Jpn. J. Infect. Dis., 52, 1999

Laboratory and Epidemiology Communications

EpidemiologlCal Studies of an Outbreak of Paratyphoid Feverin the Shima Area of Mie Prefecture
Akira Sugiyama*, Yoko Nakan0, Yoshito Iwade, AkinoriYamauchi, Nakao Sakurai,
Osamu Nakayama, Yukitaka Yamamotol, Masayuki Nakatsul , Yoko Mori1 ,YoshiyaKishidal, Takashi Oidal, Norichika H. Kumazawa2,
JunTeraJlma3and Akiko Nakamura3
Mie PrejTectural Institute of Public Health and Environmental Sciences,

Sakura‑cho 3690‑1, Yokkaichi, Mie 512‑1211,

1Division offlealth and Welfare, Mie Prefecture Government,Tsu, Mie 514‑8570,

2Tropical Biosphelle ReseaTICh CenteTT, UniversityofRyukyu,
Nishihara‑cho, Okinawa 903‑0213 and3Department of Bacteriology, National Institute of lnjTectious Diseases,Shinjuku, 7Tokyo 162‑8640

Communicated by Yutaka Miyazaki(Accepted January I 2, 2000)

On 14 December 1993, Mie PrefecturalInstitute of Public

consumption. There were 17 patients in Mie, five in Osaka,

Health and EnvironmentalSciences was informed by Osaka
Prefecture of four cases of paratyphoid fever. Allthe patients

two in Shizuoka, and one each in Hyogo, Aichiand Yamaguchi
Prefectures (Figs･ I and 2)･ Salmo.nella Paratyphi A washad used the same pension K in the Shima area of Mie

isolated in all of the patients. The majority of the isolates was

Prefecture･ Then reports of paratyphoid cases came sequen‑that of phase type 2 (Fr2). No secondary infections, such as
those occumng in family members, were reported･From November to December 1993, 407 persons usedtially･ A totalof 27 paratyphoid cases were reported from theend of December 1993 to early January 1994. Twenty‑fourpatients used pension K and two used pension U. All of thepatients had eaten raw oysters there. One patient was a fisher‑pension K and 140 persons used pension U. All clients of themanwho had never used eitherpension. He retained part ofhis haJVeSt inthe sea near the harbor of the village forpersonal

infection. All of them were healthy except patient #9, who

two pensions were investigated for possible paratyphoid
had been diagnosed as having a common coldand who also

Fig. 1. Geographicaldis廿ibution of patients.

*Corresponding author: Fax: +81 ‑593129‑3∝叫253Jpn. J. Infect. Dis., 52, 1999

Date ofDiagnosis

Ingestion* : Asymptomatic patients↓Pension KPension U@ Fisherman
Fig･ 2･ ChronologICaldistribution of illness in patients‑dates of food ingestion and final diagnosis･

L

1

2

3

4

5

6

7

8

9of all workers in pensions K and U were examined severaltimes･ S･ Paratyphi A was not detected in any of the samples.

LFoods conserved in refrigerators in both pensions wereexamined for g. Paratyphi A on 15 and 24 December, andnone of the refrigerated samples were positive.

All the patients ingested raw oysters. The oysters had been
kept ln Sea Water in a harbor about I km away from the village
where the two pensions were l∝ated. The water draining Into

the harbor or surrounding the oysters kept there was not

infected with sewage. Nevertheless, we were able to isolate

S. Paratyphi A Fr2 from one in two mud samples collected
on 13 January 1994 near the place wherethe causative oysters
were kept. The PFGE pattems of the sea water isolate and theother patient‑derived isolates (Fig. 3) were identical. Further

isolation trials fromthe same or other places wereunsuccessfd.
This study demonstrated the power of PFGE in epidemi0‑
10gical analysis (I). The data suggest that S. Paratyphi Afirstcontaminated the sea water and the mud in the harbor, andthen the oysters became contaminated. The phage‑type mostprevalent in Japan was Frl (2). Fr2, which was associatedwith the present outbreak, was reported to be more prevalentFig･ 3･ PFGE analysis of isolates･ Bacteria were placed in wells onthe
top of Incert Agarose Gel, lysed with lysozymeand treated within Thailand, Indonesia, and other Southeast Asian countries

proteinase K for proteolysIS andthen with BlnI restriction enzyme
for DNA digestion･ The gel electrophoresis was performed withthe present outbreak, was not resident in thisarea but probably

BioRad CHEF‑DRII under the followlng COnditions: voltage, 6 V/

a strain imported from these other countries. It should tnt noted

cm; pulsetime, 5‑50 see; temperature, 17.C; duration, 23 h. Lane I:

that the affected area is a famous tourist resort in Japan. In

isolate fromanunderwater mud sample fromthe harbor. bnes 219:

addition, many people from the SoutheastAsia come to work(2). It is quite possible that theぶ. Paratyphi, which caused

isolates from patients. L: ladder marker.

in this area.

REFERENCES

had dia汀hea at the time of investigation･ Stool specimens(patient #13) were fd血nd to be positive for S. Paratyphi A;

1. Tenover, F. C., Arbeit, R. D., Goenng, R. V., Mickelsen,
P. A., Murray, B. E., Persing, D. H.and Swaminathan,that patient was, however, asymptomatic. Stool specimens

B. (1995): Interpreting chromosomal DNA restriction

were collected from 344 persons. Samples from one person

254

Jpn. J. Infect. Dis., 52, 1999
pattems produced by pulsed‑field gel electrophoresis:

Control Division, Ministry of Healthand Welfare ( I 996):

Criteria for bacterialstrain typing. J. Clin. Microbio1., 33,

Typhloid fever and paratyphoid fever, Japan, January

2233‑2239.

I 994‑September I 996. Infect. Agents Surveillance Rep･ ,2. National Institute of HeaIthand Infectious Diseases

17, 296'‑297'.

255