PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Mosquito Control”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 721 records · Page 40Linked to original sources
PubMed1993

Control of Mansonia mosquitos, vectors of brugian filariasis in Sarawak, Malaysia.

Two field trials in the control of subperiodic brugian filariasis vectors, mainly Mansonia bonneae and Mansonia dives were carried out in Sarawak, East Malaysia. In the first trial, malathion ultra-low volume (ULV) spray was used to control the Mansonia mosquitos in two filariasis endemic villages. Six spray rounds were applied at biweekly intervals at Kampung Rasau and two spray rounds were applied at monthly intervals in Kampung Triboh. ULV malathion spray reduced biting Ma. bonneae population for 3 days after spraying. The biting density decreased to 50% of the pre-treatment level by the 12th - 13th day and reached the pre-treatment level by the 24th - 25th day. Contact bioassay tests on caged Mansonia mosquitos revealed considerable penetration of the malathion aerosol indoors and relatively adequate coverage outdoors. The estimated number of bites per case per day was 1.09 to 4 times less in the sprayed kampung than in an unsprayed control kampung. The parous and daily survival rates of Mansonia mosquitos were not significantly affected by the spraying. In a second trial, chemotherapy with diethylcarbamazine citrate (DEC) was combined with vector control through indoor residual spraying in Kampung Ampungan. The results were compared with the use of only DEC mass treatment in Kampung Sebangkoi and Kampung Sebamban. The combined control measures in Kampung Ampungan reduced the MfD-50 to 44% of the pre-treatment level over a period of 4 years. In the other two kampungs where only mass DEC therapy was applied, the microfilarial rate and MfD-50 declined significantly in the second blood survey but increased gradually in two subsequent follow-up blood surveys. The total insecticidal impact for Ma. bonneae was 3.9 to 1 indoors and 2.7 to 1 outdoors. These results indicated that quarterly pirimiphos-methyl indoor spraying used in integrated control could reduce indoor transmission by 3.9 times. The infective rate from the Ma. bonneae dissected in all three kampungs after the interventions, irrespective of DEC treatment alone or in combination with pirimiphos-methyl residual spraying were reduced by two fold. However the infection rate of brugian filarial larvae in Kampung Ampungan was significantly reduced after the use of DEC and insecticide. Annual Transmission Potential (ATP) showed a high significant reduction in Kampung Ampungan (p > 0.001) compared with Kampungs Sebangkoi and Schambam. In Ampungan, the ATP was reduced by 8.5 times indoors after the MDA and insecticidal application and 3 times outdoors. The reduction rate for Sebangkoi and Sebamban both indoors and outdoors were less than 2 fold.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2004

Observations on anopheline breeding in relation to aquatic plants in different breeding habitats of Kheda (Gujarat).

Water bodies infested with aquatic vegetations may pose problems in mosquito control through bio-environmental methods. Paucity of information pertaining to association of mosquito breeding with aquatic vegetation was the basis for present investigation. The mosquito breeding sites infested with solitary/dominating plant community viz., Eichhornia crassipes, Ipomoea aquatica, Hydrilla verticillata, Nymphea neuchali, Trapa bispinosa, Lemna paucicostata, Trachelomonas spp., Azolla pinnata, Algae spp. and Cynodon dactylon were selected for the study. The investigation revealed that breeding of eleven anopheline species was associated with Eichhornia in different habitats followed by Hydrilla, algae and Cynodon (8 each), Ipomoea and Trapa (6), Lemna. and Nymphea (5), Azolla and Trachelomonas (4). An. subpictus was associated with all types of vegetation. An. annularis, An. nigerrimus and An. barbirostris were associated with nine plant species. An. culicifacies, the principal malaria vector was found breeding in association with seven aquatic plants and showed strong association with Cynodon, Hydrilla and algae. The species diversity in habitats infested with Hydrilla, algae and Cynodon seems to be most favourable for the breeding of An. culicifacies. It is suggested that thinning or removal of such vegetations at regular interval may help to reduce vector population and enhance the efficacy of biological control agents particularly the larvivorous fishes in such habitats.

Animals↗
PubMed2003

Isolation of a Pseudomonas fluorescens metabolite/exotoxin active against both larvae and pupae of vector mosquitoes.

A formulation was developed from the metabolite(s) of a novel Pseudomonas fluorescens Migula strain (VCRC B426) and tested against 4th-instar larvae and pupae of three species of vector mosquitoes, Anopheles stephensi Liston, Culex quinquefasciatus Say and Aedes aegypti (L). The larvae and pupae of An. stephensi were the most susceptible to the formulation, followed by those of C. quinquefasciatus and Ae. aegypti, in that order, and the dosage requirement for pupal mortality was less than that required for larval mortality. The LC50 dosage requirements for larvae of these mosquito species were, respectively, 70.4, 511.5 and 757.3 microg protein ml(-1), whereas for pupae they were, respectively, 2.0, 9.4 and 19.2 microg protein ml(-1). The lethal fraction was purified from the culture broth and its molecular mass, as determined by high performance liquid chromatography, was 44kDa. This is the first report of a microbial formulation acting upon mosquito pupae, a non-feeding stage. Its mode of action and efficacy to control mosquitoes under field conditions need to be studied further.

Animals↗
PubMed1966

Attractant and stimulant factors for oviposition of Culex pipiens fatigans in natural breeding-sites.

The breeding of mosquito larvae in the field is determined by the ovipositing behaviour of the gravid females. Investigation of the chemical factors that induce oviposition is therefore important for understanding mosquito ecology. These substances may also prove to be useful in assessing and controlling mosquito populations.The author has demonstrated two chemical factors, an ovipositing attractant and an ovipositing stimulant, in surface-water. The ovipositing attractant, extracted from surface-water by distillation and extraction with diethyl ether, was found to be quite effective when used to recapture known numbers of gravid mosquitos released in a large calf-shed. The presence of the stimulant factor was established by forcing gravid females to touch the testing water with tarsi and proboscis. After such contact, they began oviposition three times more rapidly on surface-water than on tap-water.The importance of these factors was demonstrated in the larval populations of Culex pipiens fatigans in pit-latrines in Rangoon, Burma.

Animals↗
PubMed2004

Entomological investigations in a focus of dengue transmission in Cairns, Queensland, Australia, by using the sticky ovitraps.

Sticky ovitraps (patent pending) were used to sample female Aedes aegypti (L.) weekly in a focus of dengue activity in Cairns, Queensland, Australia. In February 2003, transmission of dengue virus serotype 2 began in the suburb of Parramatta Park, peaking in mid-March 2003. This suburb features many older, unscreened houses with high populations of Ae. aegypti. Highest densities (2-3.5 females per trap per week) were obtained during peak dengue transmission (January and February) before mosquito control was initiated. Beginning in late March, female Ae. aegypti collected in sticky ovitraps were tested for dengue viral RNA by using a TaqMan reverse transcription-polymerase chain reaction assay. Dengue viral RNA was detected in six pools of Ae. aegypti collected in late March. The highest minimum infection rate was 116/1000 mosquitoes. After the initiation of larval control (containers treated with S-methoprene or lambda-cyhalothrin) and adult control (interior harborage sites sprayed with lambda-cyhalothrin) in early March, trap collections dropped to <0.5 per trap per week, and no virus was detected in trapped mosquitoes. Human cases subsequently dropped from a high of seven cases per day in mid-March to only sporadic cases in late April, with the final reported onset of 7 May. Sticky ovitraps have potential as a monitoring device for gravid Ae. aegypti and can be used to assess control efficacy and dengue virus activity. A sticky ovitrap index (mean number of female Ae. Aegypti per trap per week) could be useful in gauging the risk of dengue transmission.

Aedes↗
PubMed2005

Non-larvicidal effects of Bacillus thuringiensis israelensis and Bacillus sphaericus on oviposition and adult mortality of Culex quinquefasciatus Say (Diptera: Culicidae).

Two microbial mosquito larvicides, Bacillus thuringiensis ssp. israelensis (Bti) and Bacillus sphaericus (Bsph), have been shown to be highly effective in controlling mosquito larvae and have been used in larvicidal programs for many years. In exploring other modes of action of these agents, we studied the ovipositional response of Bsph susceptible and resistant Culex quinquefasciatus to aqueous suspensions of Bti and Bsph water dispersible granules (WDG). We quantified the level of mortality of adult mosquitoes caused by exposure to Bti and Bsph suspensions during oviposition. Significantly lower numbers of egg rafts were laid and collected from the treatments than the control regimen. There was an inverse relationship between Bacillus product concentrations and oviposition. As the concentration of Bti or Bsph increased from 0.0 to 2.0 mg/L, treated waters received progressively fewer egg rafts. In addition to the negative effects of Bacillus on oviposition, both male and female adult mosquitoes suffered high mortality on landing and imbibing on Bti and Bsph suspensions, the extent of mortality directly proportional to concentration. These two microbial agents used solely as mosquito larvicides thus have the additional benefits of reducing mosquito oviposition and killing adult mosquitoes, especially gravid females that come in contact with the treated water either for oviposition or drinking. Reducing the number of gravid females may also result in reduced transmission rates of pathogens. The combined effects of reduced oviposition and adult mortality could result in higher control potential of these microbial agents.

Animals↗
PubMed2004

Mosquito immune responses against malaria parasites.

Anopheline mosquitoes are the major vectors of human malaria. Mosquito-parasite interactions are a critical aspect of disease transmission and a potential target for malaria control. Mosquitoes vary in their innate ability to support development of the malaria parasite, but the molecular mechanisms that determine vector competence are poorly understood. This area of research has been revolutionized by recent advances in the mosquito genome characterization and by the development of new tools for functional gene analysis.

Animals↗
PubMed1992

DDT and HCH residues in indoor air arising from their use in malaria control programmes.

Samples of air from rooms in a residential and rural environment, treated with either DDT or HCH at rates recommended for mosquito control under the National Malaria Eradication Programme of India, i.e. 2 and 3 g m-2, respectively, were analyzed for the residues of these insecticides. During the 8-month sampling period, DDT and HCH levels in indoor air ranged from 1.0 to 14.6 and 0.9 to 2000.1 micrograms m-3, respectively. After an initial fall, residues of DDT showed an increase again and were 5.9 micrograms m-3 in samples collected 240 days after the initial application. In contrast, HCH residues declined at a fast rate in a few days after application and remained low at the time of subsequent samplings. HCH residues were present chiefly in the vapour phase throughout the study. Thirty-four to seventy-eight percent of DDT residues were found in the particulate phase in the samples collected up to 64 days after its application and exclusively in the vapour phase at the time of later samplings. Apart from the contamination of food and feed commodities stored in premises treated for malaria control by absorption of insecticides present in the indoor atmosphere, the residues of these persistent compounds in air are also likely to result in low level pollution of the surrounding and distant environmental media by their dispersion in the global ecosystem.

Air Pollutants, Occupational↗
PubMed2005

Low pilot exposure to pyrethrin during ultra-low-volume (ULV) aerial insecticide application for control of adult mosquitoes.

Pilot exposure to pyrethrin was monitored after 2 aerial applications of a ultra-low-volume (ULV) pyrethrin insecticide for the control of adult mosquitoes. Pyrethrin exposure was estimated by measuring the excretion in urine of a common metabolite, trans-chrysanthemumdicarboxylic acid, of the natural pyrethrin mixture. Pyrethrin exposure estimated by total daily urine volume was well correlated (R2 = 0.8) with exposure estimated by the creatinine-adjusted volume of combined workday urine voids, indicating that a postapplication spot urine sample would be sufficient to measure pyrethrin exposure. Pilot exposure to pyrethrin was very low after both insecticide applications. The highest exposure was found on day 1, with a dose of 2.05 microg pyrethrin equivalents/day or a dosage of 0.03 microg pyrethrin equivalents/kg/day. These exposure rates represent approximately 1/2,800,000th of the low observed adverse effect level and 1/1,000th of the acceptable daily intake for pyrethrin. The aerial application of ULV pyrethrin insecticide for the control of adult mosquitoes does not result in undue exposure to a pilot who is trained and certified to conduct such control operations.

Aircraft↗
PubMed1995

Mosquito-transmitted malaria in New York City, 1993.

In August, 1993, 3 cases of Plasmodium falciparum malaria in people without recent travel histories or bloodborne exposure were reported in New York City. An epidemiological investigation confirmed the absence of risk factors for acquisition of malaria in two cases. The third case could not be definitively classified as locally acquired malaria because the patient had travelled to Thailand two years before malaria was diagnosed. The 3 individuals lived in separate houses in the same neighbourhood of Queens, New York and had onset of illness within a day of each other. The investigation consisted of patient interviews, active case finding, reviewing recent New York flight and shipping arrivals, and an entomological survey for anopheline mosquitoes and breeding sites. No other cases were identified. The 3 patients lived several miles from air and sea ports and prevailing winds would have carried any mosquitoes at those sites away from the patient's homes. By the time of the environmental investigation (September, 1993), the area was dry and neither adult nor larval anophelines were found. However, weather conditions at the probable time of infection (July, 1993) were very different. Malaria was probably transmitted to these 2 patients by local anopheline mosquitoes that had fed on infected human hosts. Mosquito-control measures were not implemented because there was no evidence of ongoing transmission. The occurrence of mosquito-transmitted malaria in New York City demonstrates the potential for reintroduction of malaria transmission into areas that are no longer endemic and emphasises the need for continued surveillance and prompt investigations, if cases without risk factors are reported.

Adult↗
PubMed1984

Collection Of Adult And Larval Mosquitoes In U.S. Army Compounds In The Republic Of Korea During 1979~1983.

This paper is the result of adult female mosquito and larval collection in U.S. Army Installations in Korea from 1979 to 1983. New Jersey light traps ere operated for ault collection from May to October. The primary concern of this surveillance is to determine when to recommend insecticide spraying for mosquito control in the Army areas. The 5th Preventive Medicine Unit have developed an "index" level of female mosquitoes in a light trap similar to other U.S.Army Agencies in other parts of the world. When 10 female mosquitoes are reached on two consecutive trap-night, or 5 known vector females are collected, fogging is recommended in the trap areas. Mosquito collections were conducted in 12 U.S. Army areas by operating 39 New Jersey light traps. Mosquitoes collected from the areas were identified to be 17 species comprising 3 genera. Anopheles sinensis(40%). Culex tritaeniorhyncus(31%), Aedes vexans nipponii(19%), and Culex pipiens pallens(10%) appeared to be the most common species in the area. The species, population density and monthly appearance of adult mosquitoes were found to be almost the same in the all provinces involved. And Japanese encephalitis vector mosquitoes, Culex tritaeniorhyncus, showed their seasonal fluctuation from July to September with a peak in August each year. 3. Larval habitats confirmed in the Army areas were categorized into 16 types as shown in Table The mosquito larvae collected in those habitats were identified to be 15 species representign 4 genera. Most breeding sites in the Army areas were those which are activated during the wet season. More mosquitoes were collected from the Kyungki province than from the other provinces. The reason for more collection of mosquitoes from military installations in the Kyungki provinces appears to be the geographic characteritics surrounded by rice fields, marshes and other stagnant water areas.

Journal Article↗
PubMed2005

Sensitivity of the larvivorous copepod species, Mesocyclops pehpeiensis and Megacyclops viridis, to the insect growth regulator, pyriproxyfen.

The effects of the insect growth regulator pyriproxyfen were evaluated on the mortality, fecundity, longevity, and predation capability of 2 species of copepods, Mesocyclops pehpeiensis Hu and Megacyclops viridis (Jurine), under laboratory conditions. Pyriproxyfen showed no significant effects on either the development or reproduction of M. pehpeiensis at 0.1 ppm, which is a 10-fold greater concentration than the reported effective dosage for controlling mosquito larvae (0.01 ppm). In contrast, the development of M. viridis was impaired by pyriproxyfen at 0.1 ppm. An 80% reduction in nauplius survivorship was observed in the experimental (treated) group compared with the control group. Although the application of pyriproxyfen caused high mortality in the nauplius stage of this species, the pyriproxyfen-treated group developed faster, killed more mosquito larvae, yielded more eggs per oviposition event, and survived longer than the control group. These results indicate that pyriproxyfen caused mortality in the earlier stages of this sensitive species but that the surviving individuals were those that were selected for significantly faster development, better predation ability, and greater longevity during their reproductive stage. Therefore, under natural conditions, pyriproxyfen would cause modifications in the characteristics of a copepod population rather than its complete loss. Our results suggest that the combined application of copepods and pyriproxyfen to control Aedes populations is feasible. However, repeated application of pyriproxyfen may cause changes in copepod populations and communities in the affected ecosystem.

Aedes↗
PubMedDate not supplied

[Data on a study of a natural focus of sandfly fever in Sevastopol during 1945-1988].

Sandfly [correction of Mosquito-borne] fever in Sevastopol was of a marked season character (June-September), with maximum cases registered in August. The morbidity curve corresponded to the sandfly [correction of mosquito] number curve, lagging behind it because of the incubation period. Since 1947 DDT and hexachlorane, having a lasting effect (40-50 days), have been widely used for sandfly [correction of mosquito] control. This was accompanied by intensive improvement of the living conditions in the city, regular sanitation and deratization. As a result of the above measures sandfly [correction of mosquito-borne] fever has not been registered in the city since 1954. The number of sandflies [correction of mosquitoes] reduced drastically, their species composition has changed: in 1959 sandflies [correction of mosquitoes] were found in 5.4% of the houses examined and in 1988, in 0.16% of houses. Since 1958 only 2 (Phlebotomus papatasii Scop and Ph. major Ann.) out of the former 7 species have been caught. Each species strives for self-preservation. Therefore, epidemiological survey of the former foci and sandfly-control [correction of antimosquito] measures are to be performed annually not to permit recovery of sandfly [correction of mosquito] population and repeated epidemics of sandfly [correction of mosquito-borne] fever.

Animals↗
PubMed2004

Effect of temperature stress on immature stages and susceptibility of Aedes aegypti mosquitoes to chikungunya virus.

A high temperature stress of 44.5 degrees C for 10 minutes on the larval stages was found to affect the susceptibility of adult Aedes aegypti mosquitoes to chikungunya virus. At this temperature, the mortality of the mosquito larvae was found to be approximately 95%, whereas a temperature greater than 45 degrees C for 10 minutes was found to be lethal. A temperature tolerant (TT) strain was developed by exposing the larvae to a temperature of 44.5 degrees C for 10 minutes at every generation for five generations. This strain was established to determine whether increase in the susceptibility was due to any selection pressure of higher temperature or to the influence of other intrinsic factors such as expression of immunoresponsive (IR) genes. Other studies on these mosquito strains showed that when maintained at 28 +/- 1 degrees C, there was no difference in the larval duration and mortality in the immature stages, but the mean survival of female mosquitoes in the TT strain was 5-6 days longer. Conversely, when mosquitoes were maintained throughout at 37 degrees C the mean survival of the mosquitoes decreased drastically in both strains, but the mean survival of females in the TT strain was 5-6 days longer compared with the unstressed controls. This increases the probability of at least one more blood meal. Fecundity of the TT strain was found to be lower than that of the control mosquitoes. Data suggest that expression of certain IR genes was affected by the heat shock. Some of these genes were up-regulated and down-regulated, which may have affected the susceptibility of mosquitoes to the virus. Although there was some selection in the temperature-tolerant individuals in the TT strain, when stressed by heat they showed expression of IR genes in a pattern similar to that in the normal controls. It appears that an increase in temperature above the average temperature of an area might help increase the proportion of virus-susceptible mosquitoes in the population. Such an increase in temperature in an endemic area would not only enhance the selection of temperature-tolerant individuals in a population having more longevity, but would also affect both intrinsic and extrinsic factors by reducing the extrinsic incubation period and increasing susceptibility of mosquitoes to viruses due to affected expression of IR genes.

Aedes↗
PubMed2003

Stable integration and expression of mosquito-larvicidal genes from Bacillus thuringiensis subsp. israelensis and Bacillus sphaericus into the chromosome of Enterobacter amnigenus: a potential breakthrough in mosquito biocontrol.

Previously, we have successfully integrated a spectinomycin/streptomycin resistance gene into Enterobacter amnigenus strain An11, a potential host for mosquito control, using in vivo recombination via homologous recombination (An11S4::Omega). We now report the successful transfer of two mosquito-larvicidal genes, cry4B from Bacillus thuringiensis subsp. israelensis and binary toxin genes from Bacillus sphaericus, into the host genome. To facilitate the screening procedure, the E. amnigenus derivative, An11S4::Omega, was used as a host. The integration of both toxin genes by two successive crossover events interrupted the Omega region yielding two integrants designated An11S4::cry4B and An11S4::Omega::bin, respectively. Differences in the integration efficiency of these toxin genes were observed. The presence of both genes in the target sites of the host genome was verified by PCR. Cry4B was expressed weakly from An11S4::cry4B, but no expression of the binary toxin gene could be detected from An11S4::Omega::bin. Nevertheless, these two integrants exhibited mosquito-larvicidal activity against Aedes and Culex, suggesting that both proteins were expressed, but at very low levels.

Animals↗