摘要:

Abstract.We have applied the recently developed Random Amplified Polymorphic DNA (RAPD) method to produce species‐specific, DNA profiles for two sympatric, Venezuelan sandfly species, thought to be the vectors responsible for recent outbreaks of cutaneous and mucocutaneous leishmaniasis in the Andean State of Tachira. Moreover, within the profile, it was possible to identify a diagnostic DNA band forLu.youngiof 0.32 kb. Results showed that the size of this diagnostic DNA band remained constant and did not vary with sex or geographical distributio

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00677.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Human specific genetic markers have been used to profile the human DNA found within a mosquito bloodmeal. In this technique, variable numbers of tandem repeat (VNTR) sequences are employed to prime amplification of human DNA in the polymerase chain reaction (PCR) and the radiolabeled products are analysed by high resolution denaturing gel electrophoresis. Matching of DNA profiles allows identification of the individual human host.Bloodmeals of 125 femaleAnopheles gambiaeGiles mosquitoes, caught dead or alive in verandah‐trap huts wherein two people had slept overnight protected by intact insecticide‐impregnated bednets, were analysed: thirty‐five out of thirty‐nine profiles generated were identical to those of the sleepers under the nets. Thus the blood‐fed mosquitoes found after impregnated nets have been used cannot, in most cases, be explained away by entry of already fed mosquitoes into

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00678.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Recently the sandflyPhlebotomus guggisbergiwas found to be a vector ofLeishmania tropicacausing cutaneous leishmaniasis in the Laikipia focus, Kenya, but extensive searches have shed no light on the identity of the rural reservoir host(s). In order to discover more about the biology of the vector, a host feeding preference study was conducted on wild sandflies in their natural cave environment over a 6‐month period. Solid state Army miniature (SSAM) traps, without light bulb, were suspended over cages with potential hosts or an empty cage control. The animals tested included sheep, goat, dog, cat, hamster, rabbit, giant rat(Cricetomys gambianus), crested rat(Lophiomys imhausi)and rock hyrax(Procavia capensis), all of which (except hamsters) are normally found in the vicinity of the study site. Sandfly collections from traps baited with goat, sheep, cat, dog, rabbit, or wild rodent species were significantly higher than the control, whereas trap collections with hamster and rock hyrax were not significantly different from the control. Numbers of sandflies collected from the goat, sheep and cat were significantly greater than from the rabbit and rodents. The sex ratio also varied between collections: larger animals attracted a higher proportion of femaleP.guggisbergithan did the smaller animals (P>0.05). Therefore greater emphasis should be placed on surveying larger animals to assess their status as reservoir hosts forL.tropicain Keny

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00679.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Extracts of rabbit food, hay and rabbit faeces elicited a positive oviposition response from gravid femaleLutzomyia longipalpissandflies (Diptera: Phlebotominae). Combined extract of rabbit food and oviposition pheromone had a synergistic effect on sandfly egg‐laying, greatly increasing the number of eggs laid and resulting in a highly targeted response. Individually tubed flies, exposed to the combined extract, were shown to be 3.5 times more likely to survive oviposition and laid 2.5 times more eggs than control flies. A laboratory oviposition trap baited with the combined extract was tested in a cage and caught 31 (62%) of 50 gravidL.longipalpisover a 72h perio

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00680.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Bloodmeal digestion in midguts of the sandfliesPhlebotomus papatasiandPhlebotomus langeroni(Diptera: Psychodidae) was investigated in optimized assays to detect general protease, trypsin and aminopeptidase activities using synthetic substrates. Optimal activity occurred at pH 8‐9 for all enzymes examined in both species. Protease activity peaked at 24‐34h post human bloodmeal in midguts ofP.papatasiand 34‐48h inP'.langeroni;all endo‐ and exoprotease activities were completed by 50 h inP.papatasicompared to 72 h inP. langeroni.Hydrolysis of two chymotrypsin substrates was<2% of trypsin activity in both species. Aminopeptidase activity was associated mainly with the midgut wall, whereas trypsin activity was confined to the midgut lumen. A feature of digestion inP.langeroniwas the high level of aminopeptidase recorded within 10h of the bl

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00681.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Sera from 41 horses and 159 donkeys, from twelve States of México, were tested to ascertainanti‐Gasterophiluscirculating antibodies by double immunodiffusion (DD), counterimmunoelectrophoresis (CIE), indirect haemagglutination (IH), thin layer immunoassay (TIA) and diffusion‐in‐gel ELISA (DIG‐ELISA) methods using crude somatic antigen from third instar larvae ofG.intestinalis(DeGeer). At necropsy, 33/41 horses and 24/159 donkeys were found to be parasitized byG.intestinalisand/orG.nasalis(L.).Gasterophilus intestinaliswas the species most commonly found in the equines. Analysis of the sera from the infested animals by DD showed positive results of 21.2% in horses and of 8% in donkeys. Screening the sera with CIE gave sensitivities of 69.7% in horses and of 32% in donkeys. Examination of the sera by IH showed positive results of 87.9% and of 48% in horses and donkeys, respectively. Testing the sera with TIA gave sensitivities of 93.9% in horses and of 96% in donkeys. Analysis of horses' sera by DIG‐ELISA showed a sensitivit

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00682.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.In mud‐and‐thatch houses of Santiago del Estero Province, northwest Argentina, where no insecticides had been sprayed officially to control domestic infestations of the Chagas disease vectorTriatoma infestans(Klug) (Hemiptera: Reduviidae), two knockdown (KD) insecticidal collection procedures were compared with the standard flush‐out (FO) method for samplingT. infestans.Bugs were collected by FO using 0.2% tetramethrin in bedrooms of (1) 41 houses of Amama village employing 1 man‐hour of capture effort per house, and (2) 19 houses of Trinidad and Mercedes villages employing 4 man‐hours/house. From the same houses, 2‐5 days after the manual FO collection, bugs were collected by KD indoor‐spraying of deltamethrin 25mga.i./m2in Amama, or burning of one γ‐HCH (=γ‐BHC) fumigant tablet 3.1g of γ‐isomer) per bedroom in Trinidad and Mercedes. The majority of infestations were detected by both methods, the proportion of positive houses being 81% at Amama and 95% at the other villages. Although the FO method was more sensitive, at least because it was applied first, the KD method detected infestations in 25% of houses where bugs were not found by FO. Bug densities estimated by FO or by subsequent KD in each house were significantly correlated:r =0.795 for deltamethrin;r= 0.882 for y‐HCH. Compared with FO collections ofT.infestanslarge stages, i.e. adults plus fourth and fifth instar nymphs, the KD catch averaged 0.88x with deltamethrin and 0.57× with γ‐HCH, regardless of the apparent population density of bugs per house. However, the KD method has practical advantages

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00683.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Recent predictive models for the distribution of the African tickRhipicephalus appendiculatusNeumann, based on the computer packages CLIMEX and BIOCLIM and data derived from meteorological satellites, and for the seasonal dynamics of the same tick using the computer simulation models ECFXPERT and T3HOST, all have their limitations. Statistical analysis of the relationships between the seasonal abundance of all three life stages of this tick and climatic and satellite‐derived data from five sites in southern Africa, taken from the literature, supports a new perspective that it is the timing of the questing activity of the desiccation‐vulnerable larvae that determines the pattern of the tick's seasonal dynamics. The timing of the activity of nymphs and adults is determined by temperature‐dependent development rates plus the delaying phenomenon of photoperiod‐sensitive diapause, the timing and duration of which have evolved to achieve maximum generation survival by ensuring the occurrence of eggs and larvae during periods of optimal climatic conditions. The most important environmental factor appears to be night‐time minimum temperature, determining condensation and saturation deficit and thus the tick's ability to replenish moisture lost during the daytime and so to survive while questing for hosts. It is the larvae whose numbers are correlated most closely with these factors, consistent with earlier experimental results showing larvae to be most susceptible to desiccating conditions. There is a statistical linkage between larval tick numbers and satellite imagery, arising from the correlation between larval numbers and minimum temperature and saturation deficit conditions, and in turn the relationship between these climatic conditions and the subsequent vegetational changes monitored by the satellites. Moisture availability to larvae is likely to be the critical factor throughout the geographical range ofR.appendiculatus, but the precise combination of climatic conditions that optimize moisture availability and questing tick survival can be expected to vary geographically. The relationships between ticks, temperatures and satellite data in parts of equatorial Africa have yet to be established. These correlative patterns highlight both the critical life stage and environmental factors when trying to understand temporal, and ultimately spatial, variations in tick

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00684.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.This paper reports the results of a laboratory study showing effectiveness of a new insect repellent N,N‐diethylphenylacetamide (DEPA) against stable fly,Stomoxys calcitrans, and compared to N,N‐diethyl‐m‐toluamide (DEET) and dimethyl‐phthalate (DMP). DEPA gave maximum protection time of more than 6h at 3% concentration followed by DEE

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00685.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract.Descriptions are given of the morphological features of laboratory‐reared first to third larval stages ofCochliomyia hominivorax.The pseudo‐cephalon, spines and papillae of the segments, and the anterior and posterior spiracles of all three larval stages were studied by scanning electron microscope micros

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1993.tb00686.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY