摘要:

Abstract.To evaluate the vector competence of someLutzomyiaspp. (Diptera: Psychodidae) forLeishmania (Viannia)spp. (Kinetoplastida: Trypanosoma‐tidae), experimental infections of anthropophilic sandflies from the Colombian Pacific coast were performed, through membrane feeding and xenodiagnosis on hamsters infected withLe.(V.)braziliensisorLe.(V.)panamensis.Wild‐caught or F, generation females ofLutzomyia gomezi, Lu.hartmanni, Lu.panamensisandLu. trapidoiwere allowed to feed on hamster lesions and then maintained at 26oC and>80% r.h. on a sugar‐water diet until dissection on the fifth day post‐infection (p.i.).Despite similar infection rates (range 37–44%) in bothLu.gomeziandLu.trapidoi, infections were heavier (>100 parasites) in the latter species. Infections ofLu.trapidoiwithLe.braziliensis(n= 21) andLe.panamensis (n= 27) showed parasite migration toward the foregut, with promastigote colonization of the stomodeal valve and appearance of infective forms. In contrast, infections ofLu.gomeziwithLe. braziliensis (n= 10) andLe.panamensis (n =5) were light (<50 parasites) and usually restricted to the pylorus. InLu.hartmanni, only a few promastigotes were found in the pylorus and midgut of 3/8 specimens infected withLe.braziliensis, and noLe.panamensisdeveloped(n =19). By day 5 p.i., promastigote colonization of the hind‐ and midgut byLe.panamensiswas observed in 2/4Lu.panamensisbut notLe.braziliensis (n= 3).It was concluded thatLu.trapidoiis a more efficient vector thanLu.gomezifor bothLe.braziliensisandLe.panamensis, and thatLu.hartmanniandLu.panamensisare of minor importance forLeishmaniatransmission in this e

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00375.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Anopheles gambiaemidgut extracts and haemolymph possessed agglutinins, titre 1:16 to 1:256, against human red blood cells (RBCs). Subjection of both tissues to protein precipitation reagents, organic chemical and selected protease, neuraminidase and other glycosidic hydrolase treatments revealed the haemagglutinins to be protein, most likely glycoprotein, in nature ‐ not lipoprotein, lipid, glycolipid or nucleic acid.An.gambiaeagglutinins were thermo‐labile>40oC, affected by freezing and thawing treatments, and contained disulphide and hydrogen bonds on the basis of sensitivity following exposure to dithio‐threitol and urea respectively. Optimum haemagglutination depended generally on slightly acid to neutral pH conditions and agglutinin activity was Ca2+ion, albeit to a lesser extent Mg2+ion, dependent. The midgut extract agglutinin subunit molecule had a relative molecular weight (Mr) of 65kDa whilst that of haemolymph was 40kDa.This study presents the first report on selected physico‐chemical properties, the glycoproteinaceous nature and tentative subunit Mrof mosquito midgut extract and haemolymph anti‐RBC aggl

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00376.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.In 1991, as part of an epidemiological study of bluetongue viruses (BTV) in the Central American and Caribbean region, eight farms located in Costa Rica, Honduras, Panama and Puerto Rico were sampled forCulicoidesspp. attacking cattle. Using cattle bait, 3884 biting midges were collected with an electric aspirator during both crepuscular periods. The predominant species captured wasCulicoides insignisLutz (95%), followed byC.furens(Poey) (3.4%),C.filariferHoffman/C.ocumarensisOrtiz (0.9%),C.lahillei(Iches) (0.7%),C.arubaeFox and Hoffman (<0.1%) andC.gorgasiWirth and Blanton (<0.1%). Blood‐engorged specimens from some of these species were collected and comprised: 18% of allC.insignis, 36% ofC.furens, 37% offilarifer/ocumarensisand 25% ofC.lahillei.No engorgedC.arubaeorC.gorgasiwere caught. These results confirm earlier findings pointing toC.insignis, C.furensandC.filarifer/ ocumarensisas potential vectors of BTV in the regio

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00377.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.An indirect enzyme‐linked immunosorbent assay (ELISA) has been developed to identify the bloodmeal sources ofCulicoides impunctatusGoetghebuer. Nightly light trapping in Scotland, between April and September 1992, caught a total of 344 blood‐engorged femaleC. impunctatus, all in May, June and July. The insects were stored in 70% ethanol and tested 5–7 months later. Bloodmeal sources were positively identified for 246 (71.5%). Bovine hosts were most common (38.4%), followed by deer (23.0%) and sheep (9.9%). Only one midge had fed on human blood. Relatively freshly fed (<24h), fully engorged females gave the clearest results. The wider applications of the technique to the study ofCulicoideshost preferences is disc

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00378.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.The semiochemicals carbon dioxide (CO2) and l‐octen‐3‐ol (octenol) were evaluated as attractants at several release rates, alone and in combination, for the major coastal species of biting midges in Georgia:Culicoides furens, C.hollensisandC.melleus(Diptera: Ceratopogonidae). The data show that CO2is an effective attractant for the females of all three species, but each has a different response pattern. In contrast, octenol was an effective attractant only forC.furens, either alone or in combination with CO2; octenol had a repellent effect on the other two species. The combination of octenol and C02had a synergistic effect on the collections ofC.f

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00379.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Under controlled laboratory conditions of 28–30oC and 16:8 L:D photoperiod, an attempt was made to develop an age‐grading technique forAnopheles culicifaciesmales. Mating activity was maximal when females were 5–12 days old and males were 5–7 days old. The numbers of total and mature spermatocysts declined significantly with age, and the proportion of the testes occupied by the sperm reservoir increased as virgin males grew older. Mating resulted in the loss of spermatozoa and accessory gland substance from the reproductive system. Loss of mating ability of older virgin males seemed to be age‐related, because the reproductive system contained ample supplies of accessory gland substance and spermatozoa. Morphological changes of the reproductive system, due to mating and age, were used to infer the age and reproductive history of unknown males in a laboratory e

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00380.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Gas chromatography (GC) analysis of 159 specimens (144 females and 15 males) ofLutzomyia youngicollected in Shannon traps in a coffee plantation in the Andean region of western Venezuela, where leishmaniasis is endemic, revealed the presence of fructose, sucrose, glucose and maltose in the gut and crop of the wild sandflies.The identification of the sugars was confirmed by comparing retention times with those observed for standard sugars and those obtained from sandflies experimentally fed on known sugar solutions.Although the sandflies in nature may ingest each of the four sugars, the results suggest that it is more probable there is an invertase enzyme (glycosidase?) in the gut or crop of the sandfly which hydrolyses ingested disaccharides (e.g. sucrose) to the constituent monosaccharides (i.e. fructose and glucose).Ecological and altitudinal distributions of sandfly species may be related to the availability of specific sugar sources, with epidemiological implications. Identification of the preferred sugar could make breeding easier and would facilitate further research onLeishmania–wectorrelationship

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00381.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.The ability of adultStomoxys calcitrans(L.) (Diptera: Muscidae) to retain viableEhrlichia risticii(Rickettsiaceae), the aetiologic agent of Potomac horse fever (PHF), and mechanically transmit the pathogen from citrated bovine blood artificially infected withE.risticiito susceptible mice was studied. ViableE. risticiiwere found in the digestive tract ofS.calcitrans3h after the flies had engorged to repletion on infected blood; however, noE. risticiiwere detected in flies ≥2 days after feeding. Subsequently, groups ofS.calcitranswere fed for 20 s on infected blood, then fed to repletion on mice 30, 60,130, 180 or 220 min after having feeding interrupted. Mice displayed no clinical signs of PHF and did not produce anti‐E. risticiiantibodies when assayed 30 days afterS. calcitranshad fed. AlthoughS.calcitranswere able to harbour viableE.risticiifor at least 3h, transmission of the disease agent to susceptible mice during interrupted feeding was not demonstrated under these experimental conditi

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00382.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Abstract.Midgut protease activity inGlossina morsitans centralisandG. m. morsitans, at 48h post bloodmeal averaged 1.8IU of trypsin‐like activity. These two tsetse subspecies differ in their susceptibility to trypanosome infection. Except for low levels in flies fed on waterbuck blood (0.7IU), activity did not differ in flies fed a variety of host bloods (goat, pig, cow, buffalo, eland) and trypanosome species (Trypanosoma congolense, T.brucei, T.simiae). Protease activity was also not correlated with infection rates, despite large differences in infection rates among experiments. Nevertheless, addition of 0.06M D(+)‐glucosamine to parasitaemic blood resulted in a three‐fold reduction in protease activity, coincident with a large increase in infection rate. This effect did not occur when parasites or D(+)‐glucosamine were added alone to the bloodmeal, suggesting that the effect was due to metabolism of D(+)‐glucosamine by

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00383.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

ISSN:0269-283X    

DOI:10.1111/j.1365-2915.1994.tb00384.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY