bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative use of bendiocarb and DDT to control Anopheles pseudopuncitpennis in a malarious area of Mexico
Authors: LOYOLA ENRIQUE G. , VACA MIGUEL A. , BOWN DAVID N. , PÉREZ ENRIQUE , RODRIGUEZ MARIO H. 
Published: March 2008

Abstract. The state of Sinaloa has one of the highest and most persistent malaria transmission levels in Mexico. Due to this situation, with resistance of the vector Anopheles pseudopunctipennis Theobald to DDT, the carbamate insecticide bendiocarb was evaluated as an alternative to DDT for residual house‐spraying in village‐scale trials during 1985–87. Application rates of the active ingredient per square metre of sprayable surface (ai/m2) were 0.4 g bendiocarb 80% wettable powder (80WP) and 2g DDT 75% WP.Both insecticides failed to control mosquito populations. Human‐bait mosquito densities were not altered as a result of insecticide spraying and human‐bait collected mosquito mortality rates were low, suggesting little pre‐biting insecticide contact due to avoidance or insufficient resting time indoors. Lower densities of indoor‐resting mosquitoes were observed with DDT as opposed to bendiocarb treated houses. Anopheline mortality was higher (98–100%) when exposed for 1 h to 1% bendiocarb in standard WHO susceptibility tests and wall bioassays. Mortality‐rates of 15–48% due to lh exposure to 4% DDT indicated that this insecticide may continue to be partially effective. House curtain and mark‐recapture mosquito studies indicated that DDT produced higher excito‐repellency than bendiocarb, as reflected by more mosquito landings but lower feeding rates, shorter resting period and earlier exit time from DDT sprayed houses.In the absence of insecticide, more than 50% of blood‐fed An.pseudopunctipennis females exited from houses within 2–Ah of release, showing exophilic behaviour. The outdoor/indoor density ratio indicated that the majority were exophagic. These behavioural characteristics limit the usefulness of any residual insecticide against An.pseudopunctipennis.
Prehibernation diet and reproductive condition of female Anopheles messeae in Sweden
Authors: THOMAS G. , JAENSON T. , AMENESHEWA BIRKINESH 
Published: March 2008

Abstract.

Blood and sugar feeding in the mosquito Anopheles messeae Falleroni were investigated near Uppsala, Sweden, from 1981 to 1985, with emphasis on prehibernation diet.
Fructose, indicating plant feeding, was present in females of all ovarian stages, from April to October, and contributed to fat body development in non‐gonoactive females before hibernation.
An.messeae males and females (inseminated and uninseminated) were observed feeding on floral nectaries of the plants Achillea millefolium L. and Tanacetum vulgare L. at night during August.
Gonotrophic dissociation started in some females in July, and by the end of September all females were inseminated and nulliparous but non‐gonoactive.
Animal sheds were used as diurnal resting sites of non‐gonoactive, prehibernating female An. messeae. Among recently fed mosquitoes in that group, 85% were gut positive for fructose and 15% for blood. Most of them showed negative host tropism, indicating that bloodfeeding is not a prerequisite for hibernation.
Survival rates of bloodfed (48 ± 31 days) and non‐bloodfed (42 ± 21 days) females, collected from a cattle shed in September and kept caged without food or water in a store house, were not significantly different. This indicates that bloodfeeding may occur facultatively before hibernation but does not affect longevity and survival.
If overwintering is possible for bloodfed An.messeae females, they would be more likely vectors of pathogens such as Batai virus.
Pyrethroid‐treated bednet effects on mosquitoes of the Anopheles gambiae complex in The Gambia
Authors: LINDSAY S. W. , ADIAMAH J. H. , MILLER J. E. , ARMSTRONG J. R. M. 
Published: March 2008

Abstract. The response of Anopheles gambiae complex mosquitoes to men sleeping under insecticide‐impregnated or untreated bednets in six verandali trap huts was studied during the dry season in The Gambia. With this type of hut it was possible to collect live and dead indoor‐resting mosquitoes and estimate the number of wild mosquitoes which entered, bloodfed on man, and exited each night. Bednets were treated with emulsions targetted to leave deposits of 25mg/m2 lambda‐cyhalothrin, or 5,50 or 500 mg/m2 permethrin, diluted from emulsifiable concentrates (EC), or a blank formulation similar to the EC except that the permethrin was omitted; the sixth net was left untreated. Nets and sleepers were rotated between huts on different nights, the design being based on a series of Latin squares and conducted double‐blind.Permethrin‐impregnated bednets deterred mosquitoes from entering the huts. The degree of deterrency was proportional to the dosage of permethrin. This effect was also caused by the blank formulation and therefore attributed to other components of the formulation, rather than to the permethrin itself. The net impregnated with 500 mg permethrin per square metre gave the best individual protection, reducing mosquito bloodfeeding by 91% compared with untreated nets. However, lambda‐cyhalothrin was proportionately more insecticidal than permethrin at doses of equivalent deterrency. At this stage of research, it remains conjectural whether chemical deterrency or killing of malaria vectors is better for community protection.
Relations between Anopheles darlingi breeding habitats, rainfall, river level and malaria transmission rates in the rain forest of Suriname
Authors: ROZENDAAL J. A. 
Published: March 2008

Abstract. Irregular peaks of P.falciparum malaria incidence were monitored in Suriname during 1982‐86. An attempt is made to correlate these fluctuations of malaria rates with rainfall and river level in relation to the periodic availability of breeding habitats for the malaria vector Anopheles darlingi Root.Densities of adult female An. darlingi were recorded in the Upper‐Marowijne region of Suriname, in a focus of malaria along the Marowijne River. Peaks in biting densities correlated well with periods of (i) high water level in the long rainy season, (ii) low water level in the long dry season, and (iii) abundant rainfall in the short rainy season. Critical levels of river‐height and rainfall were defined which could explain most of the monthly fluctuations in malaria parasite incidence observed in this area.
Studies on vectors of Trypanosoma cruzi in Trinidad, West Indies
Authors: OMAH‐MAHARAJ INDIRA 
Published: March 2008

Abstract.Studies on vectors ofTrypanosoma cruziChagas were conducted during 1982‐85 as part of an investigation on the epidemiological status of American Trypanosomiasis in Trinidad, West Indies. A total of 148 reduviid bugs were collected from caves, armadillo nests and at light traps, comprising four sylvatic species and totalling 120Panstrongylus geniculatus(Latreille), twoP.rufotuberculatus(Champion), twelveRhodnius pictipesStal and fourteenEratyrus mucronatusStal.A significantly higher level of infection withT.cruziwas recorded forP. geniculatus(42.5%) compared toR.pictipes(8.3%). The other two bug species were not found to be infected.P.geniculatusseems to be the most important vector in the sylvatic cycle of transmission ofT.cruziin Trinidad.
Modelling the effect of feeding‐related mortality on the feeding strategy of tsetse (Diptera: Glossinidae)
Authors: RANDOLPH SARAH E. , WILLIAMS BRIAN G. , ROGERS DAVID J. , CONNOR HILARY 
Published: March 2008

Abstract. Free‐living haematophagous insects risk death through host grooming responses or through increased susceptibility to predation whenever they take a bloodmeal. In this paper we investigate the effects of these risks on the feeding strategy of tsetse. A model is presented that allows for death of tsetse by starvation if they do not succeed in feeding within a fixed time (set at 6 days in the first instance) and for mortality specifically associated with feeding. In addition there is background mortality that applies to all flies at all times.The model is used to compute the individual life‐time fertility (number of female puparia per female) as a function of the probability of obtaining a meal (indicated by field data to be very high, usually > 0.85 per day) and the day on which flies start to search for a meal. We suggest that the feeding strategy that would be selected for is that which allows the maximum reproductive output. The model shows that this strategy involves making no attempts to feed for 3–4 days after the previous meal and then attempting to feed with the greatest possible probability until a meal is obtained. The predicted feeding interval, obtained independently of any trapping data, agrees closely with all previous estimates from field studies using a variety of methods. Preliminary results from a laboratory experiment reveal an increased risk of predation of recently fed as compared with hungry tsetse. The lower the actual feeding mortality the more frequently will flies be able to feed should conditions so demand. It is adaptive, however, for tsetse to delay attempting to feed for as long as they can, which is made possible by the near certainty of locating and feeding on a host within 1 day, using their sophisticated sensory systems.
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

AbstractFemale 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

AbstractApplications 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

AbstractA 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

AbstractAmong 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

AbstractRecordings 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

AbstractWater 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

Abstract. 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.
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.