bluuebunny/crossref_metadata_2025 huggingface dataset:
Oral susceptibility of Aedes albopictus to dengue type 2 virus: a study of infection kinetics, using the polymerase chain reaction for viral detection
Authors: TARDIEUX ISABELLE , POUPEL OLIVIER , RODHAIN FRANCOIS , LAPCHIN LAURENT
Published: March 2008

Female Aedes albopictus mosquitoes, aged 1 week, were infected with DEN‐2 dengue virus. The kinetics of infection in mosquito brain and mesenteron were monitored using DNA probes with polymerase chain reaction (PCR) amplification of target DNA sequences coding for DEN‐2 virus envelope protein, compared with the standard immunofluorescence assay technique (IFA).

Rates of virus detection in the mesenteron of orally infected mosquitoes rose to 38% by day 4 post‐inoculation, then declined until day 8, followed by irregular peaks around days 11–14 and subsequently. In mosquito head squashes, virus was detected from day 4 onwards, reaching 38% positive by day 18. Salivary glands of all the same females were found to be positive for virus by day 8 onwards. Parenterally infected Ae.albopictus females were all positive for DEN‐2 in the brain and salivary glands 8 days post‐inoculation. In every case, results obtained with the PCR matched those from the IFA. Our DNA probe with PCR procedure can therefore be utilized as a sensitive and reliable method for studies of DEN‐2 vectors.
Evaluation of neem, Azadirachta indica, with and without water management, for the control of culicine mosquito larvae in rice‐fields
Authors: RAO D. R. , REUBEN R. , VENUGOPAL M. S. , NAGASAMPAGI B. A. , SCHMUTTERER H.
Published: March 2008

Applications of neem, Azadirachta indica (Meliaceae), to rice‐fields were evaluated with the dual objective of controlling the culicine mosquito vectors of Japanese encephalitis virus (JEV) and enhancing the grain yield. Since crude neem products deteriorate under improper storage conditions, a laboratory bioassay was developed to screen neem cake powder against mosquito larvae, Cule.x quinquefasciatus. Only samples of neem giving over 90% bioassay mortality were used in field trials.

When good quality neem cake powder was applied at the dose of 500 kg/ha, either alone or coated over urea, there was a striking reduction in the abundance of late instar culicine larvae and pupae. Only fourteen pupae were obtained over a period of 13 weeks in neem cake powder treated plots, and four in those treated with neem coated urea, compared with 101 in control plots. Both treatments were significantly less than the control, but on par with one another.

In another field trial, neem cake coated urea was tested at 500 and 250kg neem/ha in combination with water management practices. No reduction in efficacy was noted at the lower dose. Larval abundance in plots under water management alone did not differ significantly from the controls, but was significantly reduced when water management was combined with neem products. Two stable formulations, ‘Neemrich‐I’ (lipid rich) and ‘Neemrich‐H’ (azadirachtin rich), also gave good suppression of immature culicines.

All the treatments with neem also gave higher grain yield than the control. Therefore, it is feasible to develop an acceptable package for community use, particularly as the Agricultural Department already recommends the use of both water management and neem cake coated urea to farmers.
Biting and resting behaviour of anophelines in western Venezuela and implications for control of malaria transmission
Authors: RUBIO‐PALIS YASMIN , CURTIS C. F.
Published: March 2008

A study was conducted in three villages in western Venezuela between February 1988 and October 1989 to determine the biting and resting activity of anophelines in relation to human habits, rainfall and fenitrothion spraying of houses. Mosquitoes were collected landing on humans inside and outside experimental huts throughout the night. Only three mosquitoes were found resting in the huts in the morning, but 2470 were collected resting on vegetation in the early morning. The collections yielded eleven species of anopheline, the most abundant being Anopheles nuneztovari, comprising over 75% of the total anophelines collected, followed by An.triannulatus, An.albitarsis s.l. and An.oswaldoi.

The four most abundant species showed different diel patterns of biting. For An.nuneztovari the peak of activity was close to midnight indoors and outdoors, for An.triannulatus between 19.00 and 20.00 hours outdoors, for An.albitarsis mainly before midnight indoors and outdoors and for An.oswaldoi outdoors at 19.00 hours, with an additional smaller peak indoors at midnight. Most of the human population use bednets, go to bed before 22.00 hours and are therefore most exposed to mosquitoes that bite outdoors early in the night.

Fenitrothion house‐spraying failed to prevent large mosquito populations developing in the wet season, presumably because of their exophilic resting habits. The possible advantages of impregnation of existing bednets with pyrethroids, and provision of nets for people who do not have them, are discussed.
Population genetic confirmation of species status of the malaria vectors Anopheles willmori and An.pseudowillmori in Thailand and chromosome phylogeny of the Maculatus group of mosquitoes
Authors: GREEN C. A. , RATTANARITHIKUL RAMPA , CHAROENSUB ATI
Published: March 2008

Among the Anopheles (Cellia) maculatus group of Oriental mosquitoes, positive assortative mating occurs within sympatric and synchronous populations of An.willmori and An.pseudowillmori in the presence of populations of An.maculatus and An.sawadwongporni, judged from the occurrence of inversion homozygotes and the absence of any heterozygotes in their distinctive, polytene chromosomes. Genotypic frequencies for enzyme electromorphs give additional evidence for the species status of An.pseudowillmori and a practical means of identification in field studies of malaria vectors.

Autosomal rearrangements are referred to those of An.stephensi which is unique for 4y. An. willmori differs by a single inversion, 4x; An.pseudowillmori by three Arm 2 inversions; and An.dispar by one Arm 2 inversion and 4x.

Fixed autosomal rearrangements in the Maculatus group are summarized and their phylogenetic distribution suggests some unknown, intrinsic mechanism by which genome structure is disrupted in association with speciation events. This could be relevant to the potential genetic manipulation of malaria vectors.
Activation of three species of tsetse (Glossina spp.) in response to host derived stimuli
Authors: WARNES M. L.
Published: March 2008

Recordings were made of the activation of hungry Glossina morsitans morsitans Westwood, G.pallidipes Austen, and G.austeni Newstead in response to odours from ox breath and ox urine, and a moving visual stimulus, in a wind tunnel. The spontaneous activity of G.m.morsitans was very low (less than 4% of males and 2% of females active per min during control periods). That of G.austeni and G.pallidipes was in the region of 20% except for G.pallidipes females when in excess of 40% were active during control periods. Addition of ox urine odours to the airstream had no effect on activity in any of the species investigated but addition of ox breath odours to the airstream significantly increased activity of G.pallidipes and of G.m.morsitans, although for the latter only approximately 12% of flies were active. For G.austeni the addition of ox breath odours resulted in a significant increase in activity of females but not of males. The moving visual stimulus resulted in a significant increase in the activity of both sexes of G.austeni and G.m.morsitans but no change in the activity of G.pallidipes. The low level of spontaneous activity and the low response to ox breath odours in a strain of G.m.morsitans maintained in the laboratory since 1969 was compared with a new colony of this species which originated from puparia collected in Zimbabwe in 1991. No differences in either spontaneous activity or the response to ox breath odour was recorded, but females from the new colony were significantly more responsive to a moving visual stimulus. In a further series of experiments the activity of G.m. morsitans and G.pallidipes was recorded at varying wind speeds. For both species, activity decreased as the wind speed increased. The results are discussed in terms of the likely host‐location strategies used by these species.
Distribution of breeding and control of the filariasis vector Aedes samoanus in leaf axils of Pandanus in Samoa
Authors: SAMARAWICKREMA W. A. , SONE FOLA , SELF L. S. , CUMMINGS R. F. , PAULSON G. S.
Published: March 2008

Water in leaf axils of the screwpine Pandanus was sampled for mosquito immature stages at seventy villages in Upolu, fifty‐five in Savai'i and three in Manono, the main islands of Samoa. Ten plants in every patch of Pandanus plantation were sampled at each village. Among 23,049 mosquito larvae collected from Upolu, 77% were the filariasis vector Aedes (Finlaya) samoanus, 17.7% were Ae.(Fin.)oceanicus and 5.3% were Ae.(Fin.)tutuilae. Out of 6981 larvae taken in Savai'i, 23.2% were Ae.samoanus, 67.6%Ae.oceanicus and 9.2%Ae.tutuilae. When larval counts per plant were analysed for each district, Ae.samoanus was found to predominate in Pandanus in Upolu and Ae.oceanicus in Savai'i. However, the adult density of Ae.samoanus was higher in Savai'i and this was attributed to the large areas of forests with Freycinetia for Ae.samoanus breeding. In Pandanus in Savai'i the number of Ae.samoanus was negligible. In Upolu, with more urbanization and larger plantations, there was greater breeding of Ae.samoanus in Pandanus. Two control trials were conducted against Ae.samoanus larvae in Pandanus, one using a sand culture of the parasitic nematode Romanomermis culicivorax and the other with temephos, an organophosphate insecticide. While R.culicivorax did not adapt to the leaf axil habitat, all plants were without larvae for 5 weeks after treatment with temephos.
Chigger mites of the genus Leptotrombidium: key to species and their distribution in China
Authors: DUN‐QING WANG , ZI‐ZHONG YU
Published: March 2008

. Chigger mites of the genus Leptotrombidium (Acari: Trombieulidae) transmit scrub typhus, caused by Rickettsia tsutsugamushi (=R.orientalis) in South‐East Asia. In China, eighty‐two species of Leptotrombidium have been recorded; these are listed with the names of Provinces where they were found. Five species, L.deliense, L.insularae, L.kaohuense, L.rubellum and L.scutellare, have been implicated as Chinese vectors of scrub typhus. A brief key is given to the larvae of all but three of the Leptotrombidium mites known in China.
Changes in enzyme titres with age in four geographical strains of Aedes aegypti and their association with insecticide resistance
Authors: MOURYA DEVENDRA T. , HEMINGWAY JANET , LEAKE COLIN J.
Published: March 2008

Abstract. The enzymes acetylcholinesterase, glutathione S‐transferase (GST), glucose 6‐phosphate dehydrogenase (G6PD), and general esterases were assayed in four strains of Aedes aegypti mosquitoes aged between 1 and 30 days. Microtitre plate methods were used to assay activity in the homogenates of individual mosquitoes. The levels of GST and G6PD declined with the age of the mosquitoes, while the activity for the other enzymes remained constant. Soluble protein content was also found to decline with mosquito age in all the strains.

Insecticide bioassays showed that two strains (Trinidad and Virtudes) of Ae. aegypti were resistant to DDT, deltamethrin and malathion, whereas two other strains (Bangkok and Indian) were susceptible to all four classes of insecticides tested.

Higher esterase activity levels in the resistant compared to the susceptible strains were assumed to be the cause of organophosphate resistance. The combination of DDT and deltamethrin resistance in two strains with normal GST and G6PD characteristics suggests that a kdr‐type nerve insensitivity mechanism may be involved.
Variation in density of cattle‐visiting muscid flies between Danish inland pastures
Authors: JENSEN K.‐M. VAGN , JESPERSEN J. B. , NIELSEN B. OVERGAARD
Published: March 2008

Abstract. The density of cattle‐visiting flies (Muscidae) and the load of black‐flies (Simulium spp.) were estimated in twelve and eighteen inland pastures in Denmark in 1984 and 1985 respectively. No differences in the geographical distribution pattern of the predominant cattle‐visiting Muscidae were recorded, whilst the relative abundance and density of the species and the total fly‐load varied considerably between pastures. In most cases the mean loads of Haema‐tobia irritans (L.) and Hydrotaea irritans (Fall.) on heifers varied significantly in relation to site topography and shelter. These crude site variables explained 65–98% of the variation in densities of horn flies and sheep head flies observed between pastures. Highest densities of Hydrotaea irritans were primarily associated with permanent, low‐lying, fairly sheltered grassland sites, whereas the density was low in temporary, dry, wind‐exposed pastures. A comparable relationship was found for Haematobia irritans. With Haematobosca stimulans (Mg.) and Morellia spp. no relation between grassland environment and fly density was detected.
Allozyme analysis reveals six species within the Anopheles punctulatus complex of mosquitoes in Papua New Guinea
Authors: FOLEY D. H. , PARU R. , DAGORO H. , BRYAN JOAN H.
Published: March 2008

Abstract. Among samples collected from nineteen localities in Papua New Guinea, we have identified six species within the Anopheles punctulatus complex of mosquitoes, by means of cellulose acetate allozyme electrophoresis. An.punctulatus Dönitz sensu stricto was collected from seven villages in the Madang area and from Buksak, Sausi Mission and an area 18 km SW of Tari; An.koliensis Owen from eight villages in the Madang area, from Popondetta and Brown River near Karema; and An.farauti No. 1 from ten coastal areas including Madang, Lorengau, Popondetta, Port Moresby, Rabaul and Wewak. Three newly recognized species, reported here for the first time, are designated as An.farauti No. 4 from Gonoa and Hudini, Madang area; An.farauti No. 5 from Ketarabo near Goroka; and An.farauti No. 6 from Hiwanda near Tari. Three other known members of the complex, An.clowi Rozeboom & Knight, An.farauti No. 2 (Bryan, 1973) and An.farauti No. 3 (Mahon & Meithke, 1982) were not detected in Papua New Guinea. Problems arising with morphological characters for the identification of species in this group are discussed.
Electrophoretic keys to identify members of the Anopheles punctulatus complex of vector mosquitoes in Papua New Guinea
Authors: FOLEY DESMOND H. , BRYAN JOAN H.
Published: March 2008

Abstract. Electrophoretic keys are given for the six species of the Anopheles punctulatus complex (Diptera: Culicidae) known from Papua New Guinea plus An.farauti No. 2 and No. 3 from Australia. The categories ‘faster’, ‘standard’ and ‘slower’ are used in keys to relate allozyme band migration following cellulose acetate electrophoresis to the standard pattern. Alternative keys are given depending on the availability of different species for use as standards.
Ecology of the biting midge Leptoconops albiventris in French Polynesia. III. Influence of abiotic factors on breeding sites. Towards ecological control?
Authors: AUSSEL JEAN‐PHILIPPE
Published: March 2008

Abstract. Correspondance Analysis was used to determine the significant abiotic factors influencing the ecology of the immature stages of Leptoconops albiventris (Diptera: Ceratopogonidae). The breeding places required strict environmental conditions: fine and well‐sorted sand, with low conductivity and humidity. However, the microdistribution of the immature stages within a breeding site does not depend on such factors. Modifying physical parameters in the larval breeding areas might be an important component in future ecological control programmes against L.albiventris populations.
Reproductive success of cat fleas, Ctenocephalides felis, on calves as unusual hosts
Authors: WILLIAMS BERNICE
Published: March 2008

Abstract. Cat fleas, Ctenocephalides felis, were released onto calves as unusual hosts, and sampled at intervals for histological examination. Egg output from fleas on age‐matched male and female calves was monitored. Using indicators of reproductive maturation and regression together with egg output data, the reproductive success and fertility of cat fleas on male and female calves were estimated. Comparisons were made with fleas taken from cats. The mean egg output of fleas on the bull calf was highly significantly different from that on the age‐matched female calf: 28.14 ± 2.96 (SE) eggs/h compared with 16.21 ± 1.96 (SE) eggs/h. A higher proportion of sampled fleas (83.0%) was reproductively mature on the feline hosts compared with the calves (45.4‐62.5%). Blue bodies resulting from oocyte resorption were present in the ovarioles of 10.4‐19.0% of fleas sampled from the calves. No blue bodies were present in fleas removed from cats. Eggs laid by fleas on calves were viable and larvae were reared to adulthood. The mean percentage hatching success on the age‐matched male and female calves was 46.7% and 51.7%. This represents a reduction in viability of 28‐33% compared with eggs laid by fleas on cats. Factors which may account for reduced reproductive maturation of fleas on calves, including protein content of the host's blood, are discussed.
Changes in malathion and pyrethroid resistance after cypermethrin selection of Culex quinquefasciatus field populations of Cuba
Authors: RODRIGUEZ M. , ORTIZ E. , BISSET J. A. , HEMINGWAY J. , SALEDO E.
Published: March 2008

Abstract. Use. of the organophosphorus insecticide malathion for mosquito control in Cuba, for 7 years up to 1986, selected elevated non‐specific esterase and altered acetylcholinesterase (AChE) resistance mechanisms in Culex quinquefasciatus. In central Havana space‐spraying of malathion was replaced by the pyrethroid cypermethrin in 1987: alternate cycles of malathion and cypermethrin were applied in some of the more rural areas of Havana district during 1987‐91. Consequently, populations of Cx quinquefasciatus in the central area of Havana developed resistance to cypermethrin, but there is no evidence of pyrethroid resistance in the outlying areas.

Malathion resistance levels declined significantly after 1986, measured both by bioassay and the frequency of the elevated esterase resistance mechanism, and then stabilized with no measurable decline during 1990 in any of the populations tested. These populations had less than 10% frequency of susceptible homozygotes for both the esterase and AChE resistance mechanisms, indicating that organophosphate resistance is still prevalent in Cuban Cx quinquefasciatus. These two mechanisms appear to be in linkage equilibrium, suggesting that current selection for double resistance is not strong.

In the central Havana region, pirimiphos‐methyl, an organophosphorus insecticide unaffected by the two common malathion resistance mechanisms, is now being used in a resistance management strategy designed to avoid pyrethroid resistance spreading.
Malaria in urban and rural Kinshasa: the entomological input
Authors: COENE J.
Published: March 2008

Abstract. Mosquitoes were collected on human bait over a 16‐month period (September 1988 to December 1989) in an urban and a rural area of Kinshasa, Zaïre. P.falciparum malaria sporozoite rates were determined by ELISA.

In the urban area Culex quinquefasciatus accounts for 96% of the 121 bites/ person/night (b/p/n). The only anopheline is Anopheles gambiae, sensu stricto, with an average of 5.1 b/p/n and a sporozoite rate of 1.86%. The entomological inoculation rate (EIR) averages 0.08 infective b/p/n. Malaria transmission is almost interrupted at the end of the dry season.

In the rural area mosquito nuisance is small (20b/p/n), almost entirely due to six species of Anopheles including four vectors of malaria: An.gambiae (13.3 b/p/n), An.funestus (2.4b/p/n), An.nili (0.4b/p/n) and An.brunnipes (0.7b/p/n) with mean sporozoite rates of 7.85%, 6.60%, 6.63% and 0.53% respectively. An.paludis (0.4b/p/n) and An.hancocki (0.2b/p/n) were not found infective. Malaria transmission is intense and perennial: the overall EIR varies monthly between 0.60 and 3.29 infective b/p/n. The specific contributions of An.gambiae, An.funestus and An.nili average 1.07, 0.14 and 0.03 infective b/p/n respectively.

Malaria transmission peaks during the rainy season in both study areas. The daily mean survival rates for An.gambiae were 0.91 and 0.78 in the rural and urban area, respectively. All An.gambiae examined belonged to the forest cytotype (Coluzzi et al., 1979). Through its effect on the sporozoite rate, the higher vector survival rate in the rural environment appears to be the major determinant of the greater malaria transmission rate in the rural area as compared to urban Kinshasa.
Aspects of sandfly biology in southern Switzerland
Authors: GRIMM F. , GESSLER M. , JENNI L.
Published: March 2008

Abstract. During three field surveys of phlebotomine sandflies in the region of Sessa, Minor Malcantone, southern Switzerland, annually 1987‐89, Phlebotomus pemiciosus and P.mascittii were caught regularly by means of light traps, but only when the traps were in close association with humans. The most productive catching sites were in the middle of Sessa village, in basements or partially closed shelters in the immediate vicinity of human dwellings. All catching sites outside the village were negative. The only other sandfly species caught was Sergentomyia minuta, four specimens only. P.pemiciosus and P.mascittii always occurred together and were found to feed ‐ at least occasionally – on human blood. Glucose and fructose were identified in wild‐caught sandflies of both species. A breeding place of P.mascittii was identified in the basement of a house in the middle of Sessa. Analyses of soil samples revealed moderately loamy humus with a slightly acidic pH (5.6).
Changes in immunity to Ixodes ricinus by rabbits infested at different levels
Authors: SCHORDERET S. , BROSSARD M.
Published: March 2008

Abstract. Two groups of rabbits were infested twice with different numbers of Ixodes ricinus adults: one group (high infestation) with twenty‐five females and twenty‐five males and the other group (low infestation) with five pairs. A third infestation was performed in both groups with fifteen adult pairs. Tick biology was monitored for resistance effects. At the second infestation, the feeding and the egg production were more perturbed in ticks fed on high infestation rabbits. The embryogenesis was only affected in ticks from high infestation rabbits. At the third infestation, resistance was increased only in low infestation rabbits, which became more resistant than high infestation rabbits. The blastogenic response of peripheral blood lymphocytes and antibody production against ticks were assessed. A salivary gland extract and an integumental antigen from Lricinus adult females were able to initiate lymphocyte proliferation. The response was significantly higher in high infestation rabbits, especially at the end of the second infestation, and higher in low infestation rabbits during the third infestation. Non‐specific proliferation with concanavalin A was temporarily decreased in both rabbits groups during the first and the second infestations. Specific antibody response to salivary and integument antigens were always the highest in high infestation rabbits. The involvement of tick‐induced immunosuppression is discussed.
Analysis of mosquito bloodmeals by DNA profiling
Authors: GOKOOL SUZANNE , CURTIS C. F. , SMITH DEBORAH F.
Published: March 2008

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 female Anopheles gambiae Giles 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 the huts.
Comparison of two sampling methods for domestic populations of Triatoma infestans in north‐west Argentina
Authors: GURTLER RICARDO E. , SCHWEIGMANN NICOLAS J. , CECERE MARIA C. , WISNIVESKY‐COLLI CRISTINA , CHUIT ROBERTO
Published: March 2008

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 vector Triatoma infestans (Klug) (Hemiptera: Reduviidae), two knockdown (KD) insecticidal collection procedures were compared with the standard flush‐out (FO) method for sampling T. 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./m2 in 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 of T.infestans large 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 of speed and standardization.
Effects of the fungus Aspergillus penicillioides on the house dust mite Dermatophagoides pteronyss'mus: an experimental re‐evaluation
Authors: HAY D. B. , HART B. J. , DOUGLAS A. E.
Published: March 2008

Abstract. In this report the widely‐held view that house dust mites benefit from fungal contamination of the dietary substratum is re‐examined. The performance of Dermatophagoides pteronyssinus (Acari: Pyroglyphidae) is documented over two successive generations in the presence or absence of the xerophilic fungus Aspergillus penicillioides (Hyphomycetales: Moniliaceae). This fungus reduced survival, development rate, adult length and fecundity of D.pteronyssinus. Detrimental effects of A.penicillioides were proportional to the fungal density. Despite the antagonistic effects of A.penicillioides, a requirement for the fungus was indicated by the poor performance of fungus‐free mites in the second generation; sustained culture of D.pteronyssinus in the absence of fungi is probably not possible. It is suggested that fungi may alter the particulate nature of the substratum to the detriment of house dust mites, but also provide micronutrients deficient in the diet.
Epidemiology of bluetongue in Central America and the Caribbean: initial entomological findings
Authors: GREINER ELLIS C. , MO CLAUDETTE L. , HOMAN E. JANE , GONZALEZ JOHNNY , OVIEDO MARCO‐TULIO , THOMPSON L. H. , GIBBS E. P. J.
Published: March 2008

Abstract. Forty‐four species of Culicoides (Diptera: Ceratopogonidae) were caught in insect light traps during the first 2 years of studies on the epidemiology of bluetongue virus in the Caribbean and Central America. Traps were operated near sentinel ruminants which were bled monthly for serologic evaluation and then virus isolation. More than 570,000 individuals were identified. Culicoides insignis Lutz accounted for 90% of the catch, C.filarifer Hoffman/C.ocumarensis Ortiz 5%, C.furens Poey 3% and C.pusillus Lutz 2%. Other species accounted for less than 1% of the total catch. Sentinel ruminants became seropositive when C.insignis populations were high at many study sites. At a few sites C.pusillus and C.filarifer I C.ocumarensis were predominant or were present in large numbers during seroconversions of sentinels. Virus isolations were obtained from sentinel ruminants during times when these same species were present in large populations.
Effective population size and persistence of Anopheles arabiensis during the dry season in West Africa
Authors: TAYLOR CHARLES E. , TOURE YEYA T. , COLUZZI MARIO , PETRARCA VINCENZO
Published: March 2008

Abstract. The way that the malaria vectors Anopheles arabiensis and An.gambiae survive the dry season in sub‐saharan Sahel or northern Savanna areas of Africa remains enigmatic. We examined this problem by calculating the effective sizes (Ne) of An.arabiensis populations for several locations in West Africa. An indirect/genetic procedure was used, comparing gene frequencies at several time intervals. The amount of drift which occurred provides an estimate of Ne. Most estimates of Ne were approximately 2000 individuals, probably close to the yearly minimum. This supports the hypothesis that populations of An.arabiensis in this region are continuous throughout the year, with many individuals surviving through the dry season, perhaps in a physiologically altered state, rather than extinction or severe bottlenecks during the dry season, followed by recolonization by a few individual survivors or immigrants in the subsequent rainy season.
A comparison of susceptibility of two allopatric populations of Glossina pallidipes for stocks of Trypanosoma congolense
Authors: MOLOO S. K.
Published: March 2008

Abstract. A colony of Glossina pallidipes Austen which originated from Nguruman, Rift Valley Province, Kenya, was significantly more susceptible to infection (19.3%) with a stock of Trypanosoma congolense Broden isolated from G. pallidipes in Nguruman than a colony of the same species which originated from Shimba Hills, Coast Province, Kenya (5.6%). Male G. pallidipes from Nguruman were significantly more susceptible than females to this T. congolense stock whilst the susceptibility of both sexes of G. pallidipes from Shimba Hills did not differ significantly. All six goats on which six infected G. pallidipes fed singly (three tsetse per colony) became infected. Similarly, the G. pallidipes colony of Nguruman origin was significantly more susceptible to infection (16.4%) with a stock of T. congolense isolated from G. pallidipes in Shimba Hills than the colony of Shimba Hills origin (4.9%). The susceptibility of the sexes of G. pallidipes from both the colonies to this stock of T. congolense did not differ significantly. Again, all six goats on which six infected G. pallidipes fed singly (three tsetse per colony) became infected. If the observed differences in susceptibility of the two G. pallidipes colonies reflect transmission of trypanosomes by the two allopatric populations of tsetse in the field, then the epidemiology of congolense‐trypanosomiasis in livestock must differ between these two areas of Kenya endemic for trypanosomiasis.
Confirmation that Plasmodium falciparum has aperiodic infectivity to Anopheles gambiae
Authors: GITHEKO A. K. , BRANDLING‐BENNETT A. D. , BEIER M. , MBOGO C. M. , ATIELI F. K. , OWAGA M. L. , JUMA F. , COLLINS F. H.
Published: March 2008

Abstract. In preparation for field studies of transmission‐blocking malaria vaccines, a study was carried out to determine whether P. falciparum infections obtained in An. gambiae blood‐fed at 16.00 hours were quantitatively similar to infections obtained at 23.00 hours. Using a group of children aged 5‐12 years from villages at Ahero, near Kisumu in Kenya, 71/74 (96%) of whom were found to be positive for P. falciparum parasitaemia, one batch of fifty colony‐bred An. gambiae females were fed on volunteers at 16.00 hours and another batch at 23.00 hours. No statistically significant differences were found in the proportions of mosquitoes becoming infected, the numbers of children infecting mosquitoes or the mean numbers of malaria oocysts developing in mosquitoes blood‐fed at the different times. Because mosquito infections obtained by day (16.00 hours) are equivalent in quantity to those obtained at night (23.00 hours), experimental infections can be carried out in the afternoon, when it is most convenient, rather than during the night.
Vectors of cutaneous leishmaniasis in north‐central Venezuela
Authors: FELICIANGELI M. DORA , RODRIGUEZ NORIS , BRAVO ARTURO , ARIAS FREDDY , GUZMAN BERNARDO
Published: March 2008

Abstract. An entomological survey was undertaken from January 1991 to February 1992 in El Ingenio, Miranda State, Venezuela, an endemic area of cutaneous leishmaniasis: prevalence of 10.7 cases per 100,000 inhabitants.

A total of 4863 female sandflies (Phlebotominae) of fourteen species were collected in Shannon traps, then dissected and examined for leishmanial infections.

Lutzomyia ovallesi (85.4%) and Lu. gomezl (11.2%) were the predominant anthropophilic species of sandfly. Fifty‐one (1.19%) Lu. ovallesi and two(0.47%) Lu. gomezi had natural infection with Leishmania promastigotes. Identification of the parasites was done by using the polymerase chain reaction (PCR) and DNA hybridization. Two isolates from Lu. gomezi and forty‐nine from Lu. ovallesi were typed as Leishmania braziliensis and three of the latter reacted with Le. mexicana also. This is the first report of Lu. gomezi with parasites typed as Le. braziliensis.

We concluded that Lu. ovallesi is the primary vector of cutaneous leishmaniasis in the north‐central area of Venezuela and Lu. gomezi should be regarded as an additional vector.
Genetics of two colonies of Glossina pallidipes originating from allopatric populations in Kenya
Authors: GOODING R. H. , MOLOO S. K.
Published: March 2008

Abstract Two large colonies, originating from allopatric populations of Glossina pallidipes Austen, in the Shimba Hills and Nguruman, Kenya, which differ biologically and with respect to vectorial competence, were compared at fourteen enzyme loci using polyacrylamide gel electrophoresis. The colonies had similar levels of genetic diversity with approximately half of the loci being polymorphic, an average of 1.6‐1.7 alleles per locus, and a mean heterozygosity per locus of approximately 18.4%. However, the colonies differed significantly in allele frequencies at the loci for phosphoglucomutase, glucose‐6‐phosphate dehydrogenase, xanthine oxidase, octanol dehydrogenase and phosphoglucose isomerase. The results were compared with earlier studies on this species and no evidence was found for selection of specific alleles during establishment or maintenance of colonies of G.pallidipes, nor were specific chromosomes, or marker genes, associated with the biological differences between the two colonies.
Size variation and reproductive success in the mosquito Aedes cantans
Authors: RENSHAW M. , SERVICE M. W. , BIRLEY M. H.
Published: March 2008

Abstract. A link between density‐dependent larval competition and adult size of the mosquito Aedes cantans was demonstrated in northern England. Ponds containing high larval densities produced smaller larvae which, in turn, resulted in smaller adults at emergence.

In both 1989 and 1990, parous mosquitoes caught at human bait were larger than nulliparous ones, suggesting that larger mosquitoes are more successful at host location and egg‐laying and also that they may be longer lived.

Larger mosquitoes produced larger egg clutches than smaller females: however, there was no difference in the size of eggs laid by large and small females.
Sugars in the alimentary canal of Lutzomyia youngi (Diptera: Phlebotominae)
Authors: AÑEZ N. , LUGO A. , LOAIZA A. , NIEVES E. , OROZCO J.
Published: March 2008

Abstract. Gas chromatography (GC) analysis of 159 specimens (144 females and 15 males) of Lutzomyia youngi collected 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 on Leishmania–wector relationships.
Relative potency of DEPA as a repellent against the sandfly Phlebotomus papatasi
Authors: KALYANASUNDARAM M. , SRINIVASAN R. , SUBRAMANIAN S. , PANICKER K. N.
Published: March 2008

Abstract. The insect repellent N,N‐diethylphenylacetamide (DEPA) was compared with two commercial repellents, N,N‐diethyl‐m‐toluamide (DEET) and dimethyl phthalate (DMP), for protection against 3‐day‐old unfed females of the sandfly Phlebotomus papatasi (Scopoli) under laboratory conditions, using host rabbits. Both DEPA and DEET were found to be more effective than DMP, but there was no significant difference between the efficacy of DEPA and DEET.
Aggregated oviposition in the Simulium damnosum complex is mediated by eggs in a laboratory bioassay
Authors: McCALL P. J. , TREES A. J. , WALSH J. F. , MOLYNEUX D. H.
Published: March 2008

Abstract. . The phenomenon of aggregated oviposition in blackflies (Diptera: Simuliidae) was investigated under controlled laboratory conditions, using wild‐caught females of the Simulium damnosum complex in Sierra Leone. A method was developed for inducing Simulium females to lay eggs, and used as a bioassay to measure the responses of gravid S. damnosum s.l. to freshly laid eggs of the same species complex. In a series of two‐choice tests, significantly more ovipositing flies chose substrates already containing eggs over control substrates (P= 0.004). The time from introduction of flies into the oviposition system to the onset of egg‐laying was significantly less when eggs were already present (P= 0.049). Flies responded more quickly when more eggs were present and the relationship between egg‐batch number and the time of this response was curvilinear (P= 0.012). Ecological advantages and disadvantages of such aggregation behaviour and the possible role of semiochemicals in its mediation are discussed.
Midgut lectin activity and sugar specificity in teneral and fed tsetse
Authors: WELBURN SUSAN C. , MAUDLIN IAN , MOLYNEUX DAVID H.
Published: March 2008

Abstract. . Midgut infection rates of Trypanosoma congolense in Glossina palpalis palpalis and of Trypanosoma brucei rhodesiense in Glossina pallidipes are potentiated by the addition of D+ glucosamine to the infective feed, but not to the levels of super‐infection reported for G. m. morsitans. G. p. palpalis and G.pallidipes are shown to possess two trypanocidal molecules: a glucosyl lectin which can be inhibited by D+ glucosamine and a galactosyl molecule inhibited by D+ galactose. Addition of both D+ glucosamine and D+ galactose to the teneral infective feed promotes super‐infection of the midguts of G.p.palpalis. The glucosyl lectin is specific for rabbit erythrocytes and is present in guts of fed G.m.morsitans and G.p.palpalis, titres of lectin activity do not increase substantially after the second bloodmeal. The galactosyl specific molecule does not show any erythrocyte specificity, although haemolytic activity is observed only in G.p.palpalis and not in G.m.morsitans. The presence of two trypanocidal molecules in some species of tsetse may account for the innate refractoriness of these flies to trypanosome infection.

As D+ glucosamine also inhibits the killing of procyclic trypanosomes taken as an infective feed, it is suggested that the midgut lectin is normally responsible for the agglutination of trypanosomes in the fly midgut by binding to the pro‐cyclic surface coat, prior to establishment in the ecto‐peritrophic space.
Correlates of the peridomestic abundance of Lutzomyia longipalpis (Diptera: Psychodidae) in Amazonian Brazil
Authors: QUINNELL R. J. , DYE C.
Published: March 2008

Abstract. Abundance of the sandfly Lutzomyia longipalpis, the vector of Leishmania chagasi, was surveyed using CDC light‐suction traps in fifteen villages and 180 homesteads on Marajo island, Para State, Brazil. Flies were most abundant in cultivated areas, secondary growth and open woodland, away from savanna grassland and forest. Within homesteads, the abundance of flies in animal sheds was weakly associated with the number of hosts kept therein, and inversely related to the number elsewhere, both human and animal. Houses harboured more flies if dogs were present and if the house had: a roof of thatch rather than of tiles or tin; a thatched roof which had not been treated with insecticide; relatively more holes in walls and roof. The sex ratio of flies was more male‐biased at higher densities. We weigh the importance of these variables as risk factors for Le.chagasi infection.
Comparative study of mouthparts of four species of Culicoides from Tibet
Authors: McKEEVER STURGIS , HAGAN DANIEL V. , WANG XUYONG
Published: March 2008

Abstract. Mouthparts of four species of Culicoides from Tibet were studied by light and scanning electron microscopy (SEM). Photomicrographs were made of the mandible, labrum, hypopharynx, lacinia, and the sensory pit of the third palpal segment for each of the four species. Values for eighteen characters of five structures are presented graphically.

Mean values for ten of the eighteen characters evaluated were significantly greater for C.circumscriptus and C.mamaensis than for C.maculatus and C.tibetensis. Photomicrographs revealed specific differences in camber and pitch of the fifth mandibular tooth, in size and location of the subapical labral sensillae, in size of the teeth of the hypopharynx, and in size and depth of the palpal sensory pit and number of sensillae per pit.
Population dynamics of anthropophilic mosquitoes during the northeast monsoon season in the malaria epidemic zone of Sri Lanka
Authors: RAMASAMY M. S. , KULASEKERA R. , SRIKRISHNARAJ K. A. , RAMASAMY R.
Published: March 2008

Abstract. Mosquito‐borne diseases are a major health problem in Sri Lanka. Human biting mosquitoes were collected during the night (18.00–06.00 hours) at Nikawehera village, in the malaria endemic intermediate rainfall zone of the country. Collections were made at monthly intervals in the period October 1991 to April 1992, which included the main rainy season due to the northeast monsoon (October‐January). Thirteen Anopheles, eleven Culex, three Aedes, three Mansonia and one Armigeres species were identified, including known vectors of malaria, Bancroftian filariasis, Japanese encephalitis and dengue fever. Mosquito human‐biting rates were highest in December. The main malaria vector Anopheles culicifacies showed peak biting between 18.00 and 23.00 hours whereas the predominant culicines Culex fuscocephala and Cx quinquefasciatus preferred to bite after midnight. In 1991‐92 the prevalence of some species of anophelines at Nikawehera differed markedly from that observed in 1990‐91 and the possible reasons are discussed.
Host choice of anopheline mosquitoes in a malaria endemic area of western Venezuela
Authors: RUBIO‐PALIS YASMIN , CURTIS CHRISTOPHER F. , GONZALES CLEMENCIA , WIRTZ ROBERT A.
Published: March 2008

Abstract. Bloodmeals of exophilic anopheline mosquitoes collected resting on vegetation in a malaria endemic area in western Venezuela were identified by ELISA. Using a TMB peroxidase substrate in the ELISA, human bloodmeals were readily identified up to 40 h after ingestion in all laboratory‐fed mosquitoes tested. Assay sensitivity declined to 75% identifiable 44 h post‐feeding.

The Human Blood Index and the Feeding Index of each species differed between the three villages studied. An.triannulatus was generally more anthropophilic than An.nuneztovari and An.oswaldoi. These contrasting results emphasize the difficulties of interpreting host choice data.
Structure and function of the cibarial armature in Simuliidae
Authors: REID G. D. F.
Published: March 2008

Abstract. Cibarial armature morphology in adult female blackflies (Diptera: Simuliidae) is described using scanning electron microscopy. Three distinct types of armature are recognized, comprising those with teeth, e.g. Simulium ochraceum, S. ornatum, S. veracruzanum and S. vorax; those with spicules, e.g. Austrosimulium bancrofti, S.damnosum, S.exiguum, S.metallicum and S.neavei; and those lacking these projections, e.g. Prosimulium rufipes and S.lineatum.

Whereas the armature is poorly developed in vectors of human onchocerciasis such as S. damnosum, S. exiguum, S. metallicum and S. neavei, the well‐developed armature in S. ochraceum, S. veracruzanum and S. vorax does not prevent these species becoming infected with Onchocerca spp. (Nematoda: Onchocercidae). Hence the armature is not primarily a mechanism to counteract microfilaria superinfection.

Since cibarial armatures are more developed in the haematophagous females than in the males of certain Families of flies, e.g. Ceratopogonidae, Culicidae, Phlebotominae and Simuliidae in the sub‐order Nematocera, evidently the armature has evolved in response to the blood‐feeding habit. As the suction of imbibed blood by the cibarial pump may require a valve mechanism to prevent back‐flow, it is suggested that the armature is primarily for this purpose. Secondarily, the cibarial armature presents a damaging barrier against ingested microfilariae.
Analysis of stage‐specific and shared antigens derived from Rhipicephalus sanguineus by electrophoresis and Western blotting
Authors: HERNÁNDEZ R. MARTÍN , HOYO C. CUELLAR DEL , GARCIA A. S. OLMEDA , RODRÍGUEZ RODRÍGUEZ
Published: March 2008

e carried out an SDS‐PAGE analysis of antigens of Rhipicephalus sanguineus using extracts of eggs (EE), larvae (LE), nymphs (NE), male salivary glands (MSGE), male midguts (MME), female salivary glands (FSGE) and female midguts (FME). Under non‐reducing conditions a common band of about 205 kDa was observed. EE, LE and NE extracts showed groups of bands between 150 and 75 kDa. A protein pattern was observed in FSGE extract with a group of bands between 75 and 50 kDa and four bands between 15 and 6.5 kDa. In this case an apparently exclusive band of molecular weight about 25 kDa was observed. Under reducing conditions similarities between LE and NE extracts increased, separating from the EE pattern. On the other hand, we have determined the presence of stage‐specific and common antigens on EE, LE, NE, MSGE, MME, FSGE and FME extracts of R.sanguineus by means of immunoblots using polyclonal sera of rabbits infested with larvae, nymphs or adults of this tick. EE extract was only recognized by the anti‐larva sera. Higher reactivity was observed when the extracts were tested with anti‐adult sera. In these experiments a very prominent band of molecular weight about 45 kDa was detected. This band was not observed under reducing conditions. Higher reactivity with anti‐adult sera was observed against FSGE extract.