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 523 records · Page 29Linked to original sources
PubMed1997

Culicidae (Diptera) in the diet of predatory stages of anurans (Amphibia) in humid biotopes of the Rhine Valley in Germany.

A three-year field study was conducted during 1993 to 1995 to determine the importance of mosquitoes in the diet of anurans. The study was aimed to assess the impact of biological mosquito control on the populations of amphibia in the Rhine Valley, Germany. Sampling took place in two areas with stands of different deciduous trees at the western bank of the Rhine (north of Karlsruhe, Germany) from early May to late October. The frequency and species composition of the terrestrial stages of Amphibia was monitored by hand catches and by live pitfall trapping. A total of 2,419 Amphibia were caught in the three years. Of these, 95.8% were anurans, consisting of 77% Ranidae, with 25.5% Rana arvalis, and 4.2% were Urodela, Salamandridae. All anura caught were subjected to "stomach flushing" to yield their stomach contents before they were released again. The stomachs of 2,163 anuran specimens contained an average of 7.7 prey items, of which only 0.16% were Culicidae. In R. arvalis the total diet consisted of 33% Collembola, spiders and beetles; 0.1% of the specimens in the diet were Culicidae. The most common culicid species in the study area, Aedes vexans, was also most often found in the anuran stomachs. However, no correlation existed between the number of mosquitoes and their number as prey of Anura. It is concluded that anurans will not be negatively affected by biological mosquito control in the Rhine Valley. Furthermore, the impact of anurans on Culicidae seems to be negligible.

Aedes↗
PubMedDate not supplied

Biochemical, immunological and toxicological characteristics of the crystal proteins of Bacillus thuringiensis subsp. medellin.

Characterization of the insecticidal and hemolytic activity of solubilized crystal proteins of Bacillus thuringiensis (Bt) subsp. medellin (Btmed) was performed and compared to solubilized crystal proteins of isolates 1884 of B. thuringiensis subsp. israelensis (Bti) and isolate PG-14 of B. thuringiensis subsp. morrisoni (Btm). In general, at acid pH values solubilization of the Bt crystalline parasporal inclusions (CPI) was lower than at alkaline pH. The larvicidal activity demonstrated by the CPI of Btmed indicated that optimal solubilization of CPI takes place at a pH value of 11.3, in Bti at pH values from 5.03 to 11.3 and in Btm at pH values from 9.05 to 11.3 Hemolytic activity against sheep red blood cells was mainly found following extraction at pH 11.3 in all Bt strains tested. Polyacrylamide gel electrophoresis under denaturing conditions revealed that optimal solubilization of the CPI in all Bt strains takes place at the alkaline pH values from 9.05 to 11.3. An enriched preparation of Btmed crystals was obtained, solubilized and crystal proteins were separated on a size exclusion column (Sephacryl S-200). Three main protein peaks were observed on the chromatogram. The first peak had two main proteins that migrate between 90 to 100 kDa. These proteins are apparently not common to other Bt strains isolated to date. The second and third peaks obtained from the size exclusion column yielded polypeptides of 68 and 28-30 kDa, respectively. Each peak independently, showed toxicity against 1st instar Culex quinquefasciatus larvae. Interestingly, combinations of the fractions corresponding to the 68 and 30 kDa protein showed an increased toxicity. These results suggest that the 94 kDa protein is an important component of the Btmed toxins with the highest potency to kill mosquito larvae. When crystal proteins of Bti were probed with antisera raised independently against the three main protein fractions of Btmed, the only crystal protein that showed cross reaction was the 28 kDa protein. These data suggest that Btmed could be an alternative bacterium for mosquito control programs in case mosquito larval resistance emerges to Bti toxic proteins.

Animals↗
PubMed1998

Impact of Spherix (Bacillus sphaericus B-101, serotype H5a, 5b) spraying on the control of mosquito breeding in rural areas of Farrukhabad District, Uttar Pradesh.

Spray impact of Spherix (Bacillus sphaericus B-101, Serotype H5a, 5b) was assessed against larval and adult populations of mosquito species in rural areas of Farrukhabad district, Uttar Pradesh. High mortality (> 95%) was observed against anopheline and culicine larvae within 48 h of spray @ 1 g/sq m. But the biolarvicidal effect declined within a week which indicated nonrecycling capacity and weekly reapplications were required. The encouraging results obtained through weekly sprays were short-lived because of decline in efficacy in some perennial intradomestic Culex breedings after 15 rounds of spray. The two year intensive field trials, however, had no appreciable impact on adult densities of both malaria vector An. culicifacies and bancroftian filariasis vector Culex quinquefasciatus. Environmental disturbances and manmade problems also affected the efficacy of the biolarvicide.

Animals↗
PubMed1999

Effects of ultra-low volume pyrethrin, malathion, and permethrin on nontarget invertebrates, sentinel mosquitoes, and mosquitofish in seasonally impounded wetlands.

Wildlife managers are concerned that insecticides used to control mosquitoes could suppress invertebrates on which wildlife feed. We assessed whether ultra-low volume (ULV) applications of pyrethrin, permethrin, and malathion for control of adult mosquitoes reduced macroinvertebrate abundance and biomass or killed mosquitofish in seasonal wetlands in California. Pyrethrin was applied over 3 seasonal wetlands on Sutter National Wildlife Refuge (NWR), and malathion or permethrin were each applied over 2 seasonal wetlands on the Colusa NWR. Three control wetlands were used per site. We measured aquatic macroinvertebrate abundance and biomass before and after insecticide application and compared the survival of mosquito larvae held in sentinel cages. At Colusa, we also used mosquitofish as sentinels, caged adult mosquitoes over the wetlands to test for pesticide efficacy and drift, and sampled night-flying insects using ultraviolet light traps. Results showed no detectable reductions in the abundance or biomass of aquatic macroinvertebrates in treated wetlands. Larval mosquitoes showed high survival in all areas. All adult mosquitoes died when caged over wetlands treated with malathion or permethrin, but all survived in controls. All mosquitofish survived. Flying insect abundance decreased after insecticide application in both treated and control wetlands but rebounded in 48 h. Results indicated that ULV applications of these insecticides to control adult mosquitoes are unlikely to have substantial effects on the aquatic insects or fish in seasonal wetlands.

Animals↗
PubMedDate not supplied

[Current epidemiological malaria situation in Kyrgyzstan (1995-1999)].

Kyzgyzstan is situated in an area which is potentially at risk for malaria. In 1995-1999, 58 cases of malaria were recorded, six of them were local cases. The factors that promote the spread of malaria in Kyrgyzstan are the widespread and constant migration of people from Tajikistan and close economic ties between Kyrgyzstan and a number of Asian countries with widespread malaria epidemics. Most cases of malaria in Kyrgyzstan were imported from Tajikistan (39 cases or 75% of all imported cases). Plasmodium vivax, P. falciparum and P. malariae were identified in 95.9, 1.7, and 2.1%, respectively. There is a widespread irrigation network in the country, along with a large number of reservoirs, ponds, lakes, springs, streams, gullies, and marshy floodplains. As of 1 January 2000, there are 2833 water areas that can support Anopheles mosquitoes, with a total area of 5008.5 ha. The total length of the sewerage and drainage system is 5,440 km. There is a great potential for the spread of malaria in the south of the republic, i.e. the Osh and Zhalalabad Regions, especially due to a large number of state rice (paddy) fields covering an area of over 3,500 ha. Small rice-growing plots close to private dwellings, which are cultivated without any mosquito control measures, currently provide further breeding grounds for mosquitoes. Almost 80% of the population of these areas is at risk for malaria. Almost all species of malaria mosquitoes have been identified in Kyrgyzstan. An. claviger and An. messeae have too, two other species have also spread through the country, these are An. martinius and An. superpictus which became the main vectors of malaria epidemics in the south in the 1930s-1950s. Large-scale development of the pre-imago stages of the mosquito (a larval, water-based stage) takes place 5-7 months within which 4-6 mosquito generations develop. At present, there is a shortage of staff in Kyrgyzstan, especially at a local level, who has thorough knowledge of malaria and experience with its control and who can define the highest priorities and the most appropriate and effective within the Global Malaria Control Strategy at the current stage. Laboratory services are in need of considerable support: stocks of essential supplies for laboratory tests are almost exhausted, there is a shortage of essential equipment, the staff is not well enough trained. There is an acute shortage of insecticides and larvicides for mosquito control. Entomologists have no sufficient insect control equipment to treat water areas (e.g. sprayers), there is no equipment for monitoring water areas or introducing larvicidal fishlaria (Gambusiae) either, and local monitoring is hampered by shortages of vehicles, fuel, and lubricants. Since malaria control is an urgent problem, Kyrgyzstan has developed a comprehensive and integrated malaria programme for 2000-2004 and a plan of actions to study malaria vector resistance to insecticides in the Republic of Kyrgyzstan in 2000.

Humans↗
PubMedDate not supplied

[Utilization of the waste of sisal industry in the control of mosquito larvae].

The aim of this research was to utilize the waste residues of sisal fiber separation from Agave sisalana leaves to develop a larvicide for the combat of mosquito transmitting tropical diseases. Larvae of Aedes aegypti and Culex quinquefasciatus were exposed to different concentrations of the Agave extract for 24 hours to determine lethal concentrations. The LC50 for A. aegypti was 322 ppm and the LC50 for C. quinquefasciatus was 183 ppm. To detect the active substances, saponins were investigated. It was found that the various components of the extract were effective in eliminating the larvae. Under field conditions, this formulation can probably be used at 100 ppm, which causes 100% mortality of C. quinquefasciatus larvae after 3-4 days. The product is not recommended for use against A. aegypti due to the necessity for high concentrations and to the fact that the larvae of this species live frequently on drinking water. To avoid fermentation, Agave extract should be used in a dehydrated form which also represent a good formulation for practical use.

Aedes↗
PubMed1956

Radioisotopes for research on and control of mosquitos.

Practical applications of radioactive isotopes in medicine, science, and industry have multiplied enormously during the past five years. In this paper, the author attempts to gather what is known about the use of radioactive isotopes in the research on malaria control.The development of the uranium pile for large-scale production of radioisotopes and technical progress in the making of reliable electronic equipment have greatly contributed to the application of radioactive tracers in biological research. The present knowledge of radioisotopes in mosquito and in insecticide research is discussed.

Animals↗