Vol. 12, Issue 6, Part A (2025)

Author(s): Akash Chowdhury, Shampa Dutta, Joyanta Karmakar, Madhusudan Das, Ardhendu Kumar Maji and Pabitra Saha

Abstract: Informations about insecticide susceptibility status among malaria vectors is helpful for detecting emerging resistance trends, selecting appropriate insecticides and evaluate the impact of vector control interventions. Present study assessed the insecticide susceptibility status of Anopheles culicifacies and Anopheles stephensi against DDT, deltamethin, malathion and alpha-cypermethrin across five districts of northern West Bengal using WHO bioassay protocol and kit. Both species showed high resistance to DDT, with corrected mortality (CM) rates below 79%. Against pyrethroids, An. culicifacies populations from Darjeeling, Uttar Dinajpur, and Malda and An. stephensi from Darjeeling and Malda exhibited probable resistance, suggesting emerging tolerance trends. In contrast, malathion remained largely effective in most areas. The spatial variation in resistance levels reflects differing ecological conditions and insecticide exposure histories. Persistent DDT resistance and rising pyrethroid tolerance highlight the need for regular monitoring, insecticide rotation, and integrated vector management strategies to sustain malaria control and support India’s malaria elimination program.

DOI: 10.22271/23487941.2025.v12.i6a.866