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current status of anopheles stephensi response to various insecticides in some areas of the thar desert.investigations on the current response of a. stephensi. to six insecticides viz. ddt, dieldrin, malathion, fenitrothion, propoxur and permethrin, were carried out in 3 districts i.e. barmer, jodhpur and pali, of the thar desert. the species was found resistant to ddt and dieldrin, partially resistant to malathion and susceptible to fenitrothion, propoxur and permethrin. dieldrin and malathion resistance has been detected for the first time in the thar desert. lethal concentrations (lc50 & lc95) ...19968707370
mosquitoes (diptera:culicidae) breeding in brackish water: female ovipositional preferences or larval survival?four species of mosquitoes were abundant in concrete reservoir tanks containing brackish water that ranged from 16 to 39% sea water. the ability of the larvae to survive in various salinities was compared for each species with the ovipositional preferences of the adult females to determine whether the 2 traits were correlated. southern house mosquito, culex quinquefasciatus say, normally was not present in the tanks but survived well in salinities up to 25% sea water. however, gravid females alm ...19968699444
experimental evidence against replication or dissemination of hepatitis c virus in mosquitoes (diptera:culicidae) using detection by reverse transcriptase polymerase chain reaction.in 3 laboratory experiments, mosquitoes were fed hepatitis c virus (hcv)-rna positive blood by using membrane feeders, separated into head, thorax, and abdomen, and tested by a reverse transcriptase polymerase chain reaction for hcv-rna. hcv did not replicate or disseminate in mosquitoes that had ingested blood from patients that were hcv-viremic positive. when yellow fever mosquitoes, aedes aegypti (l.), were held for 1, 3, 7, 14, and 21 d after feeding, hcv-rna was detected in the abdomens of ...19968667387
cloning and expression of the first anaerobic toxin gene from clostridium bifermentans subsp. malaysia, encoding a new mosquitocidal protein with homologies to bacillus thuringiensis delta-endotoxins.a gene (cbm71) encoding a 71,128-da mosquitocidal protein (cbm71) was obtained by screening a size-fractionated xbai digest of total genomic dna from clostridium bifermentans subsp. malaysia ch18 with two gene-specific oligonucleotide probes. the sequence of the cbm71 protein, as deduced from the sequence of cbm71, corresponds to that of the 66-kda protein previously described as one of the mosquitocidal components of c. bifermentans subsp. malaysia. cbm71 shows limited similarities with bacillu ...19968655486
the nigerian i/cdc strain of plasmodium ovale in chimpanzees.the chimpanzee is the only animal host currently available that can support the development of the human malaria parasite plasmodium ovale. thirty-one infections with the nigerian i/cdc strain were induced in splenectomized chimpanzees. maximum parasite counts ranged from 1,240 to 127,224/microliters. infections were transient and unpredictable. anopheles stephensi, anopheles gambiae, anopheles freeborni, and anopheles dirus mosquitoes were infected by feeding through parafilm membranes on hepar ...19968636850
sodium beta-artelinate--a new potential gametocytocide.the water-soluble artemisinin analogue sodium beta-artelinate, a fast-acting blood schizontocide, was evaluated for gametocytocidal action against simian malaria plasmodium cynomolgi b, and a single dose of the compound has been found to be an effective gametocytocide by both oral and intravenous routes. the compound was able to sterilize the circulating gametocytes in rhesus monkey, resulting in loss of mosquito infectivity and oocyst development in the anopheles stephensi. however, no sporonto ...19968631376
bacterial population dynamics in three anopheline species: the impact on plasmodium sporogonic development.the functional role of bacteria in the midgut of adult mosquitoes is unknown. in this study, we examined the population dynamics of midgut bacteria of laboratory reared anopheles stephensi, an. gambiae, and an. albimanus. mosquito midguts were dissected under sterile conditions and examined for the presence of bacteria using standard microbiologic techniques. ninety percent and 73% (n = 30) of newly emerged an. gambiae and an. stephensi, respectively, harbored bacteria. in contrast, only 17% (n ...19968619451
cloning and sequencing of a cdna encoding acetylcholinesterase in colorado potato beetle, leptinotarsa decemlineata (say).a cdna encoding acetylcholinesterase (ache, ec 1.1.1.7) was cloned from a cdna library constructed from an insecticide-susceptible strain of colorado potato beetle, leptinotarsa decemlineata (say). the complete amino acid sequence of ache deduced from the cdna consisted of 29 residues for the putative signal peptide and 600 residues for the mature protein with a predicted molecular weight of 67,994. northern blot analysis of poly(a) rna showed an approx 13.1-kb transcript. the mature protein seq ...19958580913
plasmodium yoelii nigeriensis: the effect of high and low intensity of infection upon the egg production and bloodmeal size of anopheles stephensi during three gonotrophic cycles.anopheles stephensi mosquitoes showed a reduction in fecundity over 3 successive gonotrophic cycles, after becoming infected with plasmodium yoelii nigeriensis. this effect could be observed at high oocyst burdens (> 75) or at low oocyst burdens (mean of 4.36). mean bloodmeal size of the infected mosquitoes was significantly reduced only when feeding upon a mouse with a high gametocytaemia and the conversion of the bloodmeal into eggs by the infected mosquitoes was disrupted. patterns of infecte ...19958559587
the impact of variations in temperature on early plasmodium falciparum development in anopheles stephensi.the effect of temperature on early plasmodium falciparum development was examined in anopheles stephensi. the rates of both ookinete development and bloodmeal digestion were lengthened as temperatures decreased from 27 to 21 degrees c. however, low temperatures (21-27 degrees c) did not significantly influence infection rates or densities of either ookinetes or oocytes. in contrast, high temperatures (30 and 32 degrees c) significantly impacted parasite densities and infection rates by interferi ...19958559585
[effect of environmental temperature, cryopreservation and aging on plasmodium vivax sporozoites developing into exoerythrocytic stages].after anopheles stephensi mosquitoes with salivary infection of plasmodium vivax were put in environments with temperatures of 30 +/- 1 degrees c, 26 +/- 1 degrees c or 13 +/- 1 degrees c for 5 d, their glands were aseptically dissected and sporozoites were collected and inoculated into hepg2-a16 cell monolayers. seven days post-inoculation the cultured materials were harvested and the exoerythrocytic schizonts and hypnozoites were observed under the microscope by using immunoperoxidase staining ...19958556788
characterization of six highly mosquitocidal bacillus thuringiensis strains that do not belong to h-14 serotype.four strains belonging to bacillus thuringiensis serovars thompsoni, malaysiensis, canadensis, jegathesan and two auto-agglutinating b.t. strains were identified as being highly toxic to the mosquito larvae of the species aedes aegypti, anopheles stephensi, and culex pipiens. their larvicidal and hemolytic activities were determined and compared with those of strains known to be highly mosquitocidal and/or cytolytic from serovars of b.t. israelensis, morrisoni, darmstadiensis, medellin, kyushuen ...19968555944
probing and gorging responses of three mosquito species to a membrane feeding system at a range of temperatures.membrane feeding of 3 mosquito species, aedes aegypti, anopheles stephensi, and anopheles arabiensis, with formulated protein meals was carried out at a range of temperatures. the response was evaluated in terms of probing after 5 min, engorgement after 90 min, and 50% feeding time. aedes aegypti showed a satisfactory feeding response across the complete temperature range investigated, 28-40 degrees c, although engorgement was significantly faster between 36 and 40 degrees c. anopheles stephensi ...19958551304
isolation of the insecticidal components of tagetes minuta (compositae) against mosquito larvae and adults.application of tagetes minuta floral extract to silica gel column chromatography produced 2 fractions with the hydrogenate part 20-30 times more toxic to larvae and 12-13 times more toxic to adults of aedes aegypti and anopheles stephensi, respectively, than the oxygenate part. further fractionation by column chromatography of the hydrogenate fraction produced 4 thiophenes, 5-(but-3-ene-1-ynyl)-2,2'-bithiophene, 5-(but-3-ene-1-ynyl)-5'-methyl-2,2'-bithiophene, 2,2',5',2"-terthiophene, and 5-meth ...19958551298
larvicidal activity of a few plant extracts against culex quinquefasciatus and anopheles stephensi.larvicidal activity of partially purified extracts of leaves of vitex negundo, nerium oleander and seeds of syzygium jambolanum on different instars of culex quinquefasciatus and anopheles stephensi was estimated. petroleum ether (pe): ethyl acetate (ea) 3:1 fraction of v. negundo, 1:1 fractions of n. oleander and s. jambolanum inflicted considerable larval mortality and interfered with pupal-adult metamorphosis. at very low concentration the active fractions of these plant extracts extended the ...19958549835
noninfectious sporozoites in the salivary glands of a minimally susceptible anopheline mosquito.in studies to evaluate vector-malaria parasite relationships, we have found that anopheles albimanus is minimally susceptible to the rodent malaria parasite plasmodium yoelii. normally, less than 10% of a. albimanus develop oocyst infections compared to 80-100% for anopheles stephensi and anopheles freeborni mosquitoes. although sporozoites produced in a. albimanus invade the salivary glands, they are not infectious to balb/c or icr mice. in 11 experiments with sporozoites from a. albimanus, int ...19958544063
pyrethroid-sprayed tents for malaria control: an entomological evaluation in pakistan.field trials were undertaken in the north west frontier province of pakistan to determine the effects of pyrethroid-sprayed tents on feeding success, mortality and biting-rates of wild mosquitoes attracted to bait cows confined within the tents. under natural conditions, endophagic mosquitoes rested only briefly in untreated tents during the night, followed by complete exodus at dawn. in tents sprayed on the interior surface with permethrin 0.5 mg/m2 or with deltamethrin 0.03 g/m2 the biting rat ...19958541582
cloning and expression of a novel toxin gene from bacillus thuringiensis subsp. jegathesan encoding a highly mosquitocidal protein.a gene, designated cry11b, encoding a 81,293-da crystal protein of bacillus thuringiensis subsp. jegathesan was cloned by using a gene-specific oligonucleotide probe. the sequence of the cry11b protein, as deduced from the sequence of the cry11b gene, contains large regions of similarity with the cry11a toxin (previously cryivd) from b. thuringiensis subsp. israelensis. the cry11b protein was immunologically related to both cry11a and cry4a proteins. the cry11b gene was expressed in a nontoxic s ...19958534090
urban malaria and its vectors anopheles stephensi and anopheles culicifacies (diptera : culicidae) in gurgaon, india.the seasonal variation in the density of immature and adult malaria vectors anopheles stephensi and an. culicifacies were recorded from january to december, 1986 in urban gurgaon, india. the highest combined anopheline larval density (2.3 per dip) was recorded in the 31st week. the peak adult density for malaria vectors an. stephensi (4.14 per man hour) and an. culicifacies (1.02 per man hour) were reported in the month of august. the highest percentage of total infestation for anophelines and o ...19958525407
larvicidal and chemosterilant activity of annona squamosa alkaloids against anopheles stephensi.alkaloids isolated from annona squamosa have shown larvicidal growth-regulating and chemosterilant activities against anopheles stephensi at concentrations of 50 to 200 ppm. adults exposed as larvae to different treatments showed reduced fecundity and fertility in females. mortality in the larvae, pupae and adults produced about a 52-92% decrease in the laboratory experiment. the total developmental period was slightly reduced from the control. treatment with the alkaloids had a significant effe ...19938468579
experimental infection of anopheles gambiae s.s., anopheles freeborni and anopheles stephensi with plasmodium malariae and plasmodium brasilianum.susceptibility to infection of 2 strains of anopheles gambiae s.s., an. freeborni and an. stephensi, was determined for 2 closely related malaria parasites, plasmodium malariae and p. brasilianum. neither strain of an. gambiae supported development of oocyst densities as great as the other 2 anopheline mosquitoes. the zan strain of an. gambiae s.s. from zanzibar was more susceptible to infection with the strain of p. malariae from uganda than the g-3 strain of an. gambiae s.s. from the gambia. a ...19938468576
plasmodium falciparum: stage-specific ribosomal rna as a potential target for monitoring parasite development in anopheles stephensi.the transcriptional switch of plasmodium falciparum ribosomal rna a gene to the c gene was demonstrated during the developmental transition from the vertebrate blood stage to the invertebrate sporozoite stage. expression of the sporozoite specific c gene in infected mosquitoes was not detected until day 10 postinfectious blood meal, the time of mature oocyst formation on the midgut. as a potential target for monitoring malaria parasite development in mosquitoes, oligonucleotide probes based on s ...19938467898
the role of reactive nitrogen intermediates in modulation of gametocyte infectivity of rodent malaria parasites.direct feeding of anopheles stephensi mosquitoes on mice infected with plasmodium vinckei petteri showed that, during the periods of schizogony in the blood, the infectivity of gametocytes was markedly reduced. this could be prevented by prior injection of the l-arginine analogue, nw-nitro-l-arginine (nwnla) showing that the altered infectivity was due to reactive nitrogen intermediates (rni). similar effects on transmission of p. yoelii nigeriensis were demonstrated in vitro by membrane feeding ...19938433851
laboratory and field evaluation of spherix, a formulation of bacillus sphaericus (b-101), to control breeding of anopheles stephensi and culex quinquefasciatus.spherix, a powder formulation of bacillus sphaericus strain b-101, serotype h5a 5b, was evaluated against larvae of anopheles stephensi and culex quinquefasciatus in both the laboratory and field. in laboratory tests the formulation @ 0.1 g/sq m produced 100% mortality against larvae of both mosquito species at room temperature (28-32 degrees c). the larvicidal activity of spherix against an. stephensi @ 0.5 g/sq m persisted for over 12 weeks under laboratory conditions. field evaluation of sphe ...19938405598
insecticide susceptibility status of anopheles stephensi, culex quinquefasciatus and aedes aegypti in panaji, goa.adult and larval insecticidal tests conducted in panaji, goa, revealed that adults of an. stephensi were resistant to ddt (4.0%), dieldrin (0.4%) and malathion (5.0%). the larvae of an. stephensi were also resistant to ddt (2.5 mg/l) and malathion (3.125 mg/l). cx. quinquefasciatus adults were resistant to ddt, dieldrin, malathion and fenitrothion (1.0%), and larvae were highly resistant to ddt but showed low resistance to malathion and fenitrothion (0.125 mg/i). adults of ae. aegypti were resis ...19938405597
resting sites of anopheles stephensi liston in calcutta. 19938405593
kinetics of expression of two major plasmodium berghei antigens in the mosquito vector, anopheles stephensi.expression of a 21 kda determinant (pbs21), first detected on the surface of ookinetes, and of the circumsporozoite protein (csp) was studied by immunofluorescence and western blots during the developmental cycle of plasmodium berghei in the mosquito anopheles stephensi. the expression of pbs21 was predominantly localised on the ookinete surface one day after the infectious blood meal, and thereafter reactivity declined to a minimum on days 2 and 3, the time of onset of oocyst development. a gra ...19938401470
atpase activity in the midgut of the mosquito, anopheles stephensi: biochemical characterisation of ouabain-sensitive and ouabain-insensitive activities.na+/k(+)-atpase activity was demonstrated in the midgut of anopheles stephensi. more than 80% of the total atpase activity was sensitive to inhibition by ouabain with an ic50 of 4.5 x 10(-7) +/- 0.3 x 10(-7) mol l-1 and with maximal inhibition occurring at 10(-4) mol l-1. this ouabain-sensitive na+/k(+)-atpase was maximally activated at a mg2+:atp ratio of 1:1.3, with a km of 0.3 mmol l-1 and a vmax of 2.4 mumol pi mg-1 protein min-1 for atp. maximal activation was reached at 15 mmol l-1 k+ with ...19938382729
plasmodium falciparum: inhibition of sporogonic development in anopheles stephensi by gram-negative bacteria.we investigated the effects of bacteria on plasmodium falciparum sporogonic development in anopheles stephensi. four gram-negative (escherichia coli h243, e. coli hb101, pseudomonas aeruginosa, and ewingella americana) and two gram-positive (staphylococcus aureus and staphylococcus epidermidis) bacterial strains were used in the study. tenfold dilutions of bacteria suspended in phosphate-buffered saline were mixed with an infectious meal of gametocyte-enriched cultures and fed to adult mosquitoe ...19938375488
effects of ingested human anti-sporozoite sera on plasmodium falciparum sporogony in anopheles stephensi.we investigated the effects of human anti-sporozoite antibodies on the sporogonic development of plasmodium falciparum in anopheles stephensi. equal volumes of washed human erythrocytes and human sera from 1) volunteers with protective immunity induced by immunization with irradiated p. falciparum sporozoites, 2) the same volunteers before immunization, or 3) kenyans exposed to natural sporozoite transmission, were fed to cohorts of p. falciparum-infected a. stephensi on either day 5, 8, or 11 a ...19938357079
frequency of cross-fertilization in the human malaria parasite plasmodium falciparum.two clones of the human malaria parasite plasmodium falciparum, denoted 3d7 and hb3, were grown in vitro under conditions permitting the development of gametocytes. the two clones differ in their allelic forms of two antigen genes msp1 and msp2. the alleles can be distinguished as size differences of polymerase chain reaction (pcr) amplified fragments of repetitive regions of each gene. mosquitoes (anopheles stephensi) were fed on a mixture of these gametocytes. a total of 128 oocysts was isolat ...19938355994
heterogeneity in patterns of malarial oocyst infections in the mosquito vector.oocyst prevalence and intensity have been recorded in 349 laboratory infections of anopheles stephensi with plasmodium berghei. intensity and prevalence of infection are shown to be predictably related. the structure and heterogeneity in the infections has been analysed with the objective of describing the biological mechanisms by which the observed negative binomial oocyst distributions are generated. the analysis has revealed that the most likely processes lie within the population dynamic eve ...19938341579
expression of alpha-glycerophosphate dehydrogenase during the development and aging of malaria vector anopheles stephensi (diptera: culicidae).alpha-glycerophosphate dehydrogenase (gpdh) expression during the complete development and aging of anopheles stephensi has been studied by electrophoretic and spectrophotometric techniques. single gene locus seems to govern the developmental expression of three isozymes numbered from gpdh-1 to gpdh-3 in order of decreasing mobility. gpdh-3 was present in all the stages of development. gpdh-1 disappeared during senescence. gpdh-2, the band of intermediate mobility, was adult specific. gpdh-1 has ...19938309277
plasmodium berghei: serum-mediated inhibition of infectivity of infected mice to anopheles stephensi mosquitoes.the transmission of plasmodium berghei-infected mice to anopheles stephensi mosquitoes showed a peak number of oocysts early in the infection prior to the peak of gametocytaemia. this was followed by a precipitous decline on days 4 and 5 (see also dearsley et al., parasitology, 100, 359-368, 1990). by measuring percentage relative infectivity (using membrane feeds with viable gametocytes), we have shown that serum collected daily during the course of a blood-induced infection blocked infectivity ...19948299757
role of the cryivd polypeptide in the overall toxicity of bacillus thuringiensis subsp. israelensis.the gene encoding the cryivd protein of b. thuringiensis subsp. israelensis crystals was disrupted by in vivo recombination. the toxicity of the cryivd protein-free inclusions was similar to that of the wild-type crystals on anopheles stephensi larvae but was half the wild-type toxicity on culex pipiens and aedes aegypti larvae.19938285695
inhibition of malaria parasite development in mosquitoes by anti-mosquito-midgut antibodies.the mosquito midgut plays a central role in the development and subsequent transmission of malaria parasites. using a rodent malaria parasite, plasmodium berghei, and the mosquito vector anopheles stephensi, we investigated the effect of anti-mosquito-midgut antibodies on the development of malaria parasites in the mosquito. in agreement with previous studies, we found that mosquitoes that ingested antimidgut antibodies along with infectious parasites had significantly fewer oocysts than mosquit ...19948262645
cuticular hydrocarbon discrimination/variation among strains of the mosquito, anopheles (cellia) stephensi liston.cuticular lipids were removed from adult female anopheles stephensi liston and the hydrocarbons present were separated and quantified by gas chromatography. comparison was made between the hydrocarbons of four an. stephensi strains: russ, sensitive to ddt and malathion and originally isolated in the former u.s.s.r.; beech, a ddt-resistant indian strain with high sensitivity to plasmodium species; st mal, a strain from pakistan shown to be resistant to malathion; and iraq, a ddt-susceptible strai ...19938257238
inheritance and linkage of malic enzyme in anopheles stephensi.genetics and linkage analysis of malic enzyme (me) have been worked out in anopheles stephensi. genetic analysis revealed the 2 variants to be codominant alleles at a locus me, which is sex-linked. linkage studies with another x-linked mutant red-eye (r), indicated that the map distance between 2 loci was 44.60 +/- 1.07.19938245941
the effect of transmission-blocking antibody ingested in primary and secondary bloodfeeds, upon the development of plasmodium berghei in the mosquito vector.the effects of purified monoclonal immunoglobulins from control, or transmission-blocking anti-pbs21 antibodies, upon the infection of anopheles stephensi by ookinetes of plasmodium berghei are compared. anti-pbs21 antibody reduced mean intensity and prevalence of infection by 94.7 and 58.7% respectively if added to the infectious bloodfeed at a concentration of 100 micrograms/ml. fab fragments were of similar efficacy. no transmission enhancement was detected with declining antibody concentrati ...19938233585
prevention of sporogony of plasmodium falciparum and p. berghei in anopheles stephensi mosquitoes by transmission-blocking antimalarials.the sporontocidal activity of three 8-aminoquinolines, a 1,4-naphthoquinone, and three dihydroacridine-diones was determined against the anka clone of plasmodium berghei and both chloroquine-sensitive (nf54) and chloroquine-resistant (7g8) p. falciparum. anopheles stephensi mosquitoes previously fed on p. berghei--infected mice or p. falciparum--infected cultures were refed on uninfected mice treated previously with a given drug. sporontocidal activity was determined by assessing both oocyst and ...19948203716
effect of the developmental stage at infection on the ability of adult anopheles stephensi to transmit rift valley fever virus.the ability of adult anopheles stephensi to transmit rift valley fever virus was determined for mosquitoes inoculated at selected times during development. none of 109 female an. stephensi inoculated as adults transmitted virus to hamsters. in contrast, 83% (50 of 60) of those inoculated as larvae transmitted virus by bite to hamsters. transmission rates decreased as the stage of the mosquito at the time of inoculation changed from larva to pupa to adult. transmission rates for adult mosquitoes ...19948166351
studies on the immunogenicity of a recombinant ookinete surface antigen pbs21 from plasmodium berghei expressed in escherichia coli.plasmodium berghei ookinete surface antigen (pbs21), was produced as a fusion product with maltose binding protein (mbp) in escherichia coli and used to induce transmission-blocking immunity in mice. specificity of induced antibody was confirmed by western blotting with native ookinete pbs21, and by the indirect immunofluorescent antibody test on ookinete bloodfilms. immunized mice were infected with p. berghei and transmission to anopheles stephensi mosquitoes determined by both the intensity a ...19948152832
effect of pyrimethamine resistance on sporogony in a plasmodium berghei/anopheles stephensi model.a pyrimethamine-resistant line of plasmodium berghei was derived by treating infected mice with high doses of pyrimethamine and selecting for recrudescence. this resistant line was compared with the parental pyrimethamine-sensitive line in order to ascertain whether drug resistance is associated with a biological advantage. overall, the pyrimethamine-resistant line is quite similar to the sensitive line, except that it proceeds through sporogonic development more slowly than the pyrimethamine-se ...19948119374
effect of temperature on toxicity of two bioinsecticides spherix (bacillus sphaericus) and bactoculicide (bacillus thuringiensis) against larvae of four vector mosquitoes.two bioinsecticide preparations, viz. spherix (bacillus sphaericus) and bactoculicide (bacillus thuringiensis h-14), were tested in the laboratory against larvae of anopheles culicifacies, anopheles stephensi, culex quinquefasciatus and aedes aegypti at different temperatures. the lcs50 of spherix against iii instar larvae of these species at 27 +/- 2 degrees c were 2.0, 0.19, 0.05 and > 40 mg/litre, respectively and those of bactoculicide were 0.32, 0.16, 0.06 and 0.03 mg/litre, respectively. t ...19938100540
patterns of erythrocyte digestion by bloodsucking insects: constraints on vector competence.two general patterns of erythrocyte digestion were observed in representative species from four insect orders. ingested erythrocytes were hemolyzed rapidly, and blood meals remained liquefied within body lice, pediculus humanus l. and the fleas ctenocephalides felis (bouché) and xenopyslla cheopis (rothschild). peritrophic membrane was absent. in contrast, there was a lag time of 6-18 h before substantial degradation of erythrocytes within the blood meals of bed bugs, cimex lectularius l.; the s ...19938094460
filaria vector competence of some anopheles species.the filaria vector competence of anopheles stephensi was compared with brugia-susceptible aedes aegypti liverpool strain, an. gambiae badagry lagos strain and an. dirus perlis malaysia strain. an. stephensi ingested more brugia pahangi microfilariae, had the highest infectivity rate and yielded more infective mosquitoes than the other two anopheline species. the overall vector competence of an. stephensi was 0.13 times that of ae. aegypti, 0.62 times that of an. gambiae and 2.17 times that of an ...19948066378
further studies on the sporozoite transmission of the salvador i strain of plasmodium vivax.different species of saimiri and aotus monkeys were inoculated with sporozoites of the salvador i strain of plasmodium vivax. of 58 saimiri inoculated, 45 developed parasitemia (4 following bites and 41 following intravenous inoculation). prepatent periods ranged from 10 to 63 days. twelve of 19 monkeys inoculated with sporozoites that had been stored frozen developed patent parasitemia after 16-53 days. of 41 aotus monkeys inoculated, only 10 (2 via bites and 8 via intravenous inoculation) deve ...19948064516
effect of ambrosia maritima on anopheles stephensi and aedes aegypti.the toxicity of the molluscicidal plant ambrosia maritima l. was evaluated against anopheles stephensi and aedes aegypti. in the larvicidal assays a negligible mortality was observed in both species after application of the dried leaves in the water at concentrations up to 2000 mg/l. when the powdered leaves were applied at the surface of the water, however, up to 38% of the larvae of a. stephensi were killed at 2000 mg/l. virtually no inhibitory effect on the larval growth of both species was n ...19948046947
an entomological investigation of the likely impact of cattle ownership on malaria in an afghan refugee camp in the north west frontier province of pakistan.field trials were undertaken to determine the effect of close proximity of humans to livestock on the human biting rates exhibited by various anophelines. the results indicate that proximity to cattle and to goats increases the subject's chances of being bitten by anophelines. man-biting by anopheles stephensi rose by 38% (8-68% ci) in the presence of a cow, and by 50% (16-84% ci) in the presence of two goats. other species exhibited similar trends. these findings explain the results of an earli ...19948025324
inhibitory action of the anti-malarial compound atovaquone (566c80) against plasmodium berghei anka in the mosquito, anopheles stephensi.the activity of atovaquone against plasmodium berghei anka during sporogonic development has been examined. anopheles stephensi mosquitoes were fed on gametocyte infected mice which had been treated 8 h previously with atovaquone or diluent alone. mosquito midguts were examined for oocysts, and salivary gland infections were estimated using an elisa for the circumsporozoite protein (csp). the number of oocysts per midgut fell by at least 97% when mosquitoes were fed on mice dosed with 0.1-10 mg ...19948008451
evaluation of organophosphorus and synthetic pyrethroid insecticides against six vector mosquitoe species.three organophosphorus compounds- malathion, folithion and temephos- and two synthetic pyrethroids- alphamethrin and deltamethrin- were used for monitoring the susceptibility status of larvae and adults of six vector mosquito species: culex quinquefasciatus (filariasis) and aedes albopictus (dengue) (both laboratory and field strains); laboratory strains of aedes aegypti (dengue), anopheles stephensi and anopheles culicifacies (malaria), and culex tritaeniorhynchus (japanese encephalitis) in ind ...19937997809
phytotoxicological evaluation of tagetes erectes on aquatic stages of anopheles stephensi.petroleum ether (5%) in ethyl acetate fraction of tagetes erectes showed toxic activity against second and fourth instar larvae of anopheles stephensi below 100 ppm concentrations. the lc50 values for second and fourth instar larvae were calculated to be 43 and 58 ppm respectively. the second instar larvae were more susceptible than the fourth instar larvae. the extract did not affect the larval developmental period. the growth index of treated mosquitoes was significant in comparison with that ...19947958125
[in vitro cultivation of the exoerythrocytic stage of plasmodium vivax (southern china isolate)].an in vitro culture system for the exoerythrocytic (ee) stage of plasmodium vivax was first developed in our laboratory in china. anopheles stephensi mosquitoes were infected by membrane feeding with heparinized blood from a volunteer. after 14-18 days, the mosquito salivary glands were aseptically dissected in culture medium and ground in a tissue grinder to form sporozoite suspension. sporozoites were counted and added to the cultures of monolayer hepatoma cells at the number of 4.9 x 10(4)-1. ...19947955169
[plasmodium yoeli 265 by--new possibilities in the study of the resting stages of the malarial parasites].when swiss mice were experimentally infected with p. yoelii yoelii 264 by sporozoites through bites of the mosquito anopheles stephensi, there were no blood parasites in most (85%) animals after a short (on day 4-5) incubation period. the hepatic parenchymal cells from the animals without primary infection manifestation (following 2 months of the infection) or with the disease self-arrested (on day 26 of postinfection) were the first to display 5-11-microunits mononuclear parasites that are like ...19947935186
effects of para-aminobenzoic acid, insulin, and gentamicin on plasmodium falciparum development in anopheline mosquitoes (diptera: culicidae).anopheles gambiae giles sensu lato (s.l.) and an. stephensi liston were exposed as adults to para-aminobenzoic acid (paba), human insulin, or gentamicin sulfate, an antimicrobial solution, to determine their effects on plasmodium falciparum welch development to the oocyst stage. for both mosquito species, concentrations of paba from 0.001 to 0.05% had no effect on either oocyst infection rates or oocyst densities. at higher concentrations, paba-fed mosquitoes had decreased oocyst infection rates ...19947932602
efficacy of clostridium bifermentans serovar malaysia on target and nontarget organisms.clostridium bifermentans serovar malaysia (c.b.m.) is highly toxic to mosquito larvae. in this study, the following aquatic nontarget invertebrates were treated with high c.b.m. concentrations (up to 1,600-fold the toxic concentration for anopheles stephensi) to study their susceptibility towards the bacterial toxin: planorbis planorbis (pulmonata); asellus aquaticus (isopoda); daphnia pulex (cladocera); cloeon dipterum (ephemeroptera); plea leachi (heteroptera); and eristalis sp., chaoborus cry ...19947912261
time to death from starvation and compulsive killing by the larvae of toxorhynchites splendens (diptera: culicidae).time to death from starvation and compulsive killing without eating of the prey by larvae of toxorhynchites splendens were studied in the laboratory. the first and second instars survived without food for 3 days while third and fourth instars survived for 7.8 and 14 days, respectively. when the corresponding instars of aedes aegypti, anopheles stephensi or culex quinquefasciatus were offered, the number of prey killed but not eaten ranged from 0 to 15 per 40 prey larvae. compulsive killing of ae ...19947887340
toxicity of extracts from three tagetes against adults and larvae of yellow fever mosquito and anopheles stephensi (diptera: culicidae).whole-plant soxhlet extractions for the three tagetes species showed that t. minuta had the greatest biocidal effect on the larvae and adults of aedes aegypti (l.) and anopheles stephensi liston. bioassays of simultaneous steam distillation extractions of the various parts of t. minuta found extracts from the flowers provided ld90s of 4 and 8 ppm against the larvae and 0.4 and 0.45% against the adults of a. aegypti and a. stephensi, respectively. further research on t. minuta floral extracts as ...19947815394
[research on the factors influencing the sporogonic multiplication of plasmodium vivax in the mosquito vector].volunteers with no previous malaria history infected with northern guangdong isolate of plasmodium vivax and mosquito vector, anopheles stephensi, were the objects and materials used in the research. totally there were 16 volunteers, half of them were infected by mosquito-bite and another half by blood-inoculation. blood was drawn when parasitemia reached a certain level and the erythrocytic forms developed into large trophozoites. mosquitoes fed on infected blood from 5 and 4 donors of the two ...19957788889
malaria-induced reduction of fecundity during the first gonotrophic cycle of anopheles stephensi mosquitoes.anopheles stephensi mosquitoes which had fed upon mice infected with plasmodium yoelii nigeriensis malaria parasites produced significantly fewer eggs than mosquitoes fed on an uninfected mouse. fecundity reduction was more pronounced when the bloodmeal contained malaria gametocytes and the mosquitoes developed oocysts. egg production and haematin excretion were correlated for uninfected bloodfed mosquitoes; the presence of p.y.nigeriensis in the blood affected this relationship. reduced fecundi ...19957787226
inhibitory activity of the anti-malarial atovaquone (566c80) against ookinetes, oocysts, and sporozoites of plasmodium berghei.ookinete formation from mature plasmodium berghei gametocytes in vitro was partially inhibited by 0.05-0.1 microm atovaquone and almost totally blocked at a concentration of 0.25 microm. microgametocyte exflagellation was not affected by atovaquone at concentrations up to 300 microm. ookinete formation was also inhibited in culture when addition of 0.20 microm atovaquone was delayed by 4 hr, by which time dna replication was likely to have been completed. inhibition of ookinete formation by atov ...19957776134
plasmodium vivax: freeze-fracture studies on the ultrastructure of the sporozoites within the salivary gland of the mosquito anopheles stephensi.freeze-fracturing has been used to study the ultrastructure of the sporozoites of the malarial parasite plasmodium vivax within the salivary gland of the mosquito anopheles stephensi. the architecture of the pellicular complex of the salivary gland sporozoites was essentially the same as that reported for the intraoocystic forms, but the outline of cross-fractured p. vivax sporozoites was more flattened and crescent shaped as opposed to the circular outline described for the intraoocystic sporoz ...19957771612
malaria control utilizing bacillus sphaericus against anopheles stephensi in panaji, goa.in a large malaria endemic area in panaji city, goa, india, the weekly application of the biolarvicide bacillus sphaericus (strain 101, serotype h 5a 5b) at the rate of 1 g/m2 in the main anopheles stephensi larval habitats, viz., curing waters, masonry tanks, and sump tanks (under construction), from april to december 1993 resulted in a sharp decline in the habitat positivity (range 0.13-8.0%) as compared with the rest of the panaji (range 2.2-30.6%) where temephos (abate) was used as the larvi ...19947707060
electrophysiological responses of receptor neurons in mosquito maxillary palp sensilla to carbon dioxide.sensilla basiconica on the maxillary palps of female aedes aegypti contain a receptor neuron which produces a phasic-tonic pattern of action potential response to low concentrations (150-300 ppm) of carbon dioxide (co2), a stimulus known to be involved with host seeking behavior. these receptor neurons respond reliably to small increments in co2 concentration (e.g., 50 ppm). we were particularly interested in evaluating the possibility that the sensitivity to step increases in co2 concentration ...19957674195
brown larva: an allele of the green larva mutation in the malaria mosquito, anopheles stephensi.we isolated a new larval color mutant, brown larva (b), from the bangalore, india strain of anopheles stephensi liston. the gene b is an autosomal recessive with uniform expression and complete penetrance. we conducted extensive crosses to establish allelism between brown larva (b) and green larva (g) reported previously in an. stephensi from our laboratory. the wild-type is dominant to green larva, which, in turn, is dominant to brown larva. these larval color mutants belong to an allelic serie ...20067657999
murine complement reduces infectivity of plasmodium yoelii to mosquitoes.the alternative pathway of complement in the mouse serum significantly reduced, but did not eliminate, the infectivity of plasmodium yoelii to anopheles stephensi. the reduction of the infectivity is mainly due to the inability of the zygote to transform into the ookinete in the mosquito midgut.19957642309
cloning, sequencing and functional expression of an acetylcholinesterase gene from the yellow fever mosquito aedes aegypti.a degenerate pcr strategy was used to isolate a fragment of the acetylcholinesterase gene (ace) homolog from aedes aegypti and screen for a cdna clone containing the complete open reading frame of the gene. the predicted amino acid sequence of the aedes gene shares 64% identity with ace from drosophila and 87% identity with the acetylcholinesterase gene from another mosquito species anopheles stephensi. high levels of expression of the aedes gene were achieved by infection of sf21 cells with a r ...19957635199
plasmodium berghei: selection of mefloquine-resistant parasites through drug pressure in mosquitoes.mefloquine is an antimalarial drug with schizonticidal activity on blood-stage parasites. studies of the role of mefloquine on the development of plasmodium berghei anka in anopheles stephensi have been carried out that showed a dose-dependent effect on the sporogonic cycle of these parasites, with changes in the numbers of oocysts and the extent of sporozoite invasion of salivary glands. in this study, we show that mefloquine-resistant p. berghei anka blood stage parasites could be selected thr ...19957628567
cyclophosphamide: review of its mutagenicity for an assessment of potential germ cell risks.cyclophosphamide (cp) is used to treat a wide range of neoplastic diseases as well as some non-malignant ones such as rheumatoid arthritis. it is also used as an immunosuppressive agent prior to organ transplantation. cp is, however, a known carcinogen in humans and produces secondary tumors. there is little absorption either orally or intravenously and 10% of the drug is excreted unchanged. cp is activated by hepatic mixed function oxidases and metabolites are delivered to neoplastic cells via ...19957623863
depletion of total salivary gland protein in blood-fed anopheles mosquitoes.reduction in total salivary gland protein from four anopheline vectors of human malaria, anopheles stephensi liston, an. albimanus wiedmann, an. gambiae giles, and an. freeborni aitken, was quantified after mosquitoes blood-fed to repletion on human volunteers, hamsters or through a baudruche artificial membrane. total salivary gland protein from pools of six unfed mosquitoes ranged from 4.33 to 7.91 micrograms/ml. the difference between the total protein of glands from unfed and blood-fed mosqu ...19957616520
control of anopheles stephensi breeding in construction sites and abandoned overhead tanks with bacillus thuringiensis var. israelensis.bacillus thuringiensis (h-14), strain 164 (bactoculicide) when applied at 1 g/m2 surface area successfully controlled anopheles stephensi breeding in construction sites, abandoned overhead tanks, and curing waters. subsequent to application, no pupal production was observed in these habitats for 3, 18, and 21 days, respectively. based on these findings, inclusion of bactoculicide in the bioenvironmental vector control strategy is suggested and fortnightly spraying in construction sites at 1 g/m2 ...19957616196
an immunological factor that affects anopheles gambiae survival.high titers of antibodies against anopheles gambiae midguts were produced in new zealand rabbits to identify midgut targets for an antimosquito vaccine. the serum from one of 8 rabbits (designated r2b6) killed 71.6% (abbott's adjusted % mortality) of an. gambiae within 7 days. mosquitoes ingesting r2b6 serum were unable to absorb their blood meal nutrients, resulting in reduced oviposition and egg hatching rates. anopheles stephensi and anopheles arabiensis were also killed when ingesting r2b6 s ...19957616189
insect repellent formulations of n,n-diethyl-m-toluamide (deet) in a liposphere system: efficacy and skin uptake.novel formulations for a deet in liposphere microdispersion in the form of lotion were prepared from natural solid triglycerides and phospholipids dispersed in buffer solution. the formulations containing 6.5, 10, and 20% deet were effective as a repellent against the common aggressive biting mosquitoes, aedes aegypti and anopheles stephensi, for up to 6 h. the acute dermal absorption of the 10% loaded formulation was conducted in rabbits using 14c-labeled deet. 14c-labeled deet, 10% in alcohol ...19957616186
laboratory evaluation of a new repellent camouflage face paint.a combined formulation of the u.s. army's camouflage face paints and the new extended duration topical insect/arthropod repellent was tested on human volunteers to determine repellency and duration of protection (2-12 h) against aedes aegypti and anopheles stephensi. under laboratory conditions (27 degrees c and 80% rh), the face paint/repellent formulation provided > or = 95% repellency or better for up to 6 h for ae. aegypti and 8 h for an. stephensi. an analysis of variance showed no signific ...19957595441
efficacy of two flowable formulations of bacillus sphaericus against larvae of mosquitoes.laboratory evaluation revealed that the spherimos and vectolex formulations of bacillus sphaericus produced 97 and 100% larval mortality respectively in culex quinquefasciatus at a dose as low as 0.008 ml/sq m as against 93 and 97% mortality respectively at 1 ml/sq m in anopheles stephensi. however, in an. culicifacies similar level of mortality was not observed even at 10 ml/sq m of these formulations. field evaluation revealed 100% reduction of cx. quinquefasciatus larvae for 2-3 weeks in pool ...19957589732
control of mosquito breeding using wood scrapings treated with neem oil.wood scrapings were given shape of a ball and soaked in 5, 10 and 20% neem (azadirachta indica) oil diluted in acetone. control of anopheles stephensi and aedes aegypti breeding in water storage overhead tanks (ohts) with the application of these balls was achieved for 45 days. two balls soaked in 5% neem oil produced the best results among other concentrations tested.19957589730
bacillus thuringiensis serovar higo (flagellar serotype 44), a new serogroup with a larvicidal activity preferential for the anopheline mosquito.eight strains of bacillus thuringiensis, isolated in japan, formed spherical parasporal inclusions and exhibited low to moderate larvicidal activities for two mosquito species, anopheles stephensi and culex pipiens molestus, but not for another dipteran, telmatoscopus albipunctatus, or two lepidopterans, bombyx mori and hyphantria cunea. the anopheline toxicity (lc50 = 6.3 micrograms ml-1) was > 10 times greater than the activity on the culex mosquito. these strains were assigned to a previously ...19957576527
interactions between parasites and insects vectors.this review stresses the importance of studies that will provide a basic understanding of the pathology of parasite-infected vector insects. this knowledge should be a vital component of the very focussed initiatives currently being funded in the areas of vector control. vector fecundity reduction is discussed as an example of such pathology. underlying mechanisms are being investigated in a model system, hymenolepis diminuta-infected tenebrio molitor and in onchocerca-infected blackflies and pl ...19947565125
plasmodium gallinaceum: mosquito peritrophic matrix and the parasite-vector compatibility.transmission of malaria parasites occurs by relatively few species of mosquitoes. one proposed mechanism of refractoriness is an inability of certain plasmodium spp. to cross the peritrophic matrix (pm) in the midgut of an incompatible mosquito. we have tested this hypothesis by studying sporogonic development of plasmodium gallinaceum in susceptible (aedes aegypti and anopheles gambiae g3) and refractory (anopheles stephensi) mosquito species in the presence and absence of the pm. in the presen ...19957498435
safety, immunogenicity, and pilot efficacy of plasmodium falciparum sporozoite and asexual blood-stage combination vaccine in swiss adults.this study was part of a larger program to develop a vaccine effective against plasmodium falciparum infection caused by sporozoites and clinical malaria caused by asexual blood stages. in a phase 1 study of safety and immunogenicity, two recombinant proteins (ro 46-2717, a circumsporozoite [cs] protein) construct with a molecular mass of 35 kd, and ro 46-2924, a merozoite surface antigen [msa-2] construct with a molecular mass of 25 kd) adsorbed onto alum were injected in two low (20 micrograms ...19957485698
fine structure of the antennal sensory hairs in female anopheles stephensi.the fine structure of the sensory hairs on the antennal flagellum of female anopheles stephensi was studied by electron microscopy. the antennal hairs were divided into at least five different types, on the basis of hair diameter, hair wall thickness, communicating channel density, and dendritic branching in the hair lumen. regardless of different types, however, all hairs, presumed to be olfactory receptors, were found to be innervated by two sensory cells.19807376695
antennal sensory receptors of the male mosquito, anopheles stephensi.it was shown by electron microscopy that antennae of male anopheles stephensi have the same types of sensory receptors as the females, with sunken pegs (sensilla ampullacea and sensilla coeloconica), surface pegs (sensilla basiconica), hairs (sensilla trichodea), bristles and fibrillae (sensilla chaetica), and scolopidia in the johnston's organ. compared with the female, the male mosquito has fewer than half of the sensory cells in the flagellum, but many more in the johnston's organ. the smalle ...19807368776
contact and vapour toxicity of bendiocarb and pirimiphosmethyl against culex quinquefasciatus and anopheles stephensi. 19817319575
evaluation of methoprene (a juvenile hormone) against culex quinquefasciatus, anopheles stephensi and aedes aegypti. 19817309181
dna replication in polytene chromosomes: similarity of termination patterns in somatic and germ-line derived polytene chromosomes of anopheles stephensi liston (diptera: culicidae). 19817297250
studies of density and natural survival of immatures of anopheles stephensi liston in wells of salem (tamil nadu). 19817287088
the genetics of three larval mutants in anopheles stephensi. 19817287087
control of anopheles stephensi with larvicide and adulticide in salem, tamil nadu. 19817287086
[studies on antimalarial drug. ii. the causal prophylactic activity of antimalarial in animal model. part i. plasmodium yoelii-anopheles stephensi system (author's transl)]. 19817257809
inversion(2)r1 in anopheles stephensi, its distribution and relation to egg size. 19817197258
homologous banding patterns in the polytene chromosomes from the larval salivary glands and ovarian nurse cells of anopheles stephensi liston (culicidae).a comparison of the banding patterns of two homologous polytene chromosome arms from the larval salivary gland and ovarian nurse cell complement of anopheles stephensi is presented. the homologous chromosomes from the somatic larval salivary glands and germ-line derived ovarian nurse cells have essentially the same band-interband organisation. an analysis of the 3h-uridine labelling patterns of a small chromosome segment from the two tissues indicates that germ-line polytene chromosomes are not ...19817196828
satellite dna of anopheles stephensi liston (diptera: culicidae). chromosomal location and under-replication in polytene nuclei.four satellite dnas in the anopheles stephensi genome have been defined on the basis of their banding properties in hoechst 33258-cscl density gradients. two of these satellites, satellites i and ii, are visible on neutral cscl density gradients as a light density peak forming approximately 15% of total cellular dna. hoechst-cscl density gradient profiles of dna extracted from polytene tissues indicates that these satellites are underreplicated in larval salivary gland cells and adult female mal ...19817196314
a kinetic and ultrastructural comparison of alphavirus infection of cultured mosquito and vertebrate cells.vero cells and aedes pseudoscutellaris cells showed rapid production of semliki forest virus (sfv) whereas in aedes aegypti and anopheles stephensi cells no rapid production of sfv was observed. ultrastructurally the only virally induced cell inclusion in early infection was the cytopathic vacuole type 1. later in infection, in mosquito cells, electron-dense bodies appear and budding of new virions appears to be very efficient. in vero cells large accumulations of envelope proteins and nucleocap ...19827154145
linkage group iii in the malaria vector, anopheles stephensi.the linkage relationships among four loci in linkage group iii of anopheles stephensi liston have been investigated. the data indicate that the sequence is sp-dp-bl-dl, and the observed recombination frequencies are as follows: sp-dp = 35.88 percent, dp-bl = 19.48 percent, bl-dl = 21.77 percent, and sp-dl = 77.13 percent.20107153498
anopheles stephensi (diptera: culicidae): changes in male mating competence and reproductive system morphology associated with aging and mating. 19827143380
susceptibility of culex quinquefasciatus, aedes aegypti, anopheles culicifacies and anopheles stephensi against insecticides. 19827106890
electrophoretic studies on protein changes during developmental stages of anopheles stephensi. 19827085030
vaccination to prevent transmission of plasmodium yoelii malaria.it was possible to block the transmission of infection of the rodent malaria parasite plasmodium yoelii nigeriensis to anopheles stephensi mosquitoes by immunizing mice with a vaccine containing formalin-fixed gametes. both intramuscular and intravenous routes were effective, immunity was achieved with a single dose and the immunity persisted for 6 months at least. transmission-blocking immunity was found to reside in a serum factor, probably antibody, and to be directed against extracellular ga ...19827070834
the production of mature gametocytes of plasmodium falciparum in continuous cultures of different isolates infective to mosquitoes.in vitro gametocytogenesis of plasmodium falciparum was observed in all 22 isolates established in this laboratory. gametocytes were produced in variable numbers--up to 3% of red cells--for a limited period of time after which this stage was seen only very sporadically. complete maturation of microgametocytes in vitro was obtained in all 14 of the isolates that were tested for exflagellation. up to 88.2% of membrane-fed anopheles stephensi were infected from material produced in culture. it was ...19827048650
imported filariasis in pakistan.night blood surveys for filariasis were carried out in two camps of repatriates from bangladesh. the sample consisted of 1,101 biharis above one year of age of whom 9.0% were found infected with wuchereria bancrofti. the infection rate was significantly higher in males (10.2%) than in females (6.7%). of the three mosquito species (anopheles stephensi, culex pipiens fatigans and c. tritaeniorhynchus) collected in and around the camps, 4.1 and 2.5% of c. p. fatigans were found positive for w. banc ...19817036440
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