Spatial distribution of insecticide resistance and susceptibility in Aedes aegypti and Aedes albopictus in India

Vector-borne diseases are a major burden to the human health. Vector species of Aedes mosquitoes transmit several arboviral diseases, including dengue, chikungunya, yellow fever and Zika. According to the World Health Organization, the dengue virus causes about 390 million infections per year out of which almost 96 million have manifests clinically with high severity of the disease. For vector and pest control, excessive use of insecticides is the widest option (different sectors have used 451,000 metric tonnes of some selected technical grade pesticides that have been used from 2011–19 in various sectors). Data for the present review was collected from published papers from 1993 to 2019 from journal websites, google scholar, research gate. Dichlorodiphenyltrichloroethane (DDT) has been used since 1946 in malaria and pest control and results in widespread resistance in both vector species: Aedes aegypti and Aedes albopictus in almost all states of India. Aedes aegypti shows a high degree of resistance to permethrin, lambda-cyhalothrin, and cyfluthrin, while Aedes albopictus is still susceptible to these insecticides in most areas across the country. Enhanced activity of detoxifying enzymes such as cytochrome P450, glutathione-S-transferase, esterase, gamma-aminobutyric acid, and mixed-function oxidase was reported in resistant populations as compared to susceptible populations. Based on the review, we conclude that prolonged exposure to insecticides has led to the development of resistance against organochlorines, organophosphates, pyrethroids, and carbamates. Mixed and synchronized activities of these detoxifying enzymes are related to the development of resistance. As such, minimal and rotational use of insecticides can prevent the development of resistance in mosquitoes.