Insecticide resistance and detoxifying enzyme activity in the principal bancroftian filariasis vector, Culex quinquefasciatus, in northeastern India
| Autor: | Aparajita Borkotoki, Ravi B. Srivastava, Indra Kumar Bhattacharyya, Bipul Rabha, Diganta Goswami, Manas Sarkar, Indra Baruah |
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| Rok vydání: | 2009 |
| Předmět: |
Insecticides
Pesticide resistance Filariasis Toxicology Insecticide Resistance chemistry.chemical_compound Elephantiasis Filarial parasitic diseases medicine Helminths Animals Humans Ecology Evolution Behavior and Systematics General Veterinary biology Dose-Response Relationship Drug biology.organism_classification medicine.disease Culex quinquefasciatus Enzyme assay Insect Vectors Culex Deltamethrin chemistry Insecticide resistance Insect Science Vector (epidemiology) biology.protein Parasitology Female |
| Zdroj: | Medical and veterinary entomology. 23(2) |
| ISSN: | 1365-2915 |
| Popis: | The insecticide resistance status of Culex quinquefasciatus Say (Diptera: Culicidae) to DDT and deltamethrin across army cantonments and neighbouring villages in northeastern India was investigated. In India, DDT is still the insecticide of choice for public health programmes. In military stations, pyrethroids, especially deltamethrins, are used for insecticide-treated nets (ITNs). Recent information on the levels of resistance to DDT and deltamethrin in mosquito populations of northeastern India is scare. Continued monitoring of insecticide resistance status, identification of the underlying mechanisms of resistance in local mosquito populations and the establishment of a baseline data bank of this information are of prime importance. Insecticide susceptibility assays were performed on wild-caught adult female Cx. quinquefasciatus mosquitoes to the discriminating doses recommended by the World Health Organisation (WHO) to DDT (4%) and deltamethrin (0.05%). Across all study sites, mortality as a result of DDT varied from 11.9 to 50.0%, as compared with 91.2% in the susceptible laboratory strain (S-Lab), indicating that Cx. quinquefasciatus is resistant to DDT. The species was found to be 100% susceptible to deltamethrin in all study sites except Benganajuli and Rikamari. Knock-down times (KDT) in response to deltamethrin varied significantly between study sites (P < 0.01) from 8.3 to 17.8 min for KDT(50) and 37.4 to 69.5 min for KDT(90). All populations exceeded the threshold level of alpha-esterase, beta-esterase and glutathion S-transferase (GST) established for the S-Lab susceptible strain, and all populations had 100% elevated esterase and GST activity, except Missamari and Solmara. Beta-esterase activity in Field Unit II (96.9%) was less than in any of the other populations. Benganajuli had the highest activity level for all the enzymes tested. There was a significant correlation between all enzyme activity levels and insecticide resistance phenotype by populations (P < 0.05). The results presented here provide the first report and baseline information of the insecticide resistance status of Cx. quinquefasciatus in northeastern India, and associated information about biochemical mechanisms that are essential for monitoring the development of insecticide resistance in the area. |
| Databáze: | OpenAIRE |
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