Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CULEX”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 307 records · Page 17Linked to original sources
PubMed1987

Laboratory and field efficacy of Bacillus thuringiensis var. Israelensis and Bacillus sphaericus against Anopheles gambiae s.l. and Culex quinquefasciatus in Ouagadougou, Burkina Faso.

Two wettable powders (Bactimos and Vectobac) and one flowable concentrate (Teknar) of Bacillus thuringiensis var. israelensis (B.t.i.) and primary powders of Bacillus sphaericus isolates 1593 and 2362 were evaluated (laboratory) against field-collected larvae of Anopheles gambiae s.l. and Culex quinquefasciatus in Ouagadougou, Burkina Faso. Bactimos, Vectobac and a Corn-cob B.t.i. formulation (ABG-6138G) were field tested against Cx. quinquefasciatus and An. gambiae s.l. The isolates of B. sphaericus were also tested against An. gambiae s.l. in artificial ponds. Both wettable powders of B.t.i. showed superior activity than the flowable concentrate formulation against An. gambiae s.l. in the laboratory. Culex quinquefasciatus was more susceptible (3-4X) to B.t.i. (Bactimos) than An. gambiae s.l. The isolates of B. sphaericus were more effective (2-3X) against both mosquito species than Bactimos. In a ditch and two channels, Bactimos, Vectobac and ABG-6138G at 0.65, 1.5 and 5.6 kg/ha, respectively, gave 91-100% control of Cx. quinquefasciatus within 3 days of treatment. The same formulations at rates ranging from 0.25 to 5.6 kg/ha, produced 82-97% control of An. gambiae s.l. in rainwater pools 24 h after treatment. Isolates 1593 and 2362 at 0.12 and 0.24 kg/ha gave excellent control of An. gambiae s.l. in artificial ponds.

Animals↗
PubMed1987

Temperature and water quality effects in simulated woodland pools on the infection of Culex mosquito larvae by Lagenidium giganteum (Oomycetes: Lagenidiales) in North Carolina.

Asexual stages of the California (CA) isolate of Lagenidium giganteum cultured on sunflower seed extract (SFE)-agar, were applied to outdoor pools containing Culex larvae near Raleigh, NC in August and September 1984. Infection rates among the larvae ranged from 19 to 74% at 2-4 days posttreatment and subsequent epizootics eliminated most of the newly hatched larvae for at least 10 days posttreatment. Substantial reductions in numbers of larvae and adult emergence were achieved from a single application of the fungus. Water quality and temperature data are presented. From laboratory assays of organically polluted water, the percent infection of Culex quinquefasciatus by the fungus was correlated with water quality and temperature. A logistic model of water quality (COD and NH3-N) effects on infectivity rates by the CA isolate is described.

Animals↗
PubMed1987

Genetic association between highly active esterases and organophosphate resistance in Culex tarsalis.

The genetics of two highly active esterases, A3H and B3H, in a methyl parathion-resistant strain (MP-R) of Culex tarsalis was investigated in relation to organophosphate (OP) resistance. The increased activity of esterase A3 and of esterase B3 is under the control of two distinct and closely linked (approximately 4.4 centimorgans) genes. Each gene possesses two forms, one controlling high activity (A3H or B3H, respectively) and one controlling low activity (A3L or B3L, respectively) of the enzymes. Organophosphate resistance in the MP-R strain is strongly associated with the presence of these highly active esterases. The results are discussed in relation to the present knowledge on the mechanisms responsible for high activity of esterases observed in other OP-resistant mosquitoes of the genus Culex.

Animals↗
PubMed1987

Efficacy of Bacillus sphaericus and Bacillus thuringiensis var. israelensis for control of Culex pipiens and floodwater Aedes larvae in Iowa.

Granular and flowable concentrate formulations of Bacillus thuringiensis var. israelensis provided a 90-100% reduction in Aedes vexans and Culex spp. larvae in natural larval habitats. A briquet formulation of B. thuringiensis was less effective, providing a 12-76% reduction. No residual activity occurred in sites treated with B. thuringiensis. Granular formulations of Bacillus sphaericus (2.78-8.42 kg/ha) caused a 100% reduction in Culex pipiens larvae in natural sites and artificial pools. Bacillus sphaericus also controlled (84-98% reduction) a mixed population of Aedes trivittatus and Cx. pipiens in subplots of a retention pond. In field sites, B. sphaericus continued to control Cx. pipiens larvae for 96 hr.

Aedes↗
PubMed1987

Effectiveness of five methods for sampling adult Culex mosquitoes in rural and urban habitats in San Bernardino County, California.

The comparative effectiveness of NJ light traps, CO2-baited traps, walk-in red boxes, high-intensity light traps and gravid traps for sampling adult Culex mosquitoes for arbovirus surveillance was compared at rural dairy and residential urban habitats near Chino, California. Culex quinquefasciatus was the most abundant of the 3 species present comprising 94.9% of the 23,159 mosquitoes collected, followed by Cx. peus (4.2%) and Cx. tarsalis (0.9%). Female mosquitoes of all species were most abundant in CO2-baited traps at both urban and rural environments. Males were collected most effectively by walk-in red boxes in rural, but not urban, environments. More parous females were collected by CO2-baited traps at urban than rural habitats; however, 70-79% of all females were nulliparous and had never blood fed. These data point out the potential insensitivity of the current sampling methodology in monitoring mosquito arbovirus infection rates.

Animals↗
PubMed1986

The salivary gland chromosomes of Culex tarsalis.

The salivary gland chromosomes of Culex tarsalis are described and briefly compared to similar descriptions of other Culex species previously published. Additional cytogenetic evidence will be needed to make meaningful comparisons and hypothesize speciation relationships.

Animals↗
PubMed1986

Studies on insecticide susceptibility of Anopheles gambiae s.1. and Culex quinquefasciatus in the area of Ouagadougou, Burkina Faso (west Africa).

Tests to evaluate the susceptibility level in Anopheles gambiae s.1. and Culex quinquefasciatus from Ouagadougou and two nearby villages have been carried out. Anopheles gambiae s.1. larvae from Ouagadougou showed complete susceptibility to organophosphates and carbamates, and adults showed low level resistance to DDT. Nine percent survival of adult An. gambiae s.1. to one hour exposure of 4% DDT was observed in samples from Zaghtouli village while in those from Koubri village, where dieldrin also was tested, resistance to both organochlorine insecticides was detected. Culex quinquefasciatus showed susceptibility to fenthion, malathion, fenitrothion, and chlorpyrifos, whereas incipient resistance to temephos was detected. Electrophoretic analysis showed polymorphism of high and low active esterases (Est-2 + Est-3) confirming the association between OP resistance and enhanced esterase activity in this species.

Animals↗
PubMed1977

[Sexual receptivity of the female and insemination power of the male Culex pipiens autogenicus (Diptera, Culicidae). The cases of strict monogamy and occasional polygamy].

Females of Culex pipiens autogenicus generally have two refractory periods: post-emergence refractory period (during the first 48 hrs. after emergence) and post-insemination refractory period. Males of Culex pipiens autogenicus can inseminate 2 to 3 females. After the 4th insemination he can no longer completely fulfill his reproductory role. Therefore the female can inseminated by another male.

Animals↗
PubMed1985

Correlation of population indices of female Culex tritaeniorhynchus with Japanese encephalitis viral activity in Kapuk, Indonesia.

Nineteen consecutive monthly light trap collections of mosquitoes were made between October 1978 and April 1980 in Kapuk, Indonesia. Kapuk is a small suburb of Jakarta where pigs are raised in close proximity to rice paddies which are breeding sites for Culex tritaeniorhynchus. Japanese encephalitis (JE) virus is believed to be endemic and has been recovered from mosquitoes and pigs in the area on several occasions. A total of 18,435 female Cx. tritaeniorhynchus were allocated to 359 pools of approximately 50 per pool. Virus isolations were attempted in both Vero and BHK-21 cells and agents producing cytopathic effect were identified in a micro-neutralization test. Nineteen strains of JE were recovered from the 359 pools of Cx. tritaeniorhynchus tested. The light trap index of female Cx. tritaeniorhynchus (X) and the relative frequency of pools positive for JE (Y) for each month of the study were plotted and correlation coefficients (r) calculated after transforming the mosquito population data logarithmically and the relative frequencies of isolation by arcsine square root. The close fit of the data (p less than 0.001) to an inverse linear model (1/y = a + b log10X) suggests a close dependence of JE viral activity on the population dynamics of Cx. tritaeniorhynchus. Three additional strains of JE were recovered from other Culex spp. at the same study site. One strain each was isolated from individual pools of Cx. gelidus, Cx. vishnui and Cx. fuscocephala. Cx. tritaeniorhynchus was more frequently infected with JE than the other species tested.

Culex↗
PubMed1973

Host-feeding patterns and behaviour of 4 Culex species in an endemic area of Japanese encephalitis.

Studies were made on the host-feeding patterns and behaviour of 4 Culex species in China (Province of Taiwan) to further assess their importance as vectors of Japanese encephalitis. A relatively unbiased, non-attractant technique (vacuum sweep-net) was used for collecting mosquitos resting outdoors on rural premises; blood meals from engorged specimens were identified by precipitin tests. Additional information was obtained by analysing data from related studies. Precipitin-test results indicated that C. annulus, C. tritaeniorhynchus, and C. fuscocephalus feed principally on mammals, the first species mainly on swine and the latter two largely on bovine hosts. Mosquito forage ratios suggested that the apparent preference of C. annulus for swine over bovine hosts might be a function of host density. C. annulus was found to be zoophilic, exophilic, and exophagic; however, in view of its abundance during the JE epidemic season, contact with human hosts may reach a significant level, even indoors. The other 3 species of Culex were considered to be of lesser importance as JE vectors during the 1971 epidemic season because of their host-feeding patterns and/or population densities.

Animals↗
PubMed1967

Genetical linkage relationships of DDT-resistance and Dieldrin-resistance in Culex pipiens fatigans Wiedemann.

The tropical house mosquito Culex fatigans readily develops resistance to DDT and to dieldrin and hexachlorocyclohexane. Studies of the mode of inheritance of these two types of resistance in material from Rangoon selected to a high resistance level showed DDT-resistance to be due to a single principal gene which was almost completely dominant and dieldrin-resistance to be due to a single gene allele neither dominant nor recessive, the hybrids being intermediate.The DDT-resistance factor was linked with the chromosome-2 marker genes y (yellow larva) and ru (ruby eye), at crossover distances of approximately 20 and 45 percentage units respectively. The dieldrin-resistance factor was linked with the chromosome-3 marker gene kps (clubbed palpi) with a crossover value between 35% and 40%. In contrast to Aedes aegypti, where these two genes are close together on chromosome 2, in Culex fatigans the dieldrin-resistance gene is separated on to chromosome 3.

Animals↗
PubMed1969

Results of fenitrothion selection of Culex pipiens fatigans Wied. and Anopheles albimanus Wied.

Laboratory selection of Culex pipiens fatigans (=C. quinquefasciatus) and Anopheles albimanus by fenitrothion pressure for 30 and 25 generations, respectively, resulted in only 2.2-fold and 1.1-fold increases in tolerance to this compound. Cross-resistance to arprocarb in Culex increased 12.2-fold but smaller increases in tolerance to fenthion, malathion, DDT, and dieldrin, may be manifestations of vigour tolerance. Since the essential conditions for selection are believed to have been fulfilled, the authors consider the negative results obtained to be of practical significance, as well as of academic interest.

Animals↗
PubMed1983

[Information on Culex torrentium and C. territans (Diptera, Cilicidae)].

Larvae of Culex torrentium were found in Leipzig in the reed of a little permanent water and in a trough of artificial stone. Data on siphonal indices and on types of breeding waters have been arranged in a table. A list with the hitherto existing breeding places in the GDR has been provided. There are altogether 11 places in 10 regions of 7 districts. Culex territans was found at 6 places in 7 regions of the district of Leipzig.

Animals↗
PubMed1983

Residual toxicity of deltamethrin and permethrin on various surfaces for mosquito species culex pipiens molestul Forskal.

The culicine mosquito species Culex pipiens molestus Forskal were exposed by tarsal contact to various surfaces sprayed with the photostable synthetic pyrethroid preparations deltamethrin (NRDC 161) and permethrin (NRDC 143) used in the form of emulsifiable concentrates (EC) and wettable powders (WP) at doses 0.001, 0.005, 0.02, 0.1 and 0.5 g/m2. The time to appearance of the knock down effect and the residual toxicity were tested for each preparation and type of surface studied. The onset of deltamethrin and permethrin knock down effects was found to be very rapid at higher insecticide doses. The mean KT 100 value for permethrin EC at 0.5 g/m2 and for deltamethrin EC and WP at 0.1 g/m2 measured within the first month after insecticide application were almost invariably below 60 min on all the surfaces tested. Taking the 2-month interval as a sufficiently long period of operationally effective residual activity, the following insecticide doses can be recommended as optimal for the Culex mosquito control inside the dwelling space: deltamethrin EC and WP doses of 0.001 g/m2 for plywood, 0.005 g/m2 for whitewashed surface, 0.02 g/m2 for ceramics, and 0.02 (WP) and 0.1 (EC) g/m2 for limewashed surface; permethrin EC doses of 0.1 g/m2 for all types of surfaces and permethrin WP doses of 0.005 g/m2 for plywood and 0.02 g/m2 for the remaining types of surfaces.

Animals↗
PubMed1981

Some aspects on biting cycles of Culex quinquefasciatus in Bangkok.

The indoor and outdoor biting cycles of Culex quinquefasciatus were studied in Bangkok. The biting cycle was nocturnally periodic and preferably endophilic in character. There were two minor peaks on top of the nocturnally periodic peak. The first peak was between 2200 and 2300 hours, the latter peak was after midnight being at 0100 and 0400 hours. Parous mosquitoes formed 0%-20.0% of hourly total population. More parous mosquitoes were collected indoor and also during in the latter half of the night. Comparisons made between Bangkok, the none endemic area for Wuchereria bancrofti and Sri Lanka the endemic area, revealed that Bangkok has a lower survival rate of Culex quinquefasciatus, based on parous rates and that the older mosquitoes, which are potentially infective vectors were collected late in the night. This evidence could explain why Bangkok is not endemic area for periodic Wuchereria bancrofti.

Animals↗
PubMedDate not supplied

[Action of some chemical products--insecticides and detergents--on the larvae of mosquitoes of Anopheles labranchiae atroparvus and Culex pipiens autogenicus species].

The larvicide effects of some insecticides and detergents on the Anopheles labranchiae atroparvus species--laboratory colonie--and Culex pipiens autogenicus species, living in flooded basements of some block-houses in the town of Slobozia, were estimated. These products were classified in some categories, depending on their effects: 1. knock-down effect products ; 2. products having a relatively strong effect ; 3. products having a slow effect ; 4. products with a slight effect. Remanence tests were performed on Culex pipiens autogenicus, which showed that Toxid and Lindatox have a longer remanence than the other substances used. In mosquito larvae field control 1 ppm pyrethrum products like Decis and Isathrine, trichlorfon products like Clorofos, Dipterex and Dimetox and organophosphorus carbetox on both species are recommended.

Animals↗
PubMed1995

[Preparation and characterization of monoclonal antibodies against esterase of malathion-resistant Culex quinquefasciatus].

Five clones of monoclonal antibodies (McAbs) were generated from BALB/c mice which were activized with PPD and immunized with esterases extracted from malathion-resistant Culex quinquefasciatus. All 5 clones of McAbs belonged to the IgG1 subtype, additive index (A.I.) of every two McAbs did not exceeded 50%. After a 1 h of incubation, the McAbs at the titer of 1:1,000 completely inhibited the activity of the amplified esterases. Of 8 strains of adult mosquitoes studied by Western-blot assay, all exhibited the 64 kDa esterase band recognized by the McAbs, six (SP, FS, SH, CD, RD, RM) showed more bands of different MW (43-60 kDa), the higher the organophosphorus resistant level, the more and the denser the bands. The above McAbs had little or no effect against the esterases of dimethrin-resistant strain and the larva stage of malathion-resistant Culex quinquefasciatus.

Animals↗
PubMed1993

[A biochemical method for the determination of the altered acetylcholinesterase which confers resistance to organophosphate and carbamate insecticides in Culex quinquefasciatus Say, 1823].

The application of a rapid technique to determine the frequency of the altered acetylcholinesterase gene which confers cross resistance to organophosphate and carbamate insecticides to mosquitoes, was tested. Laboratory strains of Culex quinquefasciatus Say, 1823 were used to apply this technique: A clear differentiation in absorbance values was attained among resistant susceptible homozygous mosquitoes (SS), heterozygous (RS); and homozygous (RR), with residual enzymatic activity values of 10-60; 70-100; and 80-120, respectively. This was clearly differentiated at first sight due to a change of the reaction's yellow color. The gene of the altered acetylcholinesterase was found in the Culex quinquefasciatus strains under study.

Acetylcholinesterase↗