bluuebunny/crossref_metadata_2025 huggingface dataset:
Fas / FasL system, IL‐1β expression and apoptosis in chronic HBV and HCV liver disease
Authors: Bortolami M. , Kotsafti A. , Cardin R. , Farinati F.
Published: March 2008

Summary.  The Fas / Fas‐ligand (FasL) system is an important death signal pathway in the liver. An enhanced local inflammatory response prompted by FasL expression, which contributes to neutrophil recruitment and interleukin‐1 beta (IL‐1β) release, seems to be crucial to chronic liver damage, persistence of viral infections, and probably initiation and / or promotion of HCC. In order to evaluate the expression of Fas, FasL, and IL‐1β in different stages of human liver disease and to determine whether hepatitis B virus (HBV) and hepatitis C virus (HCV) infections modulate their expression, also in relation to apoptosis, we examined 87 liver samples obtained from patients with: chronic hepatitis (CH) (n.42), cirrhosis (n.9) and hepatocellular carcinoma (HCC) (n.16) and corresponding peritumoural tissues (n.16); histologically‐normal liver (n.4) as controls. Fas, FasL and IL‐1β mRNA were quantified using reverse transcriptase‐polymerase chain reaction. The apoptotic index was evaluated by TUNEL analysis. Our data showed a progressive Fas / FasL increase from CH to cirrhosis followed by a decline from the latter to HCC. In histological sections apoptosis was detected in HCC. A significant difference emerged between HCV and HBV‐related disease for IL‐1β expression only in CH. A significant positive correlation between IL‐1β and FasL in HCV‐related disease (P = 0.014) and an inverse correlation between IL‐1β and Fas in HBV‐related disease (P = 0.021) were observed. The different pattern of IL‐1β, Fas and FasL expression found in HCV‐ and HBV‐mediated liver disease, points to a different modulation of immune response B and C virus induced, while the decline in Fas / FasL expression in HCC may be related to defence mechanisms adopted by HCC cells against the immune system.
Absence of spirochaetes (Borrelia burgdorferi) and piroplasms (Babesia microti) in deer ticks (Ixodes dammini) parasitized by chalcid wasps (Hunterellus hookeri)
Authors: MATHER THOMAS N. , PIESMAN JOSEPH , SPIELMAN ANDREW
Published: March 2008

ABSTRACT. An entomophagous wasp (Hunterellus hookeri Howard) parasitizes about a third of the host‐seeking nymphal Ixodes dammini Spielman et al. ticks on Naushon Island in Massachusetts (U.S.A.) where the agents of Lyme disease (Borrelia burgdorferi Johnson et al.) and human babesiosis (Babesia microti Franca) are enzootic. Following blood‐feeding, wasp‐parasitized ticks are destroyed by the developing wasp. The prevalence of either human pathogen in host‐seeking ticks collected in wasp‐infested sites is nearly 40% lower than that found in other sites. Nymphal ticks, collected early in their season of activity, are more frequently parasitized by the wasp and less frequently by the Lyme disease spirochaete than those collected later in the summer. Spirochaetes never infected wasp‐infected ticks, and few wasp‐infected ticks were concurrently infected by the Babesia piroplasm. Taken together, these correlations indicate that the wasp may render the tick inhospitable to both pathogens. The presence of the wasp may have reduced risk of human infection on the island by either pathogen by as much as a third.
Climatological correlates of screwworm (Cochliomyia hominivorax) abundance in Texas, U.S.A.
Authors: KRAFSUR E. S.
Published: March 2008

ABSTRACT. The causes of screwworm (Cochliomyia hominivorax) outbreaks in North America are not well understood, but the literature suggests that climate was historically important. Screwworm case incidence in each of seven climatological divisions of Texas was examined for the years 1962‐83, the period when sterile‐male releases were made. Weak but statistically significant correlations were found between winter and summer cases and mean winter and summer rainfall and temperature when the independent variables were examined one at a time. Multiple regression of log case incidence on previous quarterly cases and current rainfall and temperatures showed a significant, negative effect of temperature on summer cases. Lagged screwworm cases accounted for most of the variation in quarterly cases. No climatic effects were detected in the other seasons. Rainfall was statistically unrelated to screwworm abundance in any season even in an arid region. The analysis does not support a climatic genesis of screwworm outbreaks or eradication. The sterile‐male method is a credible explanation for screwworm disappearance.
Two populations of Phlebotomus ariasi in the Cévennes focus of leishmaniasis in the south of France revealed by analysis of cuticular hydrocarbons
Authors: KAMHAWI SHADEN , MOLYNEUX D. H. , KILLICK‐KENDRICK R. , MILLIGAN P. J. M. , PHILLIPS ANGELA , WILKES T. J. , KILLICK‐KENDRICK MIREILLE
Published: March 2008

ABSTRACT. Two distinct populations of Phlebotomus ariasi Tonnoir have been identified in the Cevennes focus of leishmaniasis in the south of France using gas‐liquid chromatography (GLC) of cuticular hydrocarbons extracted from individual dried female flies. Results were obtained after analysis of flies collected from CDC light traps from a domestic and a sylvatic site separated by a distance of 900 m. Flies were provided for GLC analysis as six blind samples. Using cluster and discriminant analysis techniques, five of the samples were shown to form two distinct groups, while a sixth was identified as a mixture.

These findings were subsequently confirmed to correspond exactly with the way the samples had been presented. Samples grouped together on the basis of the flies' cuticular hydrocarbon profiles had been taken from the same site, while the ungrouped sample had been deliberately mixed.

Using a jack‐knifed estimator, it is shown that specimens can be correctly allocated to the population to which they belong with a 92% success rate.

These results confirm the value of the technique for the identification of populations of medical vectors. The implication of the findings for the epidemiology of leishmaniasis is discussed with special reference to the need to determine if both populations are vectors and to study differences in behaviour.

In addition to adults, profiles of larval sandflies have been obtained for the first time.
Diel rhythms of tick parasitism on incubating African penguins
Authors: DUFFY DAVID CAMERON , DATURI AUGUSTA
Published: March 2008

ABSTRACT. 1. Ticks (Ornithodoros capensis Neumann) were most abundant on incubating host African penguins (Spheniscus demersus Linnaeus) at 24.00 hours and least abundant during 09.00–12.00 hours during 4 day periods in May and October at 3 h intervals.

2. Ticks were three times as abundant in May, the start of the breeding season, as in October, at its end.

3. Air temperature and humidity appear less important than light levels in determining tick activity.

4. The degree of tick parasitism of breeding seabirds is best studied at night.
Management of insecticide resistance in control of the Simulium damnosum complex by the Onchocerciasis Control Programme, West Africa: potential use of negative correlation between organophosphate resistance and pyrethroid susceptibility
Authors: KURTAK DAN , MEYER ROLF , OCRAN MICHAEL , OUÉDRAOGO MOUSSA , RENAUD PIERRE , SAWADOGO R. O. , TELE BARRO
Published: March 2008

Abstract. 1. Resistance of some populations of the Simulium damnosum complex to temephos (100‐fold at the LC50 level), with degrees of cross‐resistance to chlorphoxim (14‐fold) and other organophosphate insecticides, follows intensive larvicidal control of S.damnosum s.l. in West African river systems since 1975 by the WHO Onchocerciasis Control Programme.

2. Larvae of at least three sibling species of the S.damnosum complex have become organophosphate‐resistant: these are the forest species S.sanctipauli Vajime & Dunbar and the savanna species S.sirbanum V. & D. and S. damnosum Theobald sensu stricto.

3. Organophosphate‐resistant S.damnosum s.l. larvae show increased susceptibility to some organochlorine and pyrethroid insecticides, especially to permethrin (up to 11‐fold) and OMS 3002 (up to 17‐fold), as compared with organophosphate‐susceptible populations.

4. This differential susceptibility is reflected by increased pyrethroid efficacy in operational use for river treatments against organophosphate‐resistant field populations of S.damnosum s.l. larvae. Treatment of 100 km of the lower Bandama River in 1985 showed that permethrin at the highly selective dosage of 10 min exposure to 0.01 mg/1 caused reversion towards organophosphate‐susceptibility of the target population of S.sanctipauli. This effect was less pronounced when the Comoe River was treated at the lower dosage of 0.005 mg/1 for 10 min.

5. To overcome temephos‐resistance, it is proposed that the most rational usage of currently available larvicides would involve the following annual sequence of treatments: Bacillus thuringiensis serotype H‐14 when river discharge is below 75 m3/s; chlorphoxim for about eight weekly treatment cycles after river discharge rises; permethrin (or alternative pyrethroid) for up to six treatment cycles ‐ this should eliminate any incipient selection for chlorphoxim‐resistance; resume chlorphoxim (or perhaps carbosulfan) treatments until river discharge falls below 75 m3/s permitting resumed use of B.t. H‐14.
Efficacy of Bacillus sphaericus 2362 against larvae of Anopheles gambiae under laboratory and field conditions in West Africa
Authors: NICOLAS L. , DARRIET F. , HOUGARD J. M.
Published: March 2008

Abstract. A flowable concentrate of Bacillus sphaericus (Neide) strain 2362 was applied against Anopheles gambiae Giles s.l. mosquito larve in small plot field trials in Bobo‐Dioulasso area, Burkina‐Faso. Third and fourth instar larvae were controlled for 10–15 days with a dosage of 10 g/m2, 3–10 days with 1 or 0.1 mg/m2, and 2 days with 0.01 g/m2.

Complete elimination of larval populations required lx102 to 2times103 viable spores/ml in the larval feeding zone.

After treatment, the total numbers of viable spores decreased in the ponds, due to ingestion of spores by non‐target as well as target organisms and/or to loss of viability of some spores by sunlight. This formulation was less effective against An.gambiaehan against Culex quinquefasciatus Say larvae, both in laboratory bioassays and under field conditions.
Mites from house dust in Glasgow
Authors: COLLOFF M. J.
Published: March 2008

Abstract. Glasgow's mild, high‐rainfall climate, combined with a deteriorating quality of housing and low standards of living in many parts of the city, makes it a particularly suitable place for thriving populations of house dust mites. The acarofauna in 124 samples of house dust from beds and carpets in seventy‐four homes in Glasgow, Scotland, comprised thirty‐one species of which the most abundant were Dermatophagoid.es pteronyssinus (Trouessart) (64.3%), Glycyphagus domesticus (De Geer) (16.7%), Euroglyphus maynei (Cooreman) (11.6%), Tarsonemus sp. (1.6%), Cheyletus eruditus (Schrank) (1.5%), C.trouessarti Oudemans (0.9%), Tarsonemus fusarii Cooreman (0.8%) and Glycyphagus destructor (Schrank) (0.7%). Mites were present in all the homes surveyed and the mean population density was found to be 97/100 mg of dust (range 2–1210). Over 47% of homes visited showed signs of disrepair associated with damp, especially unmodernized flats in old tenement buildings and 1960s council housing stock, many of which contain deprived occupants. There was a high incidence of hygrophilic species such as Glycyphagus spp., Tarsonemus spp. and Euroglyphus maynei in such homes. Samples from homes of atopic asthmatics were found to contain significantly fewer mites than those from normal volunteers (x2=54.7). This was partly due to the use of house dust mite avoidance measures (e.g. regular vacuum cleaning of mattresses as well as carpets) by some of the asthmatics.
Development of resistance in rabbits to immature stages of the Ixodid tick Rhipicephalus appendiculatus
Authors: RECHAV Y. , DAUTH J.
Published: March 2008

Abstract. A study of acquired resistance in rabbits to larvae and nymphs of Rhipicephalus appendiculatus Neumann showed a positive correlation between the levels of γ globulin in the serum and the resistance developed by the host. A negative correlation between the weight of engorged ticks and γ globulin levels was also demonstrated during this study. Repeated infestations with ticks evoked a typical antibody response to antigenic challenge. The levels of γ globulin stabilized after three infestations and no further decrease in the weight of ticks was observed. The mechanism of the acquisition of resistance by the rabbits, the production of antibodies and the involvement of complement are discussed.
Efficacy of permethrin‐impregnated curtains for malaria vector control
Authors: MAJORI G. , SABATINELLI G. , COLUZZI M.
Published: March 2008

Abstract. Preliminary results obtained by the use of permethrin‐impregnated curtains against the Afrotropical malaria vectors Anopheles gambiae Giles s.l. and An.funestus Giles are reported and discussed. Field trials were carried out in villages near Ouagadougou, Burkina Faso. Houses were provided with curtains made from 100% cotton netting, impregnated with permethrin at the dose of lg a.i./m2, to cover the doorway, the window(s) and the space under the eaves. Entomological data collected during the period 1985‐86 showed residual permethrin activity for about a year, and almost complete prevention of indoor‐resting mosquitoes. Increased exit‐rate and mortality‐rate of house‐entering malaria vectors were also obtained. Utilization of this malaria vector control method in primary health care programmes is advocated.
Development of a system for sterilizing tsetse flies, Glossina spp., in the Held
Authors: HALL M. J. R. , LANGLEY P. A.
Published: March 2008

Abstract. Various autosterilizing systems were evaluated on natural populations of Glossina pallidipes Austen and G.morsitans morsitans Westwood in Zimbabwe. These involved a clear plastic tower of two or three chambers mounted at the cage position on a trap. Inside one chamber flies could be exposed to the vapour phase of the chemosterilant bisazir, P,P‐bis (l‐aziridinyl)‐N‐methylphosphinothioic amide. The system was designed to encourage flies to enter the sterilizing chamber, delaying their exit for sufficient time to expose them to a sterilizing dose. This was accomplished in the most effective system by restriction of the exit to one small hole (6 mm diameter) at the roof‐side junction. The number of flies remaining in the chamber declined exponentially. The rate of exit was directly proportional to the density of flies in the sterilizing chamber and to the number of exit holes. The probability of a fly being in this chamber for at least 1 or 7 min (the times taken for female and male G.m.morsitans respectively to receive an ED50) was 0.84 and 0.67 respectively with one fly present. With sixteen flies, these probabilities were 0.76 and 0.18 respectively. Results suggest that it may be possible to develop a cheap, safe and efficient autosterilizer for use on tsetse traps.
Trypsin and chymotrypsin‐Iike enzymes of the sandfly Phlebotomus papatasi infected with Leishmania and their possible role in vector competence
Authors: BOROVSKY D. , SCHLEIN Y.
Published: March 2008

Abstract. Phlebotomus papatasi (Scopoli) is susceptible to infection with Leishmania major Yakimov & Schokov and resistant to L.donovani Laveran & Mesnil. The possibility that susceptibility depends on midgut levels of trypsin and chymotrypsin‐like (esterolytic) enzymes was investigated. Infection with L. major reduced the trypsin‐like activity to 93.5% and 86% of the control value at 20 and 30 h post feeding and increased it to 106% at 52 h. Infection with L.donovani reduced trypsin‐like activity to 64% and 73% of the control value at 30 and 52 h post feeding. The overall amount of trypsin and chymotrypsin‐like enzymes in L.major infections was reduced to 50% and 34% of the control value at 20 and 30 h post feeding and increased to 184% at 52 h. Only one of the enzymes separated by gel electrophoresis was lower throughout, i.e. peak D. Overall, the midgut enzyme level with L. donovani infection was 86% of the control value at 30 h post feeding and 105% at 52 h; their relative amounts changed throughout. Soybean trypsin inhibitor enabled L.donovani to survive and multiply in P.papatasi. It is suggested that a specific component of the trypsin‐like activity prevents the survival of L.donovani in P.papatasi and that modulation of this factor enables L.major to survive.
Septic tank mosquitoes: competition between species in central Nigeria
Authors: IRVING‐BELL R. J. , OKOLI E. I. , DIYELONG D. Y. , LYIMO E. O. , ONYIA O. C.
Published: March 2008

Abstract. Exit traps, placed over the air vents of septic tanks, were used to examine species diversity and relative abundance of mosquitoes breeding in ammonia‐rich waters of septic tanks. Of the six species found, Culex deceits Theobald and Culex cinereus Theobald appeared to be competing successfully with Culex quinquefasciatus Say during the wet season but not during the long dry season. The seasonal timing of their displacement by Cx quinquefasciatus was variable and did not correlate well with climatic factors. The three other species present, generally during the wet season and early dry season, were Culex tigripes G. & C, Culex horridus Edwards and Aedes aegypti (L.).

Experimental bucket ovitraps were used to assess preference towards covered (dark) septic tank water in comparison with sunlit septic tank water, covered and sunlit compost water. These were colonized by Cx quinquefasciatus, Cx decens, Ae.aegypti and Ae.vittatus Bigot. The covered septic tank water was more abundantly colonized by Cx quinquefasciatus and marginally so by the two Aedes species. Cx decens appeared to colonize the exposed compost water more readily in the dry season, but changed to the covered septic tank water in the wet season.

The discussion centres around competition between these mosquito species and concludes that it would be useful to know what environmental factors, or what aspects of competition, lead to severe natural reductions in the abundance of the major pest species Cx quinquefasciatus.
Evaluation of some adhesives for collecting Musca domestica and Chrysomya megacephala adults or mosquito larvae in sticky traps
Authors: SULAIMAN SALLEHUDIN , YUNUS HASHIM , SOHADI RAHIM
Published: March 2008

Abstract. 1. Seven types of water‐insoluble adhesives were evaluated in sticky traps for collecting adults of Musca domestica L. and Chrysomya megacephala (Fabricius) or mosquito larvae (Aed.es aegypti (L.) and Culex quinquefasciatus Say).

2. Adhesive viscosity affected the tackiness of the glues and this determined their trapping efficiency in air or water.

3. From the ‘Hyvis’ range of adhesives tested, ‘Hyvis 200’ was most effective for trapping adult flies.

4. With 24 h exposure to fourth instar Ae.aegypti larvae in tapwater, submerged plates coated with ‘Hyvis 10’, ‘Hyvis 30’ or ‘Hyvis 200’ formulations trapped the majority of larvae. In polluted water the highest rates of trapping were 17.3% of Ae. aegypti and 18.7% of Cx quinquefasciatus with ‘Hyvis 200’. Floating traps were consistently less productive than submerged traps under laboratory conditions.

5. In a heavily polluted natural breeding‐site of Cx quinquefasciatus, floating traps were more productive than submerged sticky traps with four of seven adhesives tested, the most efficient being ‘Hyvis 200’ (4.2 mosquitoes per hour) and Hyvis:polyethylene 90:10 (4.5/h). Despite the relative inefficiency of aquatic traps, emergent adults, pupae and second to fourth instars of larvae were collected quickly from the habitat.
A behavioural bioassay to identify attractive odours for Glossinidae
Authors: SAINI R. K. , DRANSFIELD R. D.
Published: March 2008

Abstract. 1. A behavioural bioassay, based on antennal movement responses, was developed using Glossina morsitans morsitans Westwood for screening chemical attractancy to tsetse.

2. Chemicals found to be attractive to male tsetse were acetone, formaldehyde, methylethylketone, methylvinylketone, l‐octen‐3‐olandpen‐tanal but not acetophenone, hexanal, lactic acid or urea.

3. Female tsetse responded to all these chemicals, more strongly than males for the first six attractants, less strongly than males for the other four chemicals.

4. These laboratory bioassay findings agree with field observations on tsetse responses to certain chemical odours. Therefore this behavioural bioassay should be a useful laboratory test procedure for screening attractants.
Fecundity and size in the housefly: investigations of some environmental sources and genetic correlates of variation
Authors: IV W. C. BLACK , KRAFSUR E. S.
Published: March 2008

Abstract. Environmental sources and genetic correlates of variation in fecundity and size were studied in field and laboratory housefly populations in central Iowa, U.S.A. Electrophoresis of enzymatic proteins was used to monitor genotypes and heterozygosity. In the field, mean fecundity declined as adult densities increased. Fecundity varied greatly within breeding seasons. Fly body size varied spatially and temporally during summer and winter. Fecundity and size were positively correlated. Size was independent of genotypes at the six loci studied. No relationship was observed between heterozygosity and the magnitude or variability of body size.
The life expectancy of phlebotomine sandflies: first field estimates from southern France
Authors: DYE C. , GUY M. W. , ELKINS D. B. , WILKES T. J. , KILLICK‐KENDRTCK R.
Published: March 2008

Abstract. 1. A field study of Phlebotomus ariasi Tonnoir, the vector of Leishmania infantum Nicolle in southern France, addressed the following questions: Is it possible to estimate reliably the life expectancy of this sandfly; can spatial or temporal variation in the life expectancy be detected, and is such variation significant for disease transmission?

2. Life expectancy was estimated by examining follicular relics in the ovaries of more than ten thousand females caught in light traps at seven sites in the Cévennes and the Garrigues, throughout their active period in 1985 and 1986. Whilst the distinction between nulliparous and parous flies was easily made, assessments of the number of times a parous fly had laid eggs were unreliable. Best estimates of life expectancy were therefore calculated from the parous rate.

3. Large samples collected from one site in the Cevennes in both years gave very similar estimates of life expectancy.

4. There was also no significant difference between estimates obtained from the Cévennes and the Garrigues, despite their distinct vegetation and climates. Therefore, large regional differences in sandfly population size and the prevalence of canine leishmaniasis cannot be explained by a difference in adult survival rate.

5. With no systematic annual or regional variation, a useful mean life expectancy can be calculated from the data collected at all sites in both years. It is 1.54 (SE 0.04) ovarian cycles. However, this estimate is sensitive to the assumption that survival rate is a discrete rather than a continuous variable.

6. Local variation in the parous rate may be associated with the proximity of traps to P.ariasi emergence sites.
Honeydew sugars in wild‐caught Phlebotomus ariasi detected by high performance liquid chromatography (HPLC) and gas chromatography (GC)
Authors: MOORE J. S. , KELLY T. B. , KILLICK‐KENDRICK R. , KILLICK‐KENDRICK M. , WALLBANKS K. R. , MOLYNEUX D. H.
Published: March 2008

Abstract. Phlebotomus ariasi Tonnoir sandflies were caught in light traps hung in oak trees and in a house in the Cévennes focus of leishmaniasis in the South of France. The flies were cryopreserved either immediately on removal from the traps, or after starvation for 6–7 days, or after 6–7 days starvation followed by exposure to oak infested with the aphid genera Lachnus or Thelaxes.

After transportation to the laboratory, the sandflies were thawed and aqueous extracts of the crushed flies were analysed for their carbohydrate content using high performance liquid chromatography (HPLC) and gas chromatography (GC).

Starved female sandflies lacked significant amounts of any saccharides. Four types of sugar, melezitose and its hydrolysis products turanose, glucose and fructose, were observed in flies which had been starved previously and then placed with Lachnus infested oak. The results also indicate the presence of hydrolysis products of melezitose: (a) in flies previously starved and placed with Thelaxes infested oak, (b) in P.ariasi cryopreserved direct from the light traps hung in oak trees infested with Lachnus and Thelaxes, and (c) flies caught in a house. Unidentifiably small quantities of a trisaccharide were also detected in the latter groups of flies. In previous tests, sugars were detected in P.ariasi after their exposure to aphid‐infested oak (Quercus ilex L.), but not when P.ariasi females were exposed to washed oak leaves without aphids.

The results indicate that P.ariasi feed on melezitose and/or turanose, the main local source of which is aphid honeydew. A better understanding of sugar meal sources of sandflies using HPLC and GC techniques will assist in our understanding of sandfly/Leishmania relationships, parasite transmission and epidemiology.
The phlebotomine sandflies of Venezuelan Amazonia
Authors: FELICIANGELI M. DORA , PEREZ JAIME RAMIREZ , RAMIREZ ALIRIO
Published: March 2008

Abstract. Phlebotomine sandflies were surveyed in two ecologically contrasted areas, the northern moist and southern wet tropical forests, of the Territorio Federal Amazonas, Venezuela.

Three new taxa and twenty‐one new records were added to the previously known species list for Venezuelan sandflies, which now totals eighty species. Both sexes of Lutzomyia (Psychodopygus) killickisp.n., L.(Trichophoryomyia) bettiniisp.n., L.(Nyssomyia) olmeca reductasubsp.n. and and the females of L.bernalei Osorno et al., Brumptomyia pintoi Costa Lima and L.begonae (Ortiz & Torres) are described and illustrated.
Morphology and identification ofChrysopslarvae from Nigeria
Authors: INAOKA TOHRU , HORI EITARO , YAMAGUCHI KATSUYUKI , WATANABE MAMORU , YONEYAMA YOHTARO , OGUNBA EUGENE O.
Published: March 2008

Abstract.Mature larvae of four Afrotropical species ofChrysops(Diptera: Tabanidae):C.centurionisAusten,C.distinctipennisAusten,C.longicornisMacquart andC.silaceusAusten, are decribed and illustrated from specimens collected in Nigeria, identified by rearing associated adult flies. The descriptions pay special attention to the value of ultrastructural characters, such as cuticular striations, observed by scanning electron microscopy (SEM).
Population relationships of Simulium yahense and Simulium sanctipauli in the Firestone Rubber Plantation at Harbel, Liberia
Authors: FRYAUFF DAVID J. , TRPIS MILAN
Published: March 2008

Abstract Comparative genetic differences for the phosphoglucomutase and trehalase loci were surveyed in larval and adult blackfly populations of the onchocerciasis vectors Simulium yahense Vajime and Dunbar, and S.sanctipauli Vajime and Dunbar. Genotype frequencies for each stage and all populations were at Hardy‐Weinberg equilibrium, indicating that S.yahense and S.sanctipauli remain genetically distinct. S.yahense populations from three different locations were found to be genotypically comparable. The larval population of S.yahense found in closest proximity to a S. sanctipauli population was found to express the phosphoglucomutase allele 1.33, characteristic of S.sanctipauli, with significantly greater frequency than other larval populations of S.yahense. This may constitute evidence of limited genetic introgression of S.sanctipauli with the S.yahense population.
Use of fluorescent pigments for the automatic marking of tsetse flies in traps
Authors: HALL MARTIN J. R.
Published: March 2008

Abstract. A means of contaminating tsetse flies in the field with fluorescent pigment powders has been developed, using pigment in open‐ended plastic chambers at the cage position on traps. Glossina pallidipes Austen and G.morsitans morsitans Westwood passed rapidly through the chambers, and on exit were contaminated with consistent doses of powder: about 90 μg/fly when powder was presented on the chamber roof and about 28 μg/fly when powder was presented on the chamber floor. The technique automatically marks tsetse flies with pigment, cheaply, simply and with the minimum imposition of stress and is expected to be particularly useful in ecological studies. Its potential for marking other biting flies is discussed.
Diel activity patterns of blood‐seeking anthropophilic mosquitoes in central Sweden
Authors: JAENSON THOMAS G. T.
Published: March 2008

Abstract. 1. Blood‐seeking diel activity cycles of mosquitoes are described from 24 h landing catches on human bait in a field and a forest habitat during June‐August in central Sweden.

2. Daytime activity in the field was low or absent, whilst in the forest activity was relatively even throughout the diel.

3. In both habitats, activity peaks generally occurred about sunset and sunrise and were more distinct in the field than in the forest.

4. Data from this and other studies show that, in general, Aedes cinereus Meigen feeds at night in field‐type habitats and Ae.communis (DeGeer) during the diurnal‐crepuscular period in forest and woodland habitats.

5. Although abundant in the study area, Anopheles maculipennis Meigen sensu lato, Culex pipiens L., Cx torrentium Martini and Culiseta morsitans (Theobald) were not caught on the human bait. This is because, in central Sweden, An.maculipennis s.l. is mainly feeding in animal sheds whereas the others are ornithophagous.

6. Ae.geniculates (Olivier) was recorded from central Sweden for the first time.

7. Blood feeding success (proportion of mosquitoes that managed to obtain blood from the human bait) was significantly greater in Ae.cinereus (14.9%) than in Ae.punctor (Kirby), Ae.communis and Ae.annulipes (Meigen) (2.8–0.7%).

8. The data are interpreted in relation to the transmission of Ockelbo disease (caused by Sindbis virus) and tularaemia in Sweden.
Landing periodicity of the mosquito Aedes aegypti in Trinidad in relation to the timing of insecticidal space‐spraying
Authors: CHADEE DAVE D.
Published: March 2008

Abstract. Diel landing periodicity (biting cycle) of domestic Aedes aegypti (L.) in Trinidad, West Indies, was monitored using human bait during January‐August 1980. The periodicity of females was predominantly diurnal (95.2% arriving during daylight or twilight) and bimodal, with consistent peaks at 06.00–07.00 and 17.00–18.00 hours. The diel periodicities at indoor and outdoor sites were virtually identical. Larger numbers of adults were collected outside than inside houses. It is recommended that the time of insecticidal ULV adulticiding should coincide with peaks in landing periodicity of the Ae.aegypti adults.
Maggot therapy: a review of the therapeutic applications of fly larvae in human medicine, especially for treating osteomyelitis
Authors: SHERMAN RONALD A. , PECHTER EDWARD A.
Published: March 2008

ABSTRACT. In traditional medical practice, the larvae of some Diptera: Calliphoridae, notably Lucilia illustris (Meigen), L. sericata (Meigen) and Phormia regina (Meigen), have been employed for maggot therapy, i.e. to help clean lesions antiseptically, especially for treatment of chronic osteomyelitis. This mode of treatment remains appropriate for cases where antibiotics are ineffective and surgery impracticable.
The functional response of Toxorhynchites rutilus rutilus to changes in the population density of its prey Aedes aegypti
Authors: HUBBARD STEPHEN F. , O'MALLEY SEAN L. C. , RUSSO RAYMOND
Published: March 2008

ABSTRACT. We present an analysis of the functional response of the predator Toxorhynchites rutilus rutilus (Coquillett) to changes in the density of the larvae of Aedes aegypti (L.) (Diptera: Culicidae). The experiment was replicated for five different ages, and at three different densities of the predator. The data were fitted to Rogers' (1972) random predator equation by non‐linear least‐squares in order to estimate searching efficiency and handling time for each experimental treatment. The data show that estimated searching efficiencies are highest at intermediate ages of the predator for all predator densities tested. Handling time declines exponentially with increasing predator age. There is a marked interference effect; searching efficiency decreases with increased predator density, and this is most pronounced at intermediate prey ages. Estimated handling times increase with predator density at a rate which declines with increasing predator age.
A field study of mating between two species of bedbug in northern KwaZulu, South Africa
Authors: WALPOLE DEBRA E. , NEWBERRY K.
Published: March 2008

ABSTRACT. The interspecific cross‐mating of female Cimex lectularius Linnaeus with male Cimex hemipterus (Fabricius) results in a visible mark developing in the female ectospermalege. This mark has been used to record the frequency of mating between female C. lectularius and male C. hemipterus in sympatric wild populations in a DDT‐sprayed area of northern KwaZulu, South Africa. A high percentage (11/16=69%) of C. lectularius females were marked, showing that these two species mate in nature.
Observations on the susceptibility of Ctenocephalides felis (Siphonaptera: Pulicidae) to malathion and permethrin in Tanzania
Authors: KILONZO B. S. , GISAKANYI N. D.
Published: March 2008

ABSTRACT. Laboratory‐reared Ctenocephalides felis (Bouche) adults were tested with 0.5% malathion and 0.5% permethrin, using the standard WHO methods. After 24 h exposure to malathion (3.6 mg/cm2), 92% of the fleas died. The LT50 for malathion was approximately 8 h. Permethrin (0.45 mg/cm2) produced 100% mortality of exposed insects after 24 h while with a higher dose (0.9 mg/cm2) all fleas died after 8 h exposure. LT50 for the two doses of permethrin were 7.7 and 1.05 h, respectively.

The failure of the diagnostic dose of malathion to kill 100% of the population was attributed to resistance. Permethrin is a suitable pesticide for controlling fleas of domestic animals in Tanzania.
Detection and localization of antibody ingested with a mosquito bloodmeal
Authors: HATFIELD P. R.
Published: March 2008

ABSTRACT. Mouse immunoglobulins were found to persist in Aedes aegypti (L.) mosquito bloodmeals for 2–3 days after ingestion. Immunoenzyme labelling revealed mouse antibody specifically bound to the mosquito midgut epithelium after ingestion; immunogold labelling of thin sections revealed mouse antibody within the cytoplasm of the microvilli on the midgut epithelium. Ingested mouse antibody was not conclusively demonstrated bound to tissues outside the gut, though antibody was detected in mosquito haemolymph using a sensitive ELISA test. Possible mechanisms by which antibody may cross mosquito gut barriers and actions that in vivo antibody: antigen reactions may have on these blood‐fed insects are discussed.
Leishmaniasis in the Jordan Valley. V. Dispersal characteristics of the sandfly Phlebotomus papatasi
Authors: YUVAL BOAZ , WARBURG ALON , SCHLEIN YOSEF
Published: March 2008

ABSTRACT. Several characteristics of dispersing and non‐dispersing Phlebotomus papatasi (Scopoli) were quantified and compared. The majority of dispersing sandflies, trapped crossing fallow fields, were females (68.5% v. 51.1%); of the dispersing females, 55.4% were parous, 48.1% were inseminated and 11.6% were gravid. In the population of sandflies sampled exiting from burrows of the sand rat Psammomys obesus Cretschmar, these categories, respectively, represented 39%, 90% and 26% of the females examined. Leishmania promastigotes were found in 9% of females exiting from P. obesus burrows, and in 2.7% of the dispersing females. The anthrone test established that the reason for activity of gravid females is sugar feeding. These females do not disperse and are suitable targets for future control measures.
Activities and physiological states of male and femaleTabanus sackeni
Authors: TAYLOR PHILIP D. , SMITH STEPHEN M.
Published: March 2008

ABSTRACT.Male and femaleTabanus sackeniFairchild (Diptera: Tab‐anidae) were collected on a road, dipping at pools of water on a road, and at uv‐light traps; females were also caught in Malaise traps. Most males at uv‐light traps were collected just before sunrise. Most females at uv‐light traps were collected in the evening and most had recently taken a blood‐meal. Malaise‐trapped females showed a distinct crepuscular peak of host‐seeking activity. Crop volumes were variable in these host‐seeking females; many had large crops. Crop volumes were small in individuals of both sexes collected dipping or on the road. Many dipping females were gravid. By examining how physiological states and the behaviour of individuals changed according to trap type, we are able to make inferences about the timing and importance of a number of unobserved activities. A link between uptake of water and sugar feeding was apparent and we postulate that mating takes place in the early morning, just before sunrise.
Permethrin‐impregnated bednets: behavioural and killing effects on mosquitoes
Authors: HOSSAIN M. I. , CURTIS C. F.
Published: March 2008

ABSTRACT. Permethrin‐treated pieces of netting and simulated bednets were evaluated against Anopheles gambiae Giles and Aedes aegypti (L.) in the laboratory. When female mosquitoes were allowed to feed on a human arm through pieces of impregnated netting fastened at the end of tubes, doses above 2 g/m2 were required to stop blood‐feeding of both An. gambiae and Ae. aegypti. A much lower dose prevented Ae. aegypti from feeding on mice through impregnated netting. When mosquitoes were released in a room and a human subject sat under a permethrin‐impregnated (0.2 g/m2) bednet with an arm pressed against the net (mesh 1.5 mm), mosquitoes failed to bite through the net. All the mosquitoes trying to bite through or entering the net through holes cut in it were knocked down within 30 min of release and ultimately died. Permethrin‐impregnated wide‐mesh (4 or 8 mm) bednets similarly prevented entry and caused high mortality‐rates of An. gambiae.
The effects on domestic infestations of Cimex lectularius bedbugs of interspecific mating with C. hemipterus
Authors: NEWBERRY K.
Published: March 2008

ABSTRACT. Interspecific mating between male Cimex hemipterus and female C. lectularius bedbugs (Hemiptera: Cimicidae) occurs freely in the laboratory, even when many female C. hemipterus are available. Longevity and fertile egg production of female C. lectularius are reduced by mating with male C. hemipterus. In KwaZulu, South Africa, a correlation exists between the percentage of C. lectularius females which are interspecifically mated and the predominance of C. hemipterus in mixed domestic infestations of these bedbugs. When C. hemipterus constitutes over 75% of the infestation, the majority of C. lectularius females lay only sterile eggs.
Expression of acquired immunity to immature stages of the tick Rhipicephalus evertsi evertsi by rabbits and guinea‐pigs
Authors: CLARKE FRANCOISE C. , ELS D. A. , HELLER‐HAUPT A. , RECHAV Y. , VARMA M. G. R.
Published: March 2008

ABSTRACT. Acquired immunity in guinea‐pigs and rabbits to immature stages of the two‐host tick Rhipicephalus evertsi evertsi Neumann was demonstrated. Repeated infestations of both hosts with larvae resulted in a significant reduction in the weight of later engorged nymphs. A sharp decline in the numbers of nymphs which successfully fed on both hosts was also observed. This study provides evidence for a gradual decrease in the mean weight of engorged nymphs towards the end of the detachment period suggesting that, in two‐host ticks, the onset of nymphal feeding acts as an immune booster in a host already primed by the larval feed and that this results in a reduced feeding performance.
Rate of trypanosome killing by lectins in midguts of different species and strains of Glossina
Authors: WELBURN SUSAN C. , MAUDLIN I. , ELLIS D. S.
Published: March 2008

ABSTRACT. The activity of lectins in different species of tsetse was compared in vivo by the time taken to remove all trypanosomes from the midgut following an infective feed and in vitro by agglutination tests. Teneral male Glossina pallidipes Austen, G.austeni Newstead and G.p.palpalis R‐D. removed 50% of all Trypanosoma brucei rhodesiense Stephens & Fantham infections within 60 h. A ‘refractory’ line of G.m.morsitans Westwood took 170 h to kill 50% infections while a ‘susceptible’ line of the same species failed to kill 50%. Agglutination tests with midgut homogenates showed differences between fly stocks which accorded with differences in rate of trypanosome killing in vivo.

Flies fed before an infective feed were able to remove trypanosomes from their midguts more quickly than flies infected as tenerals. Increasing the period of starvation before infection increased the susceptibility to trypanosome infection of non‐teneral flies. Teneral flies showed little agglutinating activity in vitro, suggesting that lectin is produced in response to the bloodmeal.

Feeding flies before infection also abolished the differences in rate of trypanosome killing found between teneral ‘susceptible’ and ‘refractory’G.m.morsitans, suggesting that maternally inherited susceptibility to trypanosome infection is a phenomenon limited to teneral flies.

Electron micrographs of midguts of G.m.morsitans suggest that pro‐cyclic trypanosomes are killed by cell lysis, presumably the result of membrane damage caused by lectin action.
Size and mortality rates of Glossina pallidipes in the semi‐arid zone of southwestern Kenya
Authors: DRANSFIELD R. D. , BRIGHTWELL R. , KIILU J. , CHAUDHURY M. F. , ABIE D. A. AD
Published: March 2008

ABSTRACT. Seasonal changes in the mean size of tsetse, Glossina pallidipes Austen, as indicated by wing vein length, were monitored during 1983‐86 at Nguruman, southwestern Kenya. Changes in size of nulliparous females and wing fray category 1 males were shown to be correlated with the relative humidity 2 months before they were captured. Soil temperature when flies were in the pupal stage had much less effect. Size dependent mortality was demonstrated, with the mean size of flies emerging from pupae significantly less than that of field‐caught flies. This mortality must occur at emergence, since there was no evidence of size‐dependent mortality once the flies became available to the trap. Size was correlated with density‐independent mortality acting on the parent population 2 months previously. It might therefore be possible to use size as an index of the intensity of such mortality. This could be useful when assessing the level of additional mortality required to suppress tsetse populations.
Lectin signalling of maturation of T.congolense infections in tsetse
Authors: WELBURN SUSAN C. , MAUDLIN I.
Published: March 2008

ABSTRACT. The process of maturation of Trypanosoma congolense Broden in tsetse has been shown to be initiated by lectin secreted in the fly midgut. In the present study the duration of lectin signal required to induce maturation was determined by the sequential addition or removal of a specific lectin inhibitor (D+glucosamine) to the diet of infected male Glossina morsitans Westwood. An established midgut infection of T.congolense was found to require, at most, 72 h exposure to midgut lectin to begin the process of maturation. Longer exposure to midgut lectin increased the frequency of maturation, suggesting clonal variation in response to lectin stimulation occurs within trypanosome stocks. It is suggested that this variation corresponds to differences in lectin binding sites on the trypanosome surface. Midgut trypanosomes retained their ability to mature throughout their life in the fly; when lectin activity in the midgut was inhibited, the trypanosomes remained as procyclic forms but when this inhibition was removed maturation was able to proceed. This indicates that the process of maturation is dependent upon a signal from the fly and is not predetermined by the trypanosomes undergoing a fixed number of division cycles. The possible role of lectins in the maturation of trypanosomes in vitro is discussed.
Vector capacity of Rhipicephalus appendiculatus and Amblyomma variegatum for Thogoto and Dhori viruses
Authors: JONES LINDA D. , DAVIES CLIVE R. , STEEL GORDON M. , NUTTALL PATRICIA A.
Published: March 2008

ABSTRACT. Experimental studies were undertaken to ascertain the vector potential of Rhipicephalus appendiculatus Neumann and Amblyomma variegatum Fabricius for Thogoto (THO) and Dhori (DHO) viruses, candidate members of the Orthomyxoviridae. In the first set of experiments, ticks were infected orally by feeding on viraemic hamsters. THO virus replicated in R.appendiculatus and A.variegatum, persisted trans‐stadially in both tick species, and was transmitted to susceptible hosts during feeding. In contrast, both R. appendiculatus and A. variegatum were refractory to per os infection by DHO virus. In the second set of experiments, engorged R. appendiculatus and A. variegatum nymphs were parenterally inoculated with DHO virus. The virus persisted transstadially in both tick species and was transmitted by bite to susceptible hosts. These results indicate that the midgut acts as a barrier to per os infection of R.appendiculatus and A. variegatum by DHO virus. However, when this barrier is bypassed, i.e. by parenteral inoculation, both R.appendiculatus and A.variegatum can serve as efficient vectors of DHO virus.
Phlebotomine vectors of the leishmaniases: a review
Authors: KILLICK‐KENDRICK R.
Published: March 2008

ABSTRACT. An account is given of work published during the past 10 years incriminating species of phlebotomine sandflies as vectors of Leishmania species which infect man.

An assessment is made of the degrees of certainty of the vectorial roles of eighty‐one species and subspecies of sandflies (thirty‐seven Old World and forty‐four New World) in the transmission of twenty‐nine leishmanial parasites of mammals. At least one species of sandfly is considered to be a proven vector of each of ten parasites.

Of the eighty‐one sandfly taxa, evidence is judged to be sufficient to incriminate nineteen as proven vectors (eleven Phlebotomus species and eight Lutzomyia species or subspecies) and evidence for a further fourteen (nine Phlebotomus species and five Lutzomyia species or subspecies) is considered to be strong.

The suggested criteria for incrimination of a vector are anthropophily and common infection with the same leishmanial parasite as that found in man in the same place. More weight should be given to natural infections persisting after the digestion of a bloodmeal than those in the presence of blood. Supporting evidence is a concordance in the distribution of the fly and the disease in man, proof that the fly feeds regularly on the reservoir host, a flourishing development of the parasite in infected flies and the experimental transmission of the parasite by the bite of the fly.
Population‐genetic evidence for two species in Anopheles minimus in Thailand
Authors: GREEN CHRISTOPHER A. , GASS RETO F. , MUNSTERMANN LEONARD E. , BAIMAI VISUT
Published: March 2008

ABSTRACT. Sympatric occurrence of homozygotes for two electro‐morphs controlled by a locus for octanol dehydrogenase, and the absence of heterozygotes, at two localities, indicates two isomorphic species within the taxon Anopheles minimus Theobald in Thailand. This view is supported by significant, relative deficiences of heterozygotes at other electromorphic loci. Gene frequency data are reported for seven electro‐morphic loci in An.minimus sensu lato from eleven localities: one of the newly recognized species predominated in all but one locality and the second was confined to two localities. This species pair of An.minimus s.l. was clearly distinguished from An.aconitus Donitz, An.pampanai Biittiker & Beales and An.varuna Iyengar, three species closely related to An.minimus s.l. in the series Myzomyia of Anopheles subgenus Cellia.