摘要:

Abstract.The malaria transmission potential of wild, infectiveAnophelesfrom western Kenya was evaluated by determining the number of sporozoites transmittedin vitroby salivation when their mouthparts were inserted into capillary tubes containing either sucrose or blood. With sucrose, 86.6% of 102 infectiveAnophelestransmitted a geometric mean (GM) of 3.84 sporozoites (range 1–34). With blood, 23.1% of 104 infectiveAnopheles, tested on the day of collection, transmitted a GM of 2.30 sporozoites (range 1–117). ForAnophelesheld 5 days postcapture before testing with blood, 53.6% of 56 transmitted a GM of 6.04 sporozoites (range 1–420). TransmittingAnophelescontained significantly more salivary gland sporozoites than non‐transmitters. No significant differences were detected betweenAnopheles gambiaeGilessensu latoandAnopheles funestusGiles in sporozoite transmission by individuals with sporozoites in their salivary glands.Sporozoites were detected microscopically in the salivary duct from heads in 80.3% of 117 infectiveAnopheles(GM=11.2, range 1–71). Sporozoite detection in mosquito heads by ELISA was 25% less efficient than microscopic detection.Over 98% of the infectiveAnophelestransmitted less than twenty‐five sporozoites. Transmitted sporozoites represented only about 3% of the total sporozoites in the salivary glands suggesting that sporozoite transmission may be restricted to sporozoites in the salivary duct at the time of feeding. Results are discussed in relation to anti‐sporozoite vaccin

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00523.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The head, thorax, wings, legs and abdomen of 320 wild‐caughtAnopheles gambiaeGilessensu latoand 115An.funestusGiles were tested by an enzyme‐linked immunosorbent assay (ELISA) forPlasmodium falciparumWelch to determine how anatomical dissemination of circumsporozoite (CS) protein could affect the estimation of malaria sporozoite rates by ELISA. Of fifty‐threeAnopheleswith CS protein detected in any body part, positive reactions were observed for 58.5% of heads, 67.0% of thoraces, 39.6% of wings, 52.8% of legs and 60.4% of abdomens. Mean absorbance values (range 0–2.00) were highest in thorax samples (1.17), followed by heads (0.80), abdomens (0.67), wings (0.48) and legs (0.46).Circumsporozoite protein was present in the wings or legs, but not in the head or thorax, in 11.3% (6/53) of the infectedAnopheles.The ELISA infection rate of 12.8% (41/320) forAn.gambiaewould have increased to 14.7% (47/320) by inclusion of six mosquitoes with CS protein in wings or legs alone. The slight overestimation of the proportion of infective mosquitoes due to disseminated CS protein would have little effect on estimates of relative infection rates by ELISA for field‐collectedAnopheles, with abdomens removed prior to testing. However, the widespread dissemination of CS protein indicates that sporozoite load estimates by ELISA, for mosquitoes without abdomens, may not provide adequate measurements of the numbers of sporozoites in the salivary glands. Operationally, careful processing of mosquito samples for the determination of infectively rates by ELISA is necessary to prevent the mixing of wings or legs among samples representing individual m

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00524.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.Response of femaleLutzomyia longipalpisLutz&Neiva (Diptera: Psychodidae) to an oviposition attractant and/or stimulant associated with conspecific eggs was investigated in the laboratory. Females of two populations laid significantly higher mean number of eggs on sites with 160 eggs already present than on bare control sites. This response was lost when eggs placed on test sites were previously washed in organic solvents and distilled water. Age of eggs placed on test sites, 1–6 days after being laid, did not seem to affect the oviposition response of the females. Comparing effects of different numbers of eggs, positive responses were obtained when 80, 160 or 320 eggs were placed on test sites. No significant differences between mean egg numbers laid on test sites and controls were detected when batches of only 20 or 40 eggs were use

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00525.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.An Insect Activity Monitor was created to measure the behavioural responses of fleas (Siphonaptera). The apparatus allows for a range of visual, chemo‐ and mechanoreceptor cues to be presented. The jumping response is detected by counting amplified pulses produced as the fleas land on a stretched membrane held over a microphone. Horizontal movements are detected using a system of infra‐red beams and phototransistors which, when broken, are counted as a measure of activity.The apparatus was tested usingCeratophyllus hirundinis(Curtis),Ceratophyllusfarreni(Rothschild) andCeratophyllus rusticus(Wagner), co‐inhabiting species from the nests of the house martin(Delichon u.urbicaL.). No unaided emigration or immigration has been demonstrated in these species (Clark, 1988) and much of their time is spent confined to the darkness of the nest. In addition to species contrasts, females were more active than males and fleas were more active at 25oC than at 18oC.The more active bird fleaCeratophyllus garei(Rothschild) from the nest of pheasant(Phasianus colchicusL), was tested for responses to light of varying intensity. Activity was stimulated by white light, but not proportional to light inte

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00526.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The role of the louseTrinoton anserinum(F) as an intermediate host ofSarconema eurycerca(Wehr) was investigated in swans. 8.3% of healthy swans carried one to twelve lice per bird, dispersed contagiously. Injured and lead‐poisoned swans were more heavily infected.The mouthparts appear designed to penetrate the hosts' skin; the mandibles are robust and asymmetric, and the maxillae have a serrated intercutting surface. 22% fed exclusively on blood and 33% on both blood and feather. All life‐cycle stages fed upon blood and the barbs and barbules from down feathers; hooklets from contour feathers were only found in adults. 9% of lice were infected with developing nematode larvae in the head, thorax or abdomen.Lice labelled with Technetium 99 m moved towards the scapulas and the wings. Lice were found to be highly active and were mob

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00527.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.1he significance ofGlossina fuscagroup tsetse flies as vectors of cattle trypanosomiasis was examined using biconical traps to survey tsetse populations at one site in Gabon and two sites in Zaire.2Mean trypanosome infection rates inG.tabaniformisWestwood over the study period ranged from a minimum of 8.9% at one site to a maximum of 17.7% at another. The mean infection rate inG.nashiPotts was 6.0%.3Up to 49% of bloodmeals ofG.tabaniformiswere from cattle. Trypanosome prevalence in cattle whereG.tabaniformisappeared to be the main vector was 9.5% and 5.4% at the Mushie and OGAPROV ranches, respectively.4A highly significant positive correlation was found between tsetse challenge and trypanosome prevalence in N'Dama cattle across sites. Tsetse challenge was defined as the product of tsetse relative densities, trypanosome infection rates in the flies and the proportion of feeds taken by them from cattle. Thus,G.tabaniformiscan be an important vector of pathogenicTrypanosomaspecies in cattle.

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00528.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

Abstract.The pyrethroid insecticide lambda‐cyhalothrin was evaluated in field trials againstGlossina f.fuscipesand sleeping sickness transmission in Iyolwa sub‐county, Tororo District, Uganda. The insecticide was applied selectively to the resting‐sites of tsetse, by bush‐spraying, using 10% wettable powder (10WP) formulation at an application rate of 11.6 g a.i./ha over an area of 28 km2, or by a 2% Electrodyn formulation (2ED) applied at 0.9 g a.i./ha over 30 km2. In a third trial area of 32 km2, 215 pyramidal traps treated with lambda‐cyhalothrin 100 mg/m2were set.The best impact was obtained with 10WP lambda‐cyhalothrin which eliminated tsetse within 1–2 months, whereasG.f.fuscipespersisted at very low density in part of the area treated with 2ED lambda‐cyhalothrin. In both treated areas the numbers of human sleeping sickness cases fell to no more than one per month, compared with four to twelve per month previously. The overall rate of cattle trypanosomiasis(T.bruceiandT.vivax)was also reduced slightly. Insecticide‐treated traps remained fully effective for at least 6 months under field conditions and catches were reduced 20–90‐fold. These results in the control of tsetse and trypanosomiasis transmission lead us to recommend lambda‐cyhalothrin for ts

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00529.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00530.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00531.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1991.tb00532.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY