaris and high Trichuris prevalence has
been also recorded on some other Caribbean islands

and shortage of water may make contamination of the( Bundy,1986) , suggesting the presence of common cause (s)of this unbalanced prevalence of these orally‑transmit‑
ted geohelminth infections.
La Ci6naga is on the flood plain of the River Ozama
and the soil is usually moist. Moreover, inhabitants are

Meanwhile, the inadequate structure of the pit latrines
living environment with Trichuris and Ascaris eggs thatare more resistant against desiccation than hookworm
eggs and larvae.
Unlike the soil‑transmitted helminthic infections,the prevalence of protozoan infections was relatively
stable among the localities as shown above (Table 1).
This suggests that transmission of the intestinal proto‑zoans is not greatly influenced by the difference inclimate by locality. Infection of intestinal protozoans is

acquired by ingesting drinking water or foods

often barefooted and latrines are of quite inadequate
structure. Nevertheless, the hookworm prevalence wasless than 10% although Ascaris and Trichuris infections
were considerably prevalent (Table 1). Similar status
has been also reported in some urban slums of develop‑

contaminated with fecal material (cf. WHO, 1987). In
the surveyed localities, people often utilize unboiled
water for drinking and foods seem to be polluted with
protozoan cysts through dirty hands or flies. In La
Ci6naga, the people are residing in quite unhygienic

ing countries (Bundy et al., 1988; Ferreira et al.,1994).

condition, and thus transmission of protozoan cysts may

175

occur frequently as was reflected by the higher preva‑
lence of protozoan infections. Meanwhile, in Villa Duar‑te that is on the opposite bank of the River Ozama, theinhabitants are wealthier and live in much better condi‑tion than in La Ci6naga, and the prevalence of protozoan
infections was significantly lower. This fact may clear‑ly indicate that the paraiste prevalence is greatly in‑fluenced by the economical conditijon.
About 45 years ago, Mackie et al. (195D examined
l,139 sugar cane plantation workers in two southeastern
localities. The most prevalent helminth was hookworm(overall prevalence 59.2%) being followed by Trichuris

Dominican Republic.

(58.9%) and Ascaris (20.1%), and the most common
protozoan was E. coli (78.1%), being followed by

1 ) Arakaki, T., Hasegawa, H., Asato, R., Ikeshiro, T.,
Kinjo, F., Saito, F. and lwanaga, M. (1988): A new
method to detect Strongyloides stercoralis from humanEndolimax nana (47.7%) , Entamoeba histolytica (34.2%)
and lodamoeba buetschlii (26.3%). In 1977, Collins andEdwards (198D examined 137 fecal samples in thesouthcentral region and found that Trichuris infection

ACKNOWLEDGMEN TS
Smcere thanks are rendered to Lic. Dorcas
Paniagua, Centro de Gastroenterologia, Hospital <'Dr.
Luis E. Aybar", for her kind collaboration in the field
and laboratory works. This research was supported by
the Japan International Cooperation Agency.

REFERENCES

stool, Jpn. J. Trop. Med. Hyg., 16: 11‑172 ) Beaver, P. C., Jung, R. C. and Cupp, E. W. (1984):
Clinical Parasitology, 9th ed, Lea & Febiger, Philadel‑phia, 825pp

was commonest (prevalence up to 35.8%) being foll‑
owed by Ascaris (13.1%) and hookworm (8.8%) infec‑
tions. They observed only two protozoans, E. coli

3 ) Bundy, D. A. P. (1986) : Epidemiological aspects of
Trichuris and trichuriasis in Caribbean communities,
Trans. Roy. Soc. Trop. Med. Hyg., 80, 706‑718(24.8%) and G. intestinalis (0.7%). In 1980s. Vargas et4 ) ,Bundy, D. A. P., Kan, S. P. and Rose, R. (1988) : Age‑al. (1987) examined 1,025 inhabitants in Higuey, thecapital city of eastern‑most prefecture, and found that

Trichuris infection̲ was most prevalent (59%), being

followed by hookworms (20%), Ascaris (17%) andSchistosoma. mansoni (11.8%). Other helminthic infec‑

tions were less than 1% in total. The commnonest
protozoan was E. coli (33%), being followed by G.
intestinalis (5%) and E. histolytica (0.1%).

Because these studies were done in the localities
different from those in the present survey and the em‑
ployed techniques were also different, it is inappropriate

to compare their data directly with the present results.
However, it is suggested that the status of intestinal

parasitic infections, especially helminthic ones, haveremained almost unchanged during the recent five dec‑
ades in rural areas. Moreover, recent urbanization has
produced numerous slum dwellers, who are continuously
exposed to parasite infections as shown in the present
data of La Ci6naga. The intestinal helminthic infections
have been often considered as a too large problem to bechallanged by public health service because they occur
most commonly in the poorest communities of the devel‑
oping countries (cf. Savioli et al., 1992). However,recent advances of theoretical and practical studies
have provided realistic and cost‑effective options ofcontrol by chemotherapy (cf. Bundy et al., 1992; Guyatt
et al., 1995; Medley et al., 1993). Some appropriate
measures of intestinal parasite control should be taken

in order to improve the public health status in therelated prevalence, intensity and' frequency distrib, utionof gastrointestinal helminth infection in urban slumchildren from Kuala Lumpur, Malaysia, Trans. Roy.
Soc. Trop. Med. Hyg., 82, ,289‑294
5 ) Bundy, D. A. P., Hall, A., Medley, G. F. and Savioli, L.
(1992) : Evaluating measures to control intestinal para‑
sitic infections, Wld. Hlth. Statist. Quart., 45, 168‑179
6 ) Collins, R. F. and Edwards, L. D. (198D: Prevalence ofintestinal helminths and protozoans in a rural popula‑tion segment of the Dominican Republic, Trans. Roy.
Soc. Trop. Med. Hyg., 75, 549‑551
7 ) Ferreira, C. S., Ferreira, M. U. and Nogueira, M. R.
(1994): The prevalence of infection by intestinal para‑sites in an urban slum in S o Paulo, Brasil, J. Trop.
Med. Hyg., 97, 121‑127
8 ) Guyatt, H. L., Chan, M. S., Medley, G. F. and Bundy, D.
A. P. (1995) : Control of Ascaris infection by chemother‑apy: which is the most cost‑effective option? Trans. Roy.

Soc. Trop. Med. Hyg., 89, 16‑209 ) Hillyer, G. V., Galanes, M. S. de, and Mendez‑Silfa, A.

(1986) : Schistosomiasis in the Dominican Republic.
Detection of antibodies by radioimmunoassay, Bol.
Asoc. Med. Puerto Rico, 78, 477‑479
10) Mackie, T. T., Larsh, J. E. and Mackie, J. W. (1951) : A
survey of intestinal parasitic infections in the Dominican
Republic, Am. J. Trop. Med., 31, 825‑832
11) Medley, G. F., Guyatt, H. L. and Bundy, D. A. P. (1993) :A quantitative framework for evaluating the effect ofcommunity treatment on the morbidity due to ascariasis,
Parasitology, 106, 211‑221
12) Savioli, L., Bundy, D. and Tomkins, A. (1992): Intestinal

parasitic infections: a soluble public health problem,

176

Trans. Roy. Soc. Trop. Med. Hyg., 86, 353‑354

13) Schad, G. A. and Warren, K. S. (1990): Hookworm
Disease. Current Status and New Directions, Taylor &Francis, London, New York and Philadelphia, 438pp

14) Vargas, M., Abreu, E. and Matos, N. V. (1981):
Prevalencia y periodicidad de la filaria de Bancroft en

sangre diurna de la poblacion del Batey Ocho Central
Barahona, Republica Dominicana, Bol. Asoc. Med. Puer‑
to Rico, 73, 497‑502
15) Vargas, M., Perez, J. G. and Malek, E. A. (1987) : Schis‑tosomiasis mansoni in the Dominican Republic; preva‑
lence and intensity in the city of Higuey by coprologicaland serological methods, Trop. Geogr. Med., 39, 244‑250

16) Vargas, M., Malek, E. A. and Perez, J. G. (1990):
Schistosomiasis mansoni in the Dominican Republic;
prevalence and intensity in various urban and ruralcommunities, 1982‑1987, Trop. Med. Parasitol, 41, 415‑
41817) Vincent, A. L.. Gonzalvo, A., Cowell, B. C., Nayar, J. K.
and Uribe, L. (1987) : A study of Bancroftian filariasis in

the Dominican Republic, J. Parasitol., 73, 839‑840
18) WHO (1987): Prevention and control of intestinal para‑

sitic infections, WHO Tech. Rep. Ser. No. 749, 86pp

177

Jpn. J. Trop. Med. Hyg., Vol. 23, No. 3 (1995) pp. 177‑182

SEASONAL DENSITY AND MALARIA VECTORCOMPETENCE OF ANOPHELES MINIMUS
AND OTHER ANOPHELINES AT A SHALLOWVALLEY IN NORTH THAILAND
MASAHIRO TAKAGI*, WANNAPA SUWONKERD2, YOSHIO TSUDA1
CHIRASAK KAMBOONRUANG3, UDOM CHIPRALOP', SHUSUKE NAKAZAWA4HIROJI KANBARA' and YOSHITO WADA*
Received May 30, 1995/Accepted June 28, 1995

Abstract: Biting density of anopheline mosquitoes was monitored in both the rainy and dry seasons at 6
outdoor stations in two villages of north Thailand by 3 human and I water buffalo bait. A total of 19

Anopheles was collected. The most predominant species were An. vagus and An. annularis. They were
followed by An. hyrcanus group, An. minimus. An. aconitus. An. nivipes and An. kochi. The rest species
were not abundant. The fauna of Anopheles changed seasonally. An. minimus. An. aconitus and An.
barbirostris were abundant in the dry season, while An. maculatus sensu lato, An. kochi. An. tesselatus. An.

vagus. An. annularis and An. hyrcanus group were the rainy season Anopheles. The 'crude feeding index'
was relatively high in An. maculatus and An. minimus. They were followed by An. tesselatus and An.
splendidus, while that of An. vagus and An. kochi was less than 1/10 of An. minimus. An. minimus was
regarded as the most important vector. The biting density of An. minimus was higher at the peripheral areaof villages with scarce dwellings and rich vegetation. At stations with dense dwellings and adjoining to an
open field, the density of An. minimus was low, and the malaria risk was probably higher.

Key words: anopheline fauna, vector competence, shallow valley, north Thailand

INTRODUCTION
In Thailand a clear peak of malaria cases appears
in dry season, especially in November and December.
The prevalence of potential malaria vectors affects thisseasonality (Ismail et al., 1978; Harbach et al., 1987;

Rosenberg et al.. 1990; Gingrich et al.. 1990). Five
Anopheles were incriminated as the malaria vector in
Thailand (Ismail & Phinichpongse, 1980; Malikul, 1988) .

Among them, Anopheles minimus has been consideredas the primary vector at the mountain foot, forested
foothills and forest fringes because the species is abun‑dant at these areas, and preferably breeds in slow run‑ning streams located there (Ismail et al., 1978; Harbach
et al., 1987; Ratanatham et al.. 1988).

These areas also were one of the most delicate andunstable areas because man has actively touched thenatural environment by deforestation, human settle‑
ment, agricultural activities, and so on, and drastic
environmental changes have occurred in many places.
These changes must affect the bionomics of anophelinemosquitoes as suggested by Ismail et al. (1978) and Rao(1984). Therefore, it is quite necessary to re‑examine
the bionomics of anophlines occupying these areas. We
conducted an investigation of anopheline fauna both indry and rainy seasons from 1988 to 1990 in two villages
located in a shallow valley on the forest fringe, aiming
to clarify the seasonal density, the local distribution ofmajor potential vector species, and the risk of bite tohuman, all of which were important parameters in the1) Department of Medical Entomology, Institute of Tropical Medicine Nagasaki University Sakamoto 1‑12‑4, Naga !aki 852, Japan.
2) Malaria Center 2, Division of Communicable Diseases Control, Ministry of Public Health, Thai Government, Boonruangrit Road,
Amphur Muang, Chiangmai 50200, Thailand.
3) Research Institute of Health Sciences, Chiangmai University, Boonruangrit Road Amphur Muang, Chiangmai 50200, Thailand.
4) Department of Protozoology, Institute of Tropical Medicine, Nagasaki University Sakamoto 1‑12‑4, Nagasaki 852, Japan.
This study was partially supported by a grant under The Monbusho International Scientific Research Program (#63044112) , andby The Monbusho Overseas Research Fund.

178

malaria epidemiology. Results obtained from the inves‑tigation were reported in this paper. In discussion, we
also evaluated the vector competence of these species

the rainy season, and May to June, 1990 in the intermedi‑from the ecological point of view, and suggested an
epidemiological scope of malaria in the mountain footset of human and animal bait collections. In the humanbait collection, 3 collectors exposed their legs to mos‑area.

quito bite, sat outdoors, and caught all mosquitoes

MATERIALS AND METHODSTwo villages studied were in a shallow valley andsurrounded by forested mountains, ca. 450 m above thesea level, 98' 52' E and 19' 11' N, 50 km north fromate season in these villages. Adult collection was madeat 2 stations selected among 6 stations in one night by alanded to them by an aspirator with a 50 minute collec‑
tion followed by a 10 minute break from 18:OO to 24:OO.

In the animal bait collection, one water buffalo wastethered in a net (4 x 4 x 2 m) , which was similar to one

described by Service (1993), and one collector caught
mosquitoes landing in and out of the net using an aspir‑

Chiangmai city. Several clumps of dwellings wereator at every 15 minutes from 18:OO to 24:OO. The mutual

scattered within 4 km along an unpaved road. Reported
number of population was 1335 individuals during th
study period. Taking into the number and body size,

distance between stations was 300‑500 m.
The crude feeding index (Service, 1993) on humanwas calculated using the following 4 parameters; thehuman, water buffaloes and cows were main blood
sources for malaria vectors in the study villages

registered number of human population in the study
area [1335], the number of water buffaloes plus cows
counted by questionnaire [165], and the average num‑bers of anopheline mosquitoes caught by a human baitalthough dogs, cats, poultry and several swine were also

reared. There were two slow running streams, whichwere a main breeding place of An. minimus. The flatand by a water buffalo bait per half night. The risk ofpart of land was used as terraced rice fields or dwell‑ings. The lower part of slopes behind the flat area wasbite to human also was estimated by multiplying themainly occupied by rhychee orchards, while the upper
part was covered with the secondary forest.
A weekly population census for adult and larval
mosquitoes was made from December, 1988 to February,
1989 in the dry season, from June to November, 1989 in

Larval collection was made in 2 slow runningstreams targeting An. minimus. Four blocks each

crude feeding index by overall adult density.

covering 300 m of the streams were selected near the
adult collection stations. Twenty samples each com‑posed by 30 dippings were collected at each regular

Table 1 Environmental conditions of 6 stations where an anopheline mosquito collection was madeNo. ofStationGeneral topography

Vegetation

No. of waterDistance fromhouses buffaloes a stream& cows1

An end of village B

Rice field

Adjoining to a rice field
Distribution of dwellings; moderately dense

73

52

50 m
(stream B)

Sparse canopy
2

3
4

A pass between Station I and 3
Forest located behind plantations

Sugar cane plantation
Secondary forestoDistribution of dwellings; Sparse, in a forest
A bottle neck of a valley

Secondary forest

20

Adjoining to a wide rice field
Widest part of a shallow valley
Distribution of dwellings; moderately dense

Rice field

o

500 m
(stream B)

161000 m(stream A)

115

55

300 m
(stream A)

Sparse canopy
5Adjoining to a wide rice field
A center of village A
Distribution of dwellings; dense

Rice field

121

33

250 m
(stream A)

Sparse canopy
6

An end of village A

Rice field

Distribution of dwellings; Sparse, in orchards
Adjoining to a rice field

Rhychee orchard

Canopy composed mainly by orchards

8

9

200 m
(stream A)

179

(u'/

, ' o.')

1 , and the environmental conditions of the stations were

L

N

)

'& Station 1

BIOCk 1summarized in Table 1.

' ' ¥RESULTSStream A ,¥..¥̲̲ :.,The anopheline fauna and the seasonal density oftl̲on 2

adult sDuring the study period, a total of 19 species ofAnopheles was collected outdoors by human and water

¥

i¥:

;
so

i

t3

buffalo bait collections. They were An. hyrcanus group,An.' barbirostris Van der Wulp in the subgenus Ano‑pheles, and An. minimus Theobald, An. aconitus Donitz,
An. maculatus sensu lato, An. annularis Van den Wulp,

L

Station 4e l¥":

An. nivipes Theobald, An. varuna lyengar, An. kochi
Grassi, An. tesselatud Theobald, An. vagus Donitz, An.

Bl OCkn 4i

:+ ,

>

splendidus Koidzumi, An. jamesii Theobald, An. ste‑lphensi Liston, An. phillppinensis Ludlow, An. je porien‑
sis James, An. pallidus Theobald, An. culiclfacies Giles
and An. dirus Peyton & Harrison in the subgenus Cellia.

･.
Statlon 5/

BIOCk 5
IV

Stream B

l km

)]

;

The most predominant species were An. vagus andAn. annularis. They were followed by An. hyrcanusogroup, An. minimus. An. aconitus. An. nivipes and An.
hochi. The rest species were not abundant. The average
biting density (number of females per one bait per halfnight) of 12 dominant species, which were collected
more than 200 females during the study period, were

Block 6' Stat l

:

/

o

r :

Figure l Map showing 6 stations for adult collection
and 4 blocks for larval collection.

shown in Table 2.
In the dry season, An. minimus. An. aconitus. An.

census. A round dipper sized 13.0 cm in diameter and 7.

annularis and An. hyrcanus group were predominant,

5 cm in depth was used.

and the density of An. minimus caught by a human bait

Locations of 6 adult collection stations (1‑6) and 4
larval collection blocks (1, 4‑6) were illustrated in Fig.

was outstanding. They were followed by An. nivipes
and An. barbirostris. But the density of this second

Table 2 Average adult density (no./1 bait/half night) of 12 major anopheline mosquitoes collected by 3 human (H) and
1 water buffalo (B) baits in 2 mountain‑foot villages in north Thailand

SeasonDry

Rainy

Intennediate

Overall

Average density

No. of Bart

half nights mac
53 B
47 B+HH
53 B
48 B+HH
24 B
24 B+HH

130 B
ll9 B+H
H

min

aco

niv

48 . 954 . 829 . 4koc

ann var tes vag hyr bar spl Total

8.5
0.1
8.6

48 . 1281 . 128 . 1

3.5
0.1
3.6
6.4
0.5
6.9

464 . 874 . 4

5.7
0.0
5.7

3.6
0.1
3.7

2.3
0.1
2.3

7.4
0.0
7.4

43 . 627 . 70.5

0.3

44 . 1

12 . 5138 . 673 . 2

1.1

0.5

1.1

13 . 6

139 . 1

3.1

1.8

0.4

52 . 156 . 529 . 7

3.3
0.2
3.4

8.3
2.1

26 . 6

15 . 440 . 7133 . 8

0.7

1.6

0.3

2.9

10 . 3

2.7
0.3
3.1

27 . 317 . O

41 . O

136 . 7

0.0
0.0
0.0

7.7
0.6
8.3

0.7
0.0
0.7

1.1
0.0

1.6
0.2
1.8

0.1
0.0
0.1

0.5
0.0
0.6

0.0
0.0
0.0

0.0
0.0
0.0

3.5
0.0
3.5

0.9
0.0
0.9

0.8
0.0
0.9

0.1
0.0
0.1

17 . 124 . 723 . 6

23 . O

74 . 313 . 84.1

307 . 3

0.2

1.4

0.2

0.7

0.1

26 . 924 . 423 . 520 . 275 . 7

6.0
0.5
6.5

47 . 8

0.4

1.5
0.0
1.5

60 . 2

0.8

7.9
0.8
8.7

20 . 1

2.2

60 . 448 . 5

13 . 90.3
4.3

314 . 91.1

0.7
48 . 87.4
288 . 511.2
476 . O

0.9
18 . 1

7.6

min, An. minimus; aco, An. aconitus; niv, An. nivipes; mac. An. maculatus sensu lato; koc. An. hochi; ann, An. annularzs var An
varuna;tes, An. tesselatus; vag, An. vagus; hyr, An. hyrcanus group; bar, An. barbirostris; spl. An. splendidus.

180

abundant group was about a half of that of An.

and those at No. 2, 3 and 6 were low (Fig. 2c) . An.

minimus. Other anophelines did not over 10 individuals
per half night. The total anopheline density by humanand water baffalo baits was 288.5 individuals.
In the rainy season, predominant species changed.
An. vagus was strikingly abundant, though it was hardly

tesselatus were clasified as the fourth group which wascharacterized by the high frequency at station No. I and6, and low at station 4 and 5 (Fig. 2d) .
so(a)collected by a human bait. An. annularis also wascollected abundantly by a water buffalo bait. An.

!!laC.

‑‑‑‑koa‑‑‑hy!L

40

ll

30

maculatus. An. kochi. An. tesselatus and An. hyrcanus
group also were more abundant than in the dry season.
On the other hand, the biting densities of An. minimus
and An. aconitus in this season were evidently lower
than those in the dry season. However, the density ofAn. minimus in human bait collection was the second
highest. Total biting density by human and water baf‑
falo baits (476.0) was much higher in the rainy season

20
'‑lL

10

: ‑

/

/

/

/

/

o
50

min.

)
ll

40
30

than that in the dry season.

20

In the intermediate season, May and June, all

/

/

10

species were not abundant, and the anopheline mosquito

/

/

/

/

/

/

/

I‑

f

l,,

¥

‑ ‑ ‑spl.

/¥‑ ‑ ‑ ‑var.

¥

,f

f

¥

1'b
lb

¥

'b

'b
'b

¥
'b¥

,,

,

‑,,..

o

fauna was poor. An. minimus and An. maculatus were40

the only 2 species collected by a human bait.

‑‑‑niv.

(c)
'I

30

The difference of the adult density among stations
The frequency distributions of each species among
stations were calculated using the average densities(Fig. 2). The predominant species could be classified
into 4 groups depending on the frequency distribution.
In the first group including An. kochi. An. maculatus
and possibly An. hyrcanus group, a large proportion ofesamples were obtained at station No. 2 (Fig. 2a) , while2

in the second group of An. minimus. An. aconitus. An.

o '

20

...1,

.J¥‑.‑¥ .,,t10,,¥ ̲̲1'

/

8n!L

¥ 'L

lll‑"

‑ ‑ ‑ vag.

¥ "b,P

/

¥

o

40

(d)

‑‑‑‑tcs.
bar.

; 30

e':

varuna and possibly An. splendidus, the distribution wascharacterized by high frequency at station No. 3 and 6,

20
10

o

2

1

3

4

5

6

STATIONand by low frequency at No. 4 (Fig. 2b) . In the third

Figure 2 Proportion (%) of major anophelines (adult)group including An. annularis. An. nivipes and An.

at 6 stations.

vagus, the frequency at station No. 4 was the highest,

Table 3 Average larval density (no./30 dips) of anophelines at 4 blocks of 2 slow running streams and average adultdensity (no./1 bait/half night) of An. minimus at the nearest stations to the blocks

SeasonDry

Rainy

Parameter

Block and station
1

/

2

3

4

5

6

Average

Larval density

3.3

4

5

3.

3.8

% of An. minimus larvae

90 . 372 . 996 . 594 . 486 . 7% of young larvae

39 . 539 . o42 . 945 . 841 . 6Adult density of An. minimus

15 . 412 . 858 . 992 . 252 . 152 . 181 . 1

Larval density

0.9

o

o. 8

O. 3

O. 7

% of An. minimus larvae

86 . 773 . 460 . 838 . 567 . 5% of young larvae

59 . 656 . 850 .

70 . o58 . 8Adult density of An. minimus

9.5

11 .

10 . 3

7.9

10 . 312 . 7

6. 3

181

The larval population census in slow running streams

adult density shown in Table 2 enabled to estimate more

Results of the larval collection were summarized inTable 3. In the two slow running streams examined, therealistic risk of bite to human by a certain malaria

predominant species was always An. minimus. The

shown in Table 4. An. minimus showed the largest
value. This species was the most important malaria

proportion of this species among all anophelines col‑vector. The values calculated for each species were also

lected in the streams was more than 90% in the dry
season except at block 4. It decreased in the rainy

vector in the study area. The value of An. annularis

season especially at blocks 5 and 6 but more than 2/3 ofgreat abundance, this species should be dangerous in thesamples was still occupied by An. minimus on the
average. Other collected species were An. aconitus andrainy season. Both An. aconitus and An. maculatus
showed moderate values. The values of other species

An. hyrcanus group. The former was more in the drywere apparently smaller than these species.

was approximately 60% of An. minimus. Because of

season, while the latter was more in the rainy season.
The proportion of young larvae was higher in the rainyseason. The average larval density of An. minimus
among 4 blocks (only 3rd and 4th instar larvae weretaken into account) was nearly similar to each otherranging only 3.1‑4.5 per 30 dips in the dry season. It was

reduced to less than 1.0 in the rainy season, and its
reduction rate was larger from block I toward block 6.
The frequency distribution of larval population of thespecies among blocks did not coincided to that of adult

DISCUSSION
Anopheles fauna in the study villages was mainlycomposed of 19 species, and the species diversity anddensity were higher in the rainy season. Five Anopheles
were incriminated as the malaria vector in Thailand(Ismail & Phinichpongse, 1980; Malikul, 1988). Amongthese 5 species, 4 species except An. sundaicus werecollected in our study. An. dirus is the primary vector

in deep forests and mountains with serious malaria

population among stations.

The host preference and the risk of bites to humanThe human, baffalo and cow were considered as themain blood sources in the study villages. The host
preference of females was roughly evaluated by thecrude feeding index (Service, 1993) on human calculated

endemicity (Ismail et al.. 1974, 1975; Gingrich et al..
1990; Rosenberg et al.. 1990). Although this species ishighly anthropophilic, only one adult female was caught

by human bait in our study area located in a shallow
valley of forest fringes and surrounded by low moun‑tains. The scarcity of An. dirus in forest fringes was

METHODS, and was shown in Table 4. Because thealso confirmed by Ismail et al. (1978) . Therefore, theimportant malaria vectors in this area should be the rest

indices were rather small, all species encountered in thisof 3 species, An. minimus. An. aconitus and An.

study were found to be zoophilic. Among 12 species, An.

maculatus sensu lato.
The calculation of the crude feeding index and theby 4 parameters described in MATERIALS AND

minimus and An. maculatus showed relatively strong
preference to human. An. tesselatus and An. splendidus
followed the former 2 s ecies. An. kochi and An. v gus

were strongly zoophilic because the indices of these
species were less than 0.1 times of those in An. minimus

and An. maculatus.
Multiplying the crude feeding index by the overallrisk of bite to human suggested that An. minimus was
the most important malaria vector in the study area
because of both its relatively high density and highfeeding index to the human bait. The highest crude

feeding index in An. maculatus was noteworthy.
Although the crude feeding index was not large, An.

Table 4 Crude feeding index on human* and the risk of bite to humant in major anopheline mosquitoes
Parameter
Crude f. ix.

Ratio to min
Risk of bite

Ratio to min

min acoO . O110
1 . OOOO

O . 0043
O . 3953

niv mac koc
O . 0023
O . 2105

O . O1191 . 0786

O . OOIO
O . 0925

ann vartes

vag hyrbar

sp l

O . 0024

O . 0040

O . 0094

O . O004

O . O017

O . O013

O . 0078

O . 2186

O . 3623

O . 8570

O . 0398

O . 1587

O . 1211O . 7116
O . 0339

O . 1143

O . 2963

O . 1061

O . 0543

O . 1028

O . 0206

O . 1821

O . 0061

0.0611

O . 0264

O . 0846

O . 0185

1 . OOOO

O . 3580

O . 1833

O . 3470

O . 0695

O . 6146

O . 0205

O . 2062

O . 0891

O . 2856

O . 0626

min, An. minimus; aco, An. aconitus; niv, An. nivipes; mac, An. maculatus sensu lato; koc, An. kochi; ann, An. annularis; var, An.
varuna; tes, An. tesselatus; vag, An. vagus; hyr, An. hyrcanus group; bar, An. barbirostris; spl, An. splendidus.

'Density in human bait x water buffalo plus cow populations/density in buffalo bait x human population
tCrude feeding index X overall density

182

annularis was probably more important than An.

mosquito (Dipterea: Culicidae) habitats. J. Med.

aconitus in the study area because the species was rather

Entomol., 27, 1016‑1026
2 ) Harbach, R.E., Gingrich. J.B. and Pang, L.W. (1987):

abundant throughout the year. It should be noted that

An. annularis was regarded as an important malaria
vector in some localities in Sri Lanka (Ramasamy et al..
1992) and India (Rao, 1984).

Four types of frequency distribution of Anopheles

were observed in the study area. An. minimus wasabundant at a peripheral part of villages with scarcedwellings and rich vegetation. In contrast with this, thisspecies was not abundant at a part with dense dwellings.
These facts suggested that malaria risk transmitted by
An. minimus might be larger in scarcely populated areasuch as periphery of villages and between villages. It

was possibly due to more attacks by the species tolimited blood sources, and concentrated distribution to
the abundant resting places.
The topographic and vegetational characters of thestudy area, such as locating in a shallow valley withslow running streams and adjoining a forest fringe, arewidely observed in inland of southeast Asia. Drastic
environmental changes also have been occurred in thispart of Asia by deforestation, human settlement, agricul‑

Some entomological observations on malaria transmis‑
sion in a remote village in northwestern Thailand. J.
Am. Mosq. Cont. Assoc., 3, 296‑301
3 ) Ismail, I.A.H., Notananda. V. and Schepens, J. (1974) :Studies on malaria and responses of Anopheles
balabacensis balabacensis and Anopheles minimus to
DDT residual spraying in Thailand. Part 1: pre‑spray‑
ing observations. Acta Tropica, 31, 129‑1644 ) Ismail, I.A.H., Notananda, V. and Schepens, J. (1975) :Studies on malaria and responses of Anopheles
balabacensis balabacensis and Anopheles minimus to
DDT residual spraying in Thailand. Part 2: post‑spray‑
ing observations. Acta Tropica, 32, 206‑231
5 ) Ismail, I.A.H., Phinichpongse, S. and Boonrasri, P.
(1978) : Responses of Anopheles minimus to DDT resid‑
ual spraying in a cleared forested foothill area in central

Thailand. Acta Tropica, 35, 69‑82
6 ) Ismail, I.A.H. and Phinichpongse, S. (1980) : Monitoringsusceptibility of malaria vectors and suspected vectors

to pesticides in Thailand. WHO/VBC/80.775, 1‑167 ) Malikul, S. (1988): The current situation of the anti‑malaria programme in Thailand. Southeast Asian J.
Trop. Med. Pub. Hlth., 19, 335‑359

tural activities, and so on (e.g. Walsh et al.. 1993).
These changes must affects the bionomics of anopheline8 ) Ramasamy, R., De Alwis, R., Wijesundere, A. andmosquitoes, especially An. minimus as suggested byirrigation project in Sri Lanka: the emergence of Ano ‑pheles annularis as a major vector. Arn. J. Trop. Med.
Hyg., 47, 547‑553
9 ) Rao, T.R. (1984) : The anopheline of India. pp. 1‑518.
Indian Council of Medical Research, New Delhi

Ismail et al. (1978). A continuous monitoring of boththe environment and the vectors by a standardized
method is still necessary to yield more harmonious
vector control strategy.

ACKNOWLEDGMEN TS
We thank all field staff of Malaria Center Region 2
for their continuous help for the field survey.

REFERENCES
1 ) Gingrich, J.B., Weatherhead, A., Sattabongkot, J., Pila‑kasiri, C. and Wirtz, R.A. (1990): Hyperendemic
malaria in a Thai village: dependence of year‑roundtransmission on focal and seasonally circumscribed

Ramasamy, M.S. (1992): Malaria transmission at a new10) Ratanatham, S., Upatham, E.S., Prasttisuk, C., Ro‑janasunan, W., Theerasilp, N., Tremongkol, A. andViyanant, V. (1988): Bionomics of Anopheles minimus
and its role in malaria transmission in Thailand. South‑
east Asian J. Trop. Med. Pub. Hlth., 19, 283‑289ll) Rosenberg, R., Andre, R.G. and Somchit, L. (1990):
Highly efficient dry season transmission of malaria in
Thailand. Trans. Royal Soc. Trop. Med. Hyg., 84, 22‑28
12) Service, M.W. (1993): Mosquito Ecology, field sampling
methods, 2nd edition. Elsevier Science Publishers Ltd.,

Essex, UK
13) Walsh, J.F., Molyneux, D.H. and Birley. M.H. (1993):
Deforestation: effects on vector‑borne disease. Par‑
asitology, 106, S55‑S75

183

J pn. J. Trop. Med. Hyg., Vol. 23, No. 3 (1995) pp. 183‑187

SEASONAL AND SPATIAL DISTRIBUTION
OF 3 MALARIA VECTORS AT THREE

MOUNTAINOUS VILLAGESIN NORTH THAILAND

WANNAPA SUWONKERD , MASAHIRO TAKAGI', BOONSERM AMG‑UNG3
AND SOMSAK PRAJAKWONG
Received June 28, 1995/Accepted August 29, 1995
Abstract: Malaria vector occurrence in mountainous villages was monitored for 2 years in north Thailand.

Both larval and adult densities of Anopheles miniumus peaked in May or June and in November orDecember. Stable conditions in streams during these periods possibly favored the breeding of A n. miniumus.
Higher lalval density also was encountered in streams where ca. 3/4 of the water surface was sunlit, portions
with rapid currents and slow currents alternate, and the water waS clear. An. maculatus sensu lato peaked
in June or July, while An. dirus scarcely changed seasonally. The densities of the three malaria vectors werehigher in more mountainous villages.
Key words: malaria vectors, occurrence, mountainous villages, north Thailand

INTRODUCTION
In Thailand, the mortality due to malaria has
reduced from 351 per 100 . OOO population in 1947 to 3.9 incollect baseline data for more effective and economic
malaria vector control in rural areas. Results obtainedin the monitoring were reported in this paper withspecial attention to the environmental differences

1980, and to 2.1 in 1991 by an intensive nation wide
control program (Malaria Division, 1991). The vector
control, one of principal measures in the program,mainly depended on the residual spraying of DDT. Thismeasure could reduce the frequency of man ‑ vector
contact (Ismail et.al.. 1975). Although the residual
spraying of DDT was highly effective and practical inamong larval habitats.

areas with easy access, its applicability was limited inremote areas because of high per‑capita costs (Schliss‑phun and Lampang provinces. These were Ban Maemann, 1983) . Another problem in the DDT applicationis change in vector behavior (Ayurakit‑Kosol and Grif‑fith, 1963). Anopheles minimus avoided DDT‑sprayedwall surface, and malaria transmission continued byoutdoor biting (Ismail et.al.,1975) . Under these situa‑
tions, Iarval control should be considered, because An.

B) . Banpoung canton. King Toung Hua Chang district,and Ban Na‑Lam (village O . Sreamsrai canton. Sream‑
ngram district. Distances between neighboring two vil‑lages were ca. 3 km (Fig. D.
A monthly larval survey was co,nducted at 20 fixed
observation points, each in a sectibn of 100 m of aminimus prefers to breed only at a limited part of slow

stream passing through Village A and B, and at 15

running streams (Muirhead Thomson, 1940).
The vector occurrente was monitored for two years

points in another stream along Village C. Larval collec

in three village

diameter. Samples were kept separately by observation

with different slow running streams to

MATERIALS AND METHODSThis study was carried out from January 1987 toJanuary 1989 in three villages locating in mountainous

areas with two natural slow‑running streams in Lum‑

Bon Tai (village A) and Ban Mae Bon Noau (villagetion was made by two collectors using a plate of 9 inches in

1) Malaria Center Region 2, Department of Communicable Diseases Control, Ministry of Public Health, Thai Government,
18 Boonruangrit Road, Muang District, Chiangmai 50200,, Thailand
2) Department of Medical Entomology, Institute of Tropical Medicine, Nagasaki University, 1‑12‑4 Sakamoto, Nagasaki 852, Japan
3) Research Section, Malaria Division, Department of Communicable Diseases Control,
Ministry of Public Health, Thai Government, Soi Phrabumratnaradoon, Nonthaburi 11000, Thailand

184/
̲f hc cowHuman
baned adutt cettectlon slte
f 1
baned adutt conectton slter.fl ' ' stream! ¥¥̲̲' pathway r !i;e( er7//eej''Il"b Main roadIJ

edb e ehcLei ,,ozLleL

ec e¥e' L
e ¥cF

T! t:Vilta9e ̲̲̲̲, .̲) o'i)'feoo'JLl,Lili a'
Vtlta9eAl‑̲̲'JL
JL ;dbL/LJELO̲̲h'Lcc!c!
ceLl/"J 'e‑'liJL1(1I¥¥Ll Pi x r5
T' 1P
E '
/1 IJ JLJl

LJL L

u Itl sl r,/ ; :r!ec'¥ r)r ‑¥¥¥ ,,op p c r'l"'?1 d ca leoo ̲ j'Q

T:a e¥ceL

f' s'̲̲o̲̲'14leeJ r

h'* 4/ /̲J/1/ ' ¥j /C 'Loo 1 ‑‑al el$j

3,3:‑160 !1)

/ l̲

(

' 700

Figure I Sketch map of the study area'

POintS in Small VialS With 4% fOrmalin sOlution, and fied to ' d: " All ObServations were made between lO:OO
identified to SPecies under a miCroScope in the labOra‑ and 14:OO'

tOry'
Human and COW baitedmonthly
adult
COllection waS madeIn every Survey, preSence or abSence of Water at thefor two nights between 18:OO ‑ 24:OO at a 'fixed
fixed points was recorded, and the percent of water

station in each village. Two human and one cow werecoverage (100 x no. of boints with water / no. of points

used as baits.

examined) was calculated. The monthly precipitation
record was collected from the nearest meteorologicalquitoes by an aspirator. Fifty minutes collection and 10

Human baits sat outdoor, and collected landing mos‑of f ice.

minutes break were repeated hourly. A cow bait was

The light condition, velocity of water current andwater clearness at each fixed point were recorded bydirect observation. The light condition was classified

tethered inside a gauze cage shown by Service (1993) ,and one collector collected mosquitoes resting on wallsof the cage by an aspirator every 15 minutes.

into 3 classes ( + , d: and ‑ ) . One m2 of water surface

was examined at each point, and if the water surface
was fully sunlit, the point was classified to ' + '. If half‑

sunlit and half‑shady, the point was classified to ' d: ',RESULTS AND DISCUSSION

and ' ‑ ' was for the fully shady point. The velocity of

The seasonal prevalence of An. minimus larvae ateach village is shown in Fig. 2. The average larval

water current was recorded following Muirhead Thom‑density fluctuated similarly in 3 villages with two peaksson (1940) . A table tennis ball was released at upperedge of a certain point, and the velocity was measured

in the early rainy season, and the second peak in Novem‑

by observing the ball drifting downstream. When theball moved: 2.0, 2.0‑0.3 and 0.3‑0.0 feet / second, thepoint was classified to ' + ' (fast) , ' d: ' (slow) and ' ‑ '(stagnant) , respectively. The water clearness also wasclassified into 3 classes. If a part of the bottom of a

stream was clearly seen up to 30 cm in depth, theclearness of the point was classified to ' + ', and, if notseen and smelled, the point was classified to ' ‑ '. A pointwith the bottom not seen and without smell was classi‑

in a year. The first peak was observed in May or Juneber or December at the onset of the dry season. The
water coverage of the streams, being affected by theseasonal pattern of precipitation, increased just before
the first peak of the larval occurrence, and decreased
just after the second peak of it as shown in Fig. 3. These
facts suggested that the amount and pattern of precipi‑

tation decisively influenced the seasonal occurrence ofAn. minimus. Too much rain in the middle of the rainyseason possibly lowered the larval density by flooding or185fast currents of water, while too little rain late in the dry

C. The water current was slower in a stream alongseason also lowered it by reducing the available larval

Village A than that along Village B Iocating upstream.

habitat. Stable water conditions in slow‑running

In another stream along Village C, points with andwithout fast water currents were subequal in number.
The stream water was the clearest at a section of a
stream along Village C, followed by a stream along

streams provided by moderate amounts of rainfall is arequisite to the occurrence of abundant An. minimus.
The average of An. minimus larvae 1100 dips was
1.29 (SD 2.13), 2.22 (SD 2.8D and 3.71 (SD 8.79) in
Village A, B and C, respectively (Table D. As to thelight condition, a stream along Village A was the mostsunlit. It was followed by another stream along Village

Village B and A. Therefore, it was suggested that thelarval density was high in such a stream as in Village C,

where ca. 3/4 of the water surface was sunlit, portions
with fast and slow water currents appeared alternative‑
:

IOO
l
l

90

"L

l
l

N‑

Rantall

300

A

I t t

I ‑ ‑ ‑B
I

I

I
I

80

t

ll

70

!̲

O

60

>
O
O

50

I

,

t

t

i

I

30

ISO

>

I

l

I

N

I

I

l

l

l

I

l

I

t

l

I

t

,

t

l

I
l

I

I

l

so

l

I
I

.=

f

I

I

10

100
I

I

20

200

I

l

,

I

40

l

t

l

I

e!:

l

I

l

l

aF!,(

,

t

t

t

a

t

I

I

ll

I

l
l

,

2so

I

l

b
'b

I,t

o

o

f

.

,
MONTII

Figure 2 Seasonal density of 4th instar larvae of An. minimus in slow‑running streams along
3 study villages.
30

A‑ ‑ ‑B

25

C

20
eD

*e

8* 15
: I

5
Z

10

l I

l

l I

I

I

s

l

t
l

ld'

55

,

l

l

.

l

t
l

I
I

t

l

N

o

l

ll I

l

' I

l‑
I,t
II,

,t

,

:8

i

l

,

' N I ,･ lb,p

cp:D< 80e> : yea ,MowrH

Figure 3 Monthly amount of rainfall at the nearest meteorological office (histogram) and thewater positive rate at fixed sampling points (lines) in study streams.
,

186

Table l Average density of 4th instar An. minimus larvae (number per 100 dips) ,and average proportions (%) of 3 classes of light condition, water
current and clearness at 20 Iarval sampling points in 3 villages during 25

months.
Village

Larval densityA+i

1 . 29B+2 . 22C

Sunlight Water current

Class

+

3 . 71

Clearness

95 . 2

3.5

4.3
0.5

29 . 515 . 364 . 972 . 6

11 . 91.5

8.959 . 297 . 363 . 923 . 8

1.2

24 . 517 . O

48 . 945 . 999 . 550 . 65.1

0.4

46 . 50.5
0.0

Table 2 Average number of females per half night and the proportion (%) of 3
major malaria vectors (parenthesize) collected by 2 human plus 1

cow

baits during 25 months.

VillageAn. mmimus

An. dirus

An. maculatusA

5.7(14. 5)

1 . O (2 . 6)

6 . I (15 . 5)

39 . 5 (100 . O)

BC

24 . 2 (13 . 7)

2 . 3 (1 . 3)

48 . O (27 . 2)

176 . 3 (100 . o)

20.2( 4. 6)

2 . O (O . 5)

64 . 2 (14 . 5)443 . O (100 . o)ly, and the water was fairly clear.

Three potential malaria vectors, An. minimus, An.
dirus and An. maculatus sensu lato, were collected in 3
villages by humans and cow‑baited adult collections.
The average number of females per half night and the
proportion of these species during the study period is

Total Anopheles

summarized in Table 2. All of these species were moreabundant at Village B and C, both of which were more
mountainous than Village A. However, the proportion ofthese vector species to the total Anopheles was different

among villages. The proportion of An. minimus and An.
dirus rather decreased from Village A to C in this order,soo

I1‑I n. mikim,s450‑ll‑Al,. d lus‑It‑A,,. macl I h, s

400
3SO

300

250
200
OF11 ISO

IOO

so

o

/l

;

J
elD<

1

0> ; elD<
z:'10

MONTll:Figure 4 Seasonal density of females of 3 dominant malaria
vectors collected by human and cow baited half‑night collection.

̲. I

ll‑

eQ

5
o

,

187

while that of An. maculatus sensu lato was highest at

transmission on focal and seasonally circumscribed

Village B.

mosquito (Diptera: Culicidae) habitats, J. Med.

The seasonal change in adult density of 3 malaria
vectors is illustrated in Fig. 4. An. minimus showed a

Entomol., 27, 1016‑l026
3 ) Ismail, I. A. H., Notananda, V. and Schepens, J. (1974):

clear bi‑modal pattern with peaks in May‑June andStudies on malaria and responses of Anopheles

October ‑ November. This seasonal pattern correspond‑
ed to that of the larval population of the species de‑scribed in the above. In contrast with An. minimus, An.

spraying in Thailand. Part 1. Pre‑spraying observations,maculatus sensu lato was abundant during the rainy

balabacensis and Anopheles minimus to DDT residualActa Tropica, 31, 129‑1644 ) Ismail, I. A. H., Notananda, V. and Schepens, J. (1975):

season. The seasonal pattern of occurrence in our study

Studies on malaria and responses of Anopheles

areas agreed with the observations made in Wang Thonbalabacensis and Anopheles minimus to DDT residual
spraying in Thailand. Part 2. post‑spraying observa‑

district, Pitsanuloke province and in Muaklek district,
Saraburi province (Ismail et al., 1974, 1975, 1978) for

An. minimus and in Pakchong district, Nakhon Rat‑

tions, Acta. Tropica, 32, 206‑231

5 ) Ismail, I. A. H., Phinichpongse, S. and Boonrasri, P.

chasima province and in Mae Tang district, Chiangmai(1978) : Responses of Anopheles minimus to DDT resid‑

province (Upatham et al. 1988; Takagi et al., 1995) forual spraying in a cleared forested foothill area in central

An. maculatus. Different seasonal prevalence from ours
also was reported in An. minimus (Ratanatham et al.,
1988; Leemingsawat, 1989; Gingrich et al., 1990; Takagi

6 ) Leemingsawat, S. (1989) : Field trials of different traps

et al., 1995) in different provinces of Thailand, even if

at a foot‑hill basin in Kanchanaburi, Thailand, Jpn. J.

the seasonal precipitation pattern was nearly similar
each other.
Our study lightened favorite conditions in the larval

habitat on breeding of An. minimus. However, above‑
mentioned various seasonal prevalence of the species

Thailand, Acta Tropica, 35, 69‑82
for malaria vectors and epidemiological investigations
Sanit. Zool., 40, 171‑179

7 ) Malaria Division (199D: Annual Report of Ministry of

Public Health. pp. 1‑101, Ministry of Public Health,Thai Government, Bangkok.
8 ) Muirhead Thomson, R. C. (1940) : Studies on the behav‑

still requests a more analytical study focusing to theiour of Anopheles minimus. Part 1; the selection of therelationship , among the rainfall pattern, the larval hab‑breeding place and the influence of light and shade, J.

itat quality and the malaria vectors occurrence. The

Mal. Inst. India, 3, 265‑294

study will provide to predict the seasonal abundance and9 ) Ratanatham, S., Upatham, E. S., Prasittisuk, C., Ro‑to evaluate the feasibility of larval control of thejanasunan, W., Theerasilp, N., Tremongkol, A. andViyanant, V. (1988): Bionomics of Anopheles minimuss pecies.

Owing to its low density, the seasonal prevalence ofAn. dirus in the study area was indefinite.

and its role in malaria transmission in Thailand, South‑

east Asian J. Trop. Med. Pub. Hlth., 19, 283‑289

lO) Schlissmann, D. J. (1983) : Malaria : Cycle of mosquito
control, Residual spray and ???, Mosquito News, 43, 413

ACKNOWLEDGEMEN T‑418

We are indebted to Dr. Udom Chitprarop, the for‑11) Takagi, M., Suwonkerd, W., Tsuda, Y., Kamboonruang,mer director of Malaria Center 2, for his encouragement

C., Chipralop, U., Nakazawa, S., Kanbara, H. and Wada,

during the study. We thank all collectors for their
excellent work throughout the study period and Prof.
Yoshito Wada for critical reading the manuscript. We
also thank Dr. Yoshio Tsuda for valuable comments.

Y. (1995) : Seasonal density and malaria vector compe‑

tence of Anopheles minimus and other anophelines at ashallow valley in north Thailand, Jpn. J. Trop. Med.
Hyg., 23, 151‑156
12) Upatham, E. S., Prasittisuk, C., Ratanatham, S., Green,

C. A., Rojanasunan, W., Setakana, P., Theerasilp, N.,

REFEREN CES

Tremongkol, A., Viyanant, V., Pantuwatana, S. and

1 ) Ayurakit‑Kosol, L.and Griffith, M. E. (1963): Progress

Andre, R. G. (1988): Bionomics of Anopheles maculatus

toward malaria eradication in Thailand, Proc. 9thcomplex and their role in irnalaria transmission in

Pacific Sci. Congr., 17, 122‑136

Thailand, Southeast Asian J. Trop. Med. Pub. Hlth., 19,2 ) Gingrich, J. B., Weatherhead, A., Sattabongkot, J., Pila‑kasiri, C. and Wirtz, R. A. (1990) : Hyperendemic
malaria in a Thai village: dependence of year‑round259‑269

189

Jpn. J. Trop. Med. Hyg., Vol. 23, No. 3 (1995) pp. 189‑196

BLACK FLIES (DIPTERA= SIMULIIDAE)

FROM HONG KONG= TAXONOMIC NOTESWITH DESCRIPTIONS OFTWO NEW SPECIESHIROYUKI TAKAOKAl, DOUGLAS M. DAVIES2 AND DAVID DUDGEON3
Received July 28, 1995/Accepted August 24, 1995

Abstract: Light‑trapped adult specimens of Hong Kong Sirnuliidae, together with a few pupae and larvae
collected from streams were examined. Eight species were recognized, consisting of twlo new species andsix newly recorded ones. A11 the eight species belong to the genus Simulium Latreille s. l. and are further
placed in three subgenera: Nevermannia Enderlein (1 sp.), Gomphostilbia Enderlein (2 spp.) and Simuliums. str. (5 spp.). Descriptions of the two new species are given.

No black‑fly species has been reported so far from
Hong Kong. In this paper we record six known species
and describe two new species, chiefly based on adultspecimens collected using light traps by one of us (D.
Dudgeon) . Collecting methods and a description of thecollecting site (Tai Po Kau Forest Stream) were given
by Dudgeon (1988) . Specimens obtained by other inves‑or 14 vertical columns and 15 or 16 horizontal rows oflarge facets. Clypeus brownish black, whitish pruinose,
covered densely with whitish yellow pubescence inter‑
spersed with several dark hairs. Antenna composed oftigators and held in Bishop Museum, Hawaii, U.S.A.,

ments; proportional lengths of 3rd, 4th and 5th segments

have been examined also.
The morphological features and terms used follow
those of Crosskey (1969). The systematic placement isdone at subgeneric and species‑grdup levels according
to Takaoka and Davies (1995a) .
Type specimens of two new species will be deposit‑
ed at Bishop Museum, Hawaii, U.S.A.

1.0 : 1.1 : 2.8 ; sensory vesicle (Fig. 1) small, 0.15 x as

Family Simuliidae Newman
Subfamily Simuliinae Newman
Tribe Simuliini Newmann

2 + 9 segments, brown with scape, pedicel and base of Ist

flagellar segment yellow; Ist flagellomere elongate, ca.

2.0 X as long as 2nd one. Maxillary palp with 5 seg‑long as 3rd segment, with an opening near distal end.
Thorax. Scutum brown, with trace of 3 fine longitudinal
vittae, densely covered with bright golden yellow recum‑
bent pubescence; scutum entirely whitish pruinose on

anterodorsal surface when illuminated dorsally andviewed from front; also largely white pruinose on
prescutellar area in certain angle of light. Scutellum
brown, with bright golden yellow pubescence and sev‑

eral dark long marginal hairs. Postscutellum brown,

Genus Simulium Latreille s. l.

whitish pruinose, bare. Pleural membrane bare. Katepis‑
ternum longer than deep, with dark hairs and pale ones.
Legs. Foreleg: coxa yellow; trochanter dark yellow to

Subgenus Gomphostilbia Enderleinbrown; tibia brown with outer median surface largely
somewhat pale; tarsus brown to dark brown; basitarsus

1. Simufium(Gomphostilbia) dudgeoni Takaoka &Davies, sp. nov. Figs. 1‑15

DESCRIPTION. Male. Body length ca. 3.0 mm. Head.
Slightly wider than thorax. Upper eye consisting of 13

slender, ca. 8.0 X as long as its greatest width. Midleg:coxa dark brown; trochanter and femur brown; tibiabrown with base yellow; tarsus dark brown with basal
1/3 to l/2 somewhat pale. Hind leg (Fig. 5) : coxa
brown; trochanter yellow to dark yellow; femur brown

1 ) Division of Medical Zoology, Oita Medical University, Hazama, Oita 879‑55, Japan2 ) Department of Biology, McMaster University, Hamilton, Ontario, L8S 4K1, Canada
3 ) Department of Ecology & Biodiversity, The University of Hong Kong, Pokfularn RoadIL

Hong Kong

190

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Male and female adults of Simulium (Gomphostilbia) dudgeoni sp. nov. I & 2, 3rd maxillarypalpal segment (1, c71 ; 2,calcipala (a, b) (5,cr'; 6,f;･:q:.,.' ' .'.,e :.:..

' ::p..:a" :t' 6
Figures I ‑ 1 5

a

,1 ,

‑,

) ; 3,); 7,

fronto‑ocular area; 4,cibarium; 5 & 6, hind legs withclaw; 8, crl gentalia in situ (ventral view; a, coxite; b, style;c, ventral plate) ; 9, style (ventrolateral view); 10 & 11, ventral plate (10, Iateral view; 11, endview) ; 12, paramere; 13, median sclerite; 14,
genitalia in situ (ventral view; a, 8th sternite;b, anterior gonapophysis; c, gental fork; d, spermatheca; e, paraproct; f, cercus) ; 15, paraproct(a) and cercus (b) (lateral view) .

d

191

with base yellow; tibia brown with basal 1/5 to 114
yellow, gradually darkened toward distal tip; tarsus

brown in ground color, shiny, whitish grey pruinose,brown with basal 1/2 and a little more of basitarsus andbrown with whitish yellow pubescence and long erectbasal 2/5 of 2nd segment whitish yellow; basitarsus
moderately inflated, spindle‑shaped, tapering at bothends, ca. 4.8 x as long as wide, ca. 0.75 x as wide as
hind tibia which is subequal in greatest width to femur.

with trace of 3 faint, fine longitudinal vittae. Scutellum

dark hairs along posterior margin. Postscutellum
brown, whitish grey pruinose, bare. Pleural membranebare. Katepisternum dark brown, with numerous hairs,
longer than deep. Legs. Foreleg: coxa white; trochanter

Calcipala (Fig. 5a) well developed, slightly shorter thanyellow; femur brown; tibia yellowish brown on basal

wide. Pedisulcus well developed. Wing. Length 2.0 mm.
Costa with spinules and hairs. Subcosta bare. Ba:sal
portion of radius fully haired. Hair tuft on stem vein

3/4, brown on distal 1/4, with outer surface largely pale

brown. Abdomen. Basal scale brown, with fringe oftrochanter yellow; femur brown; tibia yellowish whiteon basal 1/3, brown on rest, posterior surface of basal

dull brown hairs. Dorsal surface of abdomen brownish
black, covered with dark hairs; segments 2, 5‑7 eachwith a dorsolateral pair of shiny, whitish pruinose

on basal 3/4; tarsus dark brown; basitarsus slender, ca.
7.7 x as long as its greatest width. Midleg: coxa brown;

2/3 Iargely white shining when illuminated; tarsus
brown with basal 1/2 or a little less of basitarsus yellow‑

patches; those on segment 2 widely connected in middle.

ish white. Hind leg (Fig. 6): coxa brown; trochanter

Genitalia (Figs. 8‑13). Coxite nearly rectangular inyellow; femur brown; tibia yellowish white on basal l/3

ventral view. Style ca. 0.8 x length of coxite, somewhat
wider at base in posterolateral view, gradually tapered

or 1/2, brown on apical 1/2, though its border not welldefined, posterior surface of basal 2/3 Iargely white
shining when illuminated; tarsus brown with basal 2/3 oftoward apical tip, gently curved inward, with apicalspine. Ventral plate transverse, ca. 0.5 x as long as
wide, distinctly widened posteriorly, with nearly straight

posterior margin in ventral view; ventral plate wid, ely

produced ventrally along posterior margin as seen inlateral view; ventral plate moder tely covered withmicrosetae on ventral and posterior surface; basal arms

somewhat converging; Paramere with I distinct par‑ameral hook and several medium ones. Median sclerite

basitarsus and basal 1/2 of 2nd segment white; basitar‑sus slender, parallel‑sided, ca. 6.8 x as long as wide.
Calcipala (Fig. 6b) well developed, slightly shorter thanwide. Pedisulcus well developed. Hind femur and tibia
ca. 1.9 x and 1.6 x as wide as hind basitarsus, respecti‑
vely. Claws (Fig. 7) each with a large basal tooth 0.51 x

as long as claw. Wing. Length 2.0 mm. Costa with

Female. Body length ca. 2.5 mm. Head. slightly narr‑

spinules as well as hairs. Subcosta fully haired. Hair
tuft of stem vein fell, then coloration unknown. Basal
portion of radius fully haired. Abdomen. Basal scale

ower than thorax. Frons dark brown, whitish grey

dark brown with fringe of pale yellow hairs. Dorsal

pruinose, densely covered with whitish yellow iecum‑
bent pubescence interspersed with a few dark hairs;

surface of abdomen brownish black; tergite of 2nd seg‑ment whitish pruinose, tergites Df segments 6‑8 shiny.
Genitalia (Figs. 14 & 15) . Sternite 8 bare medially,

thin, plate‑1ike, weakly sclerotized.

frontal ratio 1.7 : 1.0 : 3.1. Frons‑head ratio 1.0 : 5.7.

ments 1.0 : 1.0 : 2.7 ; 3rd segment not so enlarged, sensory

with ca. 18 dark macrosetae on each side. Anterior
gonapophysis thin, membraneous, nearly triangular inshape, rounded posterointernally, covered densely withmicrosetae and a few short setae near anterior border;
inner margin well sclerotized. Genital fork of usual
inverted‑Y form, with arms folded medially, bearing
inner margins slightly converging posteriorly. Para‑proct moderately produced ventrall.y, 0.5 x as long as
wide. Cercus ca. 0.5 x as long as wide, with posterior

vesicle (Fig. 2) oblong, ca. 0.4 x as long as 3rd segment,border rounded when viewed laterally. Spermathecawith a medium opening near distal end. ,Maxillary

ellipsoidal, well sclerotized except a small area nearlacinia with 13 or 14 inner and 14 outer teeth. Mandiblewith ca. 28 small inner teeth and 8 outer ones. Cibarium

tubal juncture; internal setae absent.

(Fig. 4) medially forming low, rectangular, moderately
sclerotized plate folded forward from posteri6r margin;cibarium medially with heavily sclerotized longitudinal

TYPE SPECIMENS. Holotype c l , slide mounted,
HONG KONG: New Territories, Tai Po Kau Forest

Fronto‑ocular area (Fig. 3) well developed. Clypeus
dark brown, whitish grey pruinose, densely covered withwhitish yellow pubescence interspersed with several
dark hairs. Antenna composed of 2 + 9 segments, brown‑
ish black except scape, pedicel and base of Ist flagellar

segment yellowish; Ist flagellomere somewhat elongate,ca. 1.6 x as long as 2nd one. Maxillary palp with 5
segments; proportional lengths of 3rd, 4th and 5th seg‑dark band with dorsal end forked. Thorax. ScutumStream, Iight trap, by D. Dudgeon, 2. VI. 1983. Allotype, slide mounted, same data as holotype. Paratypes: 2

192

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s; '* {,.*It':f )' *1 "'!7; i, ,, , :' ':; ',,+･+ :i¥i(ji!{!';4!,j;',;={+ il';‑::

l',',//v .././" "
.s

.',.

22

17 18

20

Figures 16‑23 Male adult of Simulium (Simulium) taipokauense sp. nov. 16, 3rd maxillary palpal segment;
17, hind basitarsus & 2nd tarsomere; 18, calcipala; 19, genitalia in situ (ventral view) ; 20,style (medial view) ; 21 & 22, ventral plate (21, Iateral view; 22, end view) ; 23, median sclerite.

(7! , same data as holotype; I c , same data as holotype hind tibia which is pale on the basal 3/5 and by the wider
except 14‑15.II.1984; I c71 , same data as holotype except fore basitarsus (L : W = 5.7 : 1.0) (Davies and Gy6rk6s,
12‑13.IV.1984.
1987). This new species is also similar to S. (G.) sp.

collected from Taiwan by having the spindle‑shaped
male hind basitarsus, though somewhat wider (L : W =REMARKS. The species name dudgeoni is given after 4.2 : 1.0) (Takaoka, unpublished data) . The male of S.
Dr. D. Dudgeon, The University of Hong Kong, who ( G.) sp. differs by the coloration of the hind tibia with

DISTRIBUTION. Hong Kong.

collected this species.

the basal 1/2 whitish.

This species is assigned to the ceylonicum‑group of

the subgenus Gomphostilbia by the inflated male hind 2 . Simulium ( Gomphostilbia) asakoae Takaoka &basitarsus (Fig. 5). The spindle‑shaped male hind
Davies, 1995
basitarsus separates this species from most known Simulium ( Gomphostilbia) asakoae Takaoka & Davies,
species of this species‑group, of which basitarsus iswedge‑shaped. S. (G.) ceylonicum from Sri Lanka has

1995b : 53‑58.

an inflated, spindle‑shaped male hind basitarsus but it is
The male and female adult specimens collectedmuch wider (Length : Width = 3.4 : 1.0) (Davies and from Hong Kong show almost the same characters of S.
Gy6rk s, 1987). The female of S. ( G.) ceylonicum ( G.) asakoae recently described from West Malaysia

differs from the present species by the coloration of the (Takaoka and Davies, 1995b) . This species belongs to193subgenus Nevermannia Enderlein

the ceylonicum‑group by having the inflated, wedge‑
shaped, male hind basitarsus, which is remarkably enlar‑
ged in this species: that is, 3.3 >< as long as its greatest

3 . Simulium (Nevermannia) aureohirturm

width, subequal to or slightly wider than the hind tibia

Brunetti, 1911
Simulium aureohirtum Brunetti, 1911: 283‑88 (male) ;Edwards, 1934: 134‑37 (female, pupa and larva) .
Simulium (Nevermannia) aureohirtum: Ogata, 1956: 61‑
62; Ogata, 1966: 129; Crosskey, 1988: 459; Takaoka
and Roberts, 1988: 194‑95; Crosskey and Lowry,
1990: 204; Takaoka and Davies, 1995b: 85‑86.
Simulium (Eusimulium) aureohirtum: Puri, 1933: 1‑7;
Ogata and Sasa, 1954: 325; Ogata, Sasa and Suzuki,
1956: 73; Crosskey, 1973: 423; Takaoka, 1976: 170

and 1.4 x width of the hind femur. The hind basitarsus
and tibia of the male are white on the basal 1/2 or alittle less, and brownish on the rest. The hair tuft on thebase of the radial vein of both sexes is yellow. The maleis also distinctive by the small number of enlarged facets(i.e., 10 vertical columns and 12 or 13 horizontal rows oneach side) .

SPECIMENS EXAMlNED. I c71, HONG KONG: New‑71; Takaoka, 1979: 382‑84; Datta, 1983: 225;

Territories, Sai Kung, Iight trap, by W. J. Voss & Hui
Wai Ming, 15. X. 1964; I
1965; I, I

f, 12. II. 1965; I, 8.III.1965; I ( !, 17.III.1965; I

17. XI. 1964; 2
XU:. 1964; I, 24. II.

l, 2. N. 1965; I (71,

1‑13. Simulium (Eusimulium) tuaranense Smart, 25. XI. 1964; 3 c?1, 9. XU:. 1964; I , 10.

and Clifford, 1969:40‑43. Syn. by Crosskey, 1973.

l, 18. Xu:. 1964; I , 4.1.1965; I , 11. I. 1965;l (71, 15‑16. I. 1965; I c l, 22. I. 1965; I c71, 23. I. 1965; 2l,

25. I. 1965; I',

30. I. 1965; Il, 26. I. 1965; Il, 29. I. 1965; I, 10

Simulium (Eusimulium) philippinense Delfinado, 1962:
47‑62. Syn. by Takaoka, 1983.

, 10. V . 1965 (all pinned, Bishop Museum).

l (71, Tai Po Kau, Malaise trap, by Lee Kit Ming & Hui
Wai Ming, 1. VI. 1964; I , I l, by W. J. Voss & Hui
Wai Ming, 6. VI. 1964; I

1 , 9Takaoka and Suzuki, 1984: 11‑12; An, 1989: 182.
Eusimulium aureohirtum: Orii, Uemoto and Onishi, 1969:, 11. VI. 1964; 7l, 16. VI. 1964; I, 15. VI. 1964;, by W. J. Voss, 20. N. 1964;

The morphological characters of female and maleadult specimens from Hong Kong agree with the rede‑scription of this species given by Takaoka (1979) andTakaoka and Roberts (1988) except that the scutellum, by W. J. Voss & Hui Wai Ming,of the present male specimens bears golden yellow long

, I (7!, by W. J .Voss, 26. VI. 1964; 1

hairs instead of brown hairs. This species is a member of, by W. J. Voss & Hui Wai Ming, 27. VI. 1964; I , 2l, 30. VI. 1964; I , 6 l, by Lee Kit Ming & Hui Wai

the ruficorne‑group defined by Crosskey (1969) , and is
widely distributed iri the Oriental Region and also parts

Ming, 2‑6.VU:. 1964 ; 6of the Palaearctic Region. This is the first record of this

1 l, 22. VI. 1964; I
22‑24. Vl. 1964; 3

1964; 2, 19 l, 3‑4. ul. 1964; I c71, 6‑8.VI.

, 17. VU:. 1964; I l, W. J. Voss & Hui Wai Ming,, 17. V. 1965; I , 3. VI. 1965; I , 14. VI.

species from Hong Kong.

, 15. VI. 1965; 4 , 17. VI. 1965; 4 , 28. VI. 1965;

SPECIMENS EXAMlNED. 2 c71 , HONG KONG: New

4. N. 1965; I
1965; I1 , 2. VU:. 1965; I, 5. VU:. 1965; I , 12. VU:. 1965; I c71,

Territories, Sai Kung, Iight trap, by W. J. Voss & Hui

15‑17. VU:. 1965 ; I, 26. VI. 1965; I , I c71, 27.vuL1965;

Wai Ming, 8. X. 1964; 2 , 2 c l, 9. X. 1964; I , 3. Xl.

l, 13. VW:. 1965; I, 29. VI. 1965; I

1965; I
3

, 2

, 4

l, 20. vul. 1965 ; I , hand net, 24. VUI. 1965;

l, 2. D(. 1965; I, 3.D(. 1965; 2

1 c 1, 9. D(. 1965 ; I , I

Museum) . I, hand net, 19. vul.
, I c7f, 6. IX. 1965;l, 15. D(. 1965 (all pinned, Bishop, pinned, New Territories, Castle Peak,by W. J. Voss, 29.ul.1964 (Bishop Museum) . I

l , Tai Po

Kau Forest Stream, 10. V. 1975, by D. Dudgeon; 5 c l ,light trap, 2. VI. 1983 ; I, I

l , 17‑18.1.1984; 26

15. II. 1984; I (71, 7‑8. 111. 1984; 2l, 14‑

l, 28‑29. 111. 1984; 6!,

12‑13. IV. 1984 (all in alcohoD. I , pinned, Lantau
Island, Trappist Monastary near Silver Mine Bay, by W.
J. Voss, 22. VI. 1964 (Bishop Museum) .

1964; I2

, 17. Xl. 1964; I, I XU:. 1964; I, 2. xn:. 1964; I c71, 9. XU:. 1964; 2

1 c l, 20‑21. I. 1965; I

29. I. 1965; I, 2.

I. 1964;, I cf!, 18. Xl:. 1964;, 25. I. 1965; I c?1, 26. I. 1965; I (rl,, 6 c l, 30. I. 1965; I, 12. II. 1965; I c7t, 15.

II. 1965 (all pinned, Bishop Museum) . 2 c, Tai Po Kau,

Malaise trap, by W.J.Voss & Hui Wai Ming, 16.VI.1964;
1 (71, 27. VI. 1964; I, 30‑31.VI.1964; I c l, 20. vm:.1965; 1

c l , 23. Vul. 1965; I, by Lee Kit Ming & Hui Wai Ming,

1. D(. 1965 (all pinned, Bishop Museum) . 2, Lantau
Island, Trappist Monastary near Silver Mine Bay, by W.
J. Voss, 22. vn. 1964 (all pinned, Bishop Museum) . 2,
Tai Po Kau Forest Stream, Iight trap, by b. Dudgeon, 2.
VI. 1983; I immature larva, 18. XI. 1976 (all in alcohoD;

DISTRIBUTION. Hong Kong (new record) , West

1 immaure larva (in alcohoD , Sam A Chung Stream, by

Malaysia.

D. Dudgeon, 18. Xll. 1979.

194

DISTRIBUTION. China, Hong Kong (new record) ,India, Japan, Java, Philippines, Sabah, Sri Lanka, Sul‑awesi, Sumatra, Taiwan, Thailand, West Malaysia.

Hind leg: coxa brown; trochanter white; femur dark
yellow or yellowish brown with base white and distal
cap brown; tibia dark brown with base white; tarsus
dark brown with a little less than basal 1/2 of basitarsus

Subgenus Simulium Latreille s. str.

4 . Simulium (Simulium) taipokauense Takaoka,
Davies & Dudgeon sp. nov. Figs. 16‑23

and of 2nd tarsomere white; basitarsus (Fig. 17) wedge‑
shaped (in some specimens spindle‑shaped) , expanded,
3.7‑4.2 x as long as its greatest width, and its width
ratio to that of hind tibia and femur 1.00:1.04‑1.12:0.96‑

l.08 (n=4) ; calcipala (Fig. 18) small, slightly shorter

DESCRIPTION. Male. Body length 2.8‑3.5 mm. Head.

than wide, not reaching pedisulcus; pedisulcus distinct at

As wide as or slightly wider than thorax. Upper eye
consisting of 19 horizontal rows and 19‑21 verticalcolumns of large facets. Clypeus dark brown, whitish

basal 1/3 of 2nd tarsomere. Wing. Length 2.3‑2.4 mm;costa with spinules and hairs; subcosta bare; basal

grey pruinose, iridescent when illuminated, cbvered withdark brown. Abdomen. Basal scale dark brown with

10ng dark hairs along both lateral margins. Antennacomposed of 2 + 9 segments, dark brown to brownish

long dark hairs. Dorsal surface of abdomen dark brown,with dark hairs; segments 2, 5‑7 each with a pair ofblack with scape, pedicel and base of Ist flagellar seg‑silvery iridescent areas dorsolaterally, those on segment

ment pale; Ist flagellomere elongate, ca. 1.8 x as long as

2 connected broadly in middle. Genitalia (Figs. 19‑23).

2nd flagellomere. Maxillary palp composed of 5 seg‑

Coxite in ventral view nearly quadrate; style elongate, 1.

ments, proportional lengths of 3rd, 4th and 5th segments
1.0 : 1.1 : 2.8; 3rd segment of normal size, with small,round sensory vesicle (Fig. 16), 0.18 x length of 3rd

segment. Thorax. Scutum dark brown, with whitepruinose and iridescent pattern differing with angles oflight: when illuminated posterodorsally and viewed dor‑sally scutum shows an ant, erior pair of narrow rectangu‑

portion of vein R entirely bare; hair tuft at base of R

45 >< as long as coxite, spatulate ventrodorsally, without

terminal spine; style with prominent, black basal protu‑
berance pointed dorsally, its anterior margin furnishedwith several small spines. Ventral plate in ventral view

broad, saddle‑shaped, with rounded posterior margin,setose on ventral surface, with thick basal arms diver‑lar white iridescent bands separated medially by darkged; ventral plate with a small, nipple‑shaped, baremedian process; ventral plate weakly dentate alongbrown area (width a little narrower than 1/3 'of that ofposterolateral margins. Parameres wide, each with

scutum) , and a wide white iridescent posterior spot
occupying ca. 2/5 of scutum; when illuminated dorsallyand viewed anterodorsally anterior bands fade and areslightly widened toward apical tip.

several distinct hooks. Median sclerite club‑shaped,

Femals. Pupa and Larva. Unknown.

replaced by subanterior pair of white iridescent bands ofsimilar size; when illuminated in certain angle of light

TYPE SPECIMENS. Holotype c7' , slide mounted,

these anterior and subanterior bands on each side arefused forming a large iridescent spot on each shoulder,which extends from anterior corner to wing base along
lateral margin in a wide band which is widely connected
to a posterior spot; scutum uniformly covered with pale
pubescence, interspersed with long dark erect hairs on

HONG KONG: Tai Po Kau Forest Stream, Iight trap, 14‑15.II.1984, by D. Dudgeon. Paratypes: 14 c l, same data
as holotype; I c7, , same data as holotype except 17‑18. I.

1984; I c 1, same data as holotype except 12‑13. N. 1984.

DISTRIBUTION. Hong Kong.

prescutellar area. Scutellum dark brown, whitish
pruinose, with several dark erect hairs and pale pubes‑

REMARKS. The style of male genitalia of this newcence. Postscutellum dark brown, whitish pruinose,
iridescent under certain lights, bare. Pleural membrane

species bears an elongate basal protuberance (Fig. 20) ,a character commonly seen in all species of the multis ‑and katepisternum bare. Legs. Foreleg: coxa white;

triatum‑group and in some species of the griselfrons‑

trochanter and femur dark yellow; tibia brown with angroup of the subgenus Simulium s. str., defined by
Takaoka and Davies (1995a) . The pale midleg of thisspecies resembles that of S. (S.) ufengense reported
from Taiwan (Takaoka, 1979) and S. (S.) fuzhouenseouter surface largely pale and white iridescent in light;

tarsus brown; basitarsus moderately dilated, 5.6‑6.3 x
as long as wide. Midleg: coxa dark brown; trochanter,
femur and tibia yellow, tibia with a large white sheen on

posterior surface; tarsus brown except basal 4/5 ofbasitarsus and base of 2nd tarsomere yellowish white.

from Fujian, China (Zhang and Wang, 1991) , both, of thegriselfrons‑group. However, the basal protuberance ofthe style is much longer than those of these two known

195

species, and the ventral plate is saddle‑shaped, with anipple‑shaped median process (Fig. 19) in this new

This species belongs to the nobile‑group and is separat‑
ed from other related species by the simple female claw,

differs from all the other species of the griselfrons ‑groupand three inflated pupal gill filaments per side. The
pupa of S. (S.) shirakii Kono and Takahasi, 1940 from
Taiwan is similar to that of this species (Takaoka,

and all the species of the multistriratum‑group by theshape of the ventral plate. This species is tentatively

lack of a larval stagd of S. (S.) shirakii. Future studies

assigned in the griselfrons ‑group.

may clarify the identity of the Taiwanese species.

5 . Simulium (Simulium) sakishimaense Takaoka,

SPECIMENS EXAMlNED. Pharate

1977
Simulium (Simulium) sakishimaense Takaoka, 1977: 197‑
201; Takaoka, 1979: 398; Takaoka and Suzuki, 1984:

8 immature larvae (in alcohoD , collected from a stream,

species but is flat and quadrate in shape, without any
median process in the latter two species. This speices1979) , but a detailed comparison is impossible due to thewith pupal skin,

HONG KONG: Tai Po Kau Forest Stream, 28.X . 1976,
by D.Dudgeon; 2 mature larvae (in alcohoD , Lam Tsuen

39‑40; An, 1989: 188.

River, by D.Dudgeon, 28. X . 1976.

The female, male and pupal specimens collected

DISTRIBUTION. China (Fujian, Yunnan) , Hong Kongfrom Hong Kong almost agree with the original descrip‑tion given by Takaoka (1977) . The upper eye of males(new record) , India, Thailand.

from Hong Kong shows somewhat more facets: i.e., 19

7 . Simulium (Simulium) quinquestriatum Shiraki,

horizontal rows and 18 vertical columns (15 horizontal
rows in the type specimen) . This species belongs to the1935 Stilboplax 5‑striatum Shiraki, 1935: 27‑33.
Simulium (Stilboplax) 5‑striatum: Ogata and Sasa, 1954:

multistriatum‑group redefined by Takaoka and Davies

330‑31; Ogata et al., 1956: 77‑78; Orii et al., 1969:1‑(1995a). This is the first record of this species from

13.

Simulium (Simulium) quinquestriatum: Anonym., 1974:

Hong Kong.

192; Takaoka, 1977: 205‑09; Takaoka, 1979: 396‑99;

SPECIMENS EXAMlNED. 2 c71 , HONG KONG: New

An, 1989: 187.

Territories Sai Kung, Iight trap, by W. J. Voss & Hui, 30. I . 1965;

The adult female, male, pupal and larval specimens

1 c7', 8.II.1965; I (7f, 24.II.1965 (all pinned, Bishopfrom Hong Kong almost agree with the redescription

Museum) . I (7f, Tai Po Kau, hand net, by Lee Kit

given by Takaoka (1979) . This species belongs to the

Ming & Hui Wai Ming, 26. VI. 1965;, I cf', Malaise trap,
27. VI. 1965; I , Malaise trap, 29. VI. 1965; I , Iight

striatum‑group redefined by Takaoka and Davies

trap, 14. Vlll. 1965; 2

female separates this species from most other related

Wai Ming, 26. I . 1965; I c71, 27. I . 1965; I, Iight trap, 2. D(. 1965; I cfl, handnet, 6. IX . 1965 (all pinned, Bishop Museum) . 3, 13 crl(1995a) . The haired basal section of the radial vein in thespecies of the striatum ‑group.

Tai Po Kau Forest Stream, Iight trap, by D. Dudgeon, 2.
VI. 1983; I c71, 20. ul. 1983; I , , I c7!, 17‑18. Xl. 1983; 2 c7',

SPECIMENS EXAMlNED. 2

17‑18. I. 1984; 2

New Territories, Sai Kung, Iight trap, by W. J. Voss &, 15 (71, 14‑15. 11 . 1984; I

reared frompupa, 2 pupae, 2 pupal exuviae, 10. V. 1975 (all in

Hui Wai Ming, 2. N. 1965; I

alcohoD . 2 pupae (in alcohoD , Sam A Chung Stream, by

1964; I

Dudgeon, 18. XU:. 1979.

1, 18. Vn. 1964; I, 2 c71, 30. XI. 1964; I

1965; I

, 10 crl, HONG KONG:, 7. VU:. 1964; I', 1. IX. 1964; I, 18. VU:.

', 8. X. 1964;, 15. I .1965; I ( l, 15‑16. I .

, 20‑21. I . 1965; I c7t, 25. I . 1965; 2, 4 cf', 30.

DISTRIBUTION. China (Fujian) , Hong Kong (newI . 1965 (all pinned, Bishop Museum) . I

record) , Japan, Taiwan and Thailand.

Kau, Iight trap, by Lee Kit Ming & Hui Wai Ming, 1. D( .
1965 ; 13

6 . Simulium (Simulium) nodosum Puri, 1933
Simulium (Simulium) nodosum Puri, 1933: 813‑17;
Takaoka, 1984:33; An, 1989: 187.

, 39

, hand net, 3. VI. 1965; I (7f , 28.VI.

, 3‑4. VU:. 1965; I‑17. Vu. 1965; 2

vm. 1965; I

The pharate female and pupa agree with the origi‑

l, 2. DC. 1965; 2 cfl, 3. IX. 1965 (all pinned,

Bishop Museum) ; I
1965; I

, I (71 , Tai Po, I c71, 12. XII. 1965; 2 c?1, 15, 27. XU:. 1965; I, 13. VUI. 1965; I, 29. VI. 1965; I, 19. WU:. 1965; Il, 9.

, 20.Vgl.

1965; 2 c71, 23. vm:. 1965; I , 4 l, 27. vul. 1965; I el, 31. vul.

nal descriptions given by Puri (1933) and the larvae also

1965; I

conform to the redescription given by Datta (1988) .

3 d , 3. IX. 1965; 2, 5 (7!, 1. IX. 1965 ; 13

, 41 c71, 2. IX.1965; Il, 4. IX. 1965; Il, 15. XI. 1965; I

,

,

196

20．皿．1965（allMuseum）．1♀，3♂，Tai

preliminary

identifications

PoKau，1ighttrap，byWJ．Voss＆HuiWaiMing，4．Iv．

preserved

specimens

1965（all

MissC．Aoki，Division

Forestpinned，Bishop

pinned，Bishop

Stream，light

Museum）．5♂，Tau

trap，byPo

Kau

D．Dudgeon，2．VI．1983；1♀，2♂，17−18．L1965；1♀，1♂，14−15．II．1984；14♂，12−

13」V．1984（all2matureinlarvae（allalcohol）．6pupae，3pupalinalcohol），Brides

University

andZoology，The

Dr、Denis

and

their

help．DMD

isgrateful

D．

ities

provided

by

the

Kong

Sz硲z6h露Rubtsov，1963：525−26．

S勉％1勉吻（S吻％1伽吻）s備励露：Takaoka，1977：209−13；
Takaoka，1979：395−96．
S物z％∬鰯zη嘘翅2ηsθOgata，1966：123−30．Syn．byTa−

kaoka（1977）．

Simuliidae（Diptera）of

record

of

to

this

the劾66名os％ηz−group．This

species

from

Hong

is

the

first

EXAMINED．1♂，HONG

Po

Stream，light

Dudgeon；1♂，same
1984

（both

in

data

space

of

the

Hong
and

of

Depart−Kong，forcopyingfacil・

Biology，McMaster

KONG：Taitrap，14−15．II．1984，by

as

the

formerD．

except12−13．N．

alcohol）．

re−classification

Africa

Sぎ吻z

Sri

and

its

E総ぎ

あz

Lanka．Descriptions

zz4伽郷andoftheislands，Bull．Br．

new

a

Hong

Go

of

Kong

forestψhos〃16毎of

periods

streamofaquatic

L

in

the

genus

insects

from

Macronematinae

Stenopsychidae（Trichoptera），
on

black

flies

of

Islands，Japan（Simuliidae；Diptera）III．On
the

the

Insects，10，61−68

5）Takaoka，H．（1977）：Studies
ofSimuliidae

speciesz，Can．J．ZooL，65，1483−502

4）Dudgeon，D．（1988）：Flight（Hydropsychidae）and

Kong．

SPECIMENS
Forestof3）Davies，D．M．＆Gy6rk6s，H．（1987）：The

AquaticKau

toblackfly fromthe Terai ofWest Benga1，India（Diptera：
Simuliidae），Opusc．Zool．Flumin．，31，1−8（Diptera）of

The two males collected from Hong Kong agreewith the description given by Takaoka（1977）．This
belongs

thankMus．（Nat．Hist．）Entomo1．Suppl．，14，195p
2）Datta，M、（1988）：S吻π伽窺（S．）αs醜歪spec．nov．，asubgenera

speciesfor

Department

1）Crosskey，R．W．（1969）：A〃z

alcohol−

REFERENCES

record），Japan，Korea，Taiwan．

1づz

and

University．

8．Sε肌配」伽肌（Sε肌μ」如肌）8鵬配1蹴Rubtsov，1963zzHill，formerly

University

exuviae

DISTRIBUTION、China（Fujian，Yunnan），Hong

S才pinnedofMedicalZoology，OitaMedical

Pool，byDudgeon，22．D【．1977．

（new

to

the

collectedbefore1983．We

ment

of

of

subgenus

S吻zz

」づz

z

the

Nanseisix

species

Latreille，JPn．J．Sanit．ZooL，

28，193−217
6）Takaoka，H．（1979）：The black flies of Taiwan（Diptera：

Simuliidae），Pac．Insects，20，365−403

DISTRIBUTION．China（Yunnan），Hong

Kong（newrecord），Japan，Kofea，Taiwan．

7）Takaoka，H．＆Davies，D．M．（1995a）：The black flies（Diptera：Simuliidae）of Java，Indonesia，Bishop Mus．
Bu1L

Entomo1．inpress．

8）Takaoka，H．＆Davies，D．M．（1995b）：The

ACKNOWLEDGEMENTS

sity

We

are

gratefulSA

forloaning

by

one

of

to

the

specimens

Bishopadditional

Museum，Hawaii，U．
tous（D．Dudgeon）．Mrs．Helen

black

flies

（Diptera：Simuliidae）ofWestMalaysia，KyushuUniver−thosecollected

Gy6rk6s

madePress，inpress．

9）Takaoka，H．＆Roberts，D．M．（1988）．Notes on black．
flies（Diptera：Simuliidae）from Sulawesi，Indonesia，
Jpn．J．Trop．Med．Hyg．，16，191−219

Suwonkerd，W．，TAKAGI，M，Amg−Ung，B．and
Seasonal

ThereeandSpatialMountainous

Distribution

Villages

Takaoka，H。，Davies，D．M．，and

Black

in

North

Notes

with

Vectors

at

Thailand……一…・…・……

一・

・183−187

Dudgeon，D．

Flies（Diptera：Simuliidae）from

Taxonomic

PRAJAKwoNG，S．

of3Malaria

Descriptions

of

Hong

Kong：

Two

New

Species・・189−196

September1995

VOL23NO．3

CONTENTS
Original article
Gomez E．，Andrial，M．，Hosokawa，A．，Nonaka，S．and Hashiguchi，Y．，
0ral Treatment of New World Cutaneous Leishmaniasis with Anti−Malarial

Drugs

in

ECUADOR：A

Preliminary

Clinical・151−157

Tria1一Higa，N．，Iwanaga，M．，Utsunomiya，A．，Kuyyakanond，T．，

Shithivong，N．，Wasito，E．B．，Toma，C and Yamashiro，T．
Dmg Sensitivity of励吻6hol召惚and Sh忽61めSpecies in theWorld

一159−164

与Nakasone，N．，Iwanaga，M．，Wasito，E．B．

Lindawati Alimsardjono，L．and Widiyatno，T．V．
The Frequency of Healthy Carriers with Enteropathogenic
Bacteria

−A

in

study

Surabaya，Indonesia

inanElementary

Schoo1一Miyata，A．，Hasegawa，H、，Castro，M
Intestinal，The

Parasitic

Dominican

Infections

Republic

in

……一

and
Some

一…

一165−167

Baron，R．
Rural

and

Urban

Areas

of
一169−176……・……・………………一・……・……一……

Takagi，M，Suwonkerd，W．，Tsuda，Y．，Kamboonruang，C．，Chipralop，U．，Nakazawa，S．，

Kanbara，H．and
Seasonal
and

Other

Wada，Y．

DensityandAnophelines

Malariaata

VectorShallow（Contents

CompetenceofValleyNorthcontinued

oninreversedAηoφh6」6s〃lo％珈郷

ofThailandthis……………一…・…………177−182

cover）