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Memórias do Instituto Oswaldo Cruz
Fundação Oswaldo Cruz, Fiocruz
ISSN: 1678-8060
EISSN: 1678-8060
Vol. 104, No. 5, 2009, pp. 673-677
Bioline Code: oc09152
Full paper language: English
Document type: Research Article
Document available free of charge

Memórias do Instituto Oswaldo Cruz, Vol. 104, No. 5, 2009, pp. 673-677

 en Development of physiological resistance and its stage specificity in Culex quinquefasciatus check for this species in other resources after selection with deltamethrin in Assam, India
Sarkar, Manas; Bhattacharyya, Indra K; Borkotoki, Aparajita; Baruah, Indra & Srivastava, Ravi B

Abstract

The study investigated the development and stage specificity of physiological resistance to insecticides in a colony of Culex quinquefasciatus check for this species in other resources Say (Diptera: Culicidae) mosquitoes, which are vectors of bancroftian filariasis in India, after selection with deltamethrin. Resistance was selected by exposing the larvae to the concentration of deltamethrin that caused 50% mortality in the tested population (i.e., LC50). Under continuous selection pressure, the LC50 increased steadily in subsequent generations. The estimated LC50 for the F0 generation was 0.409 μg/L; the LC50 first displayed a substantial increase in the F5 generation (5.616 μg/L) and reached 121.902 μg/L in the F10 generation. The objective of this study was to establish a deltamethrin-resistant colony to develop a research programme that will study the evolution of physiological resistance patterns and stage-specific resistance responses in Cx. quinquefasciatus larvae and adults under laboratory conditions. An approximately 298-fold increase in resistance was recorded after 10 generations, as evidenced by the resistance ratio (RR50). The progress and effect of the selection pressure in the adult stage was monitored with the World Health Organisation (WHO) diagnostic test. The mortality, as observed using the WHO diagnostic test, declined significantly from the F5 generation (85%) onwards and the highest rate of survival (65%) was observed in the F10 generation.

Keywords
Culex quinquefasciatus - deltamethrin - India - resistance - stage specificity - selection pressure

 
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