Susceptibility Status of Anopheles Culicifacies against DDT 4% & Malathion 5% in Districts of Madhya Pradesh

Madhya Pradesh is the largest state in the country having an area of 308,252 sq.km. Malaria control in Madhya Pradesh is complex because of the vast tracts of forests with tribal settlements. Anopheles culicifacies is the principal malaria vector in rural and peri- urban areas and contributes about 65% of malaria cases in India. Study was carried out to know the present status of susceptibility of An. culicifacies against DDT 4% and Malathion 5% in Madhya Pradesh. Today, the issue of major concern is the development of resistance among mosquito vectors as a result of abrupt and indiscriminate use of insecticides. In the present study, insecticide susceptibility of An. culicifacies against DDT and Malathion was tested in Seoni, Katni, Umaria, Anuppur, Satna, Chhindwara, Dhindori, Narsingpur and Mandla districts. The districts selected for assessment of susceptibility have almost similar ecotype, vector prevalence and employ same vector control strategies. Susceptibility test was done as per standard WHO susceptibility tests using DDT 4% & Malathion 5%. Results indicate that An. culicifacies was found resistant to DDT in all nine districts of Madhya Pradesh viz. Seoni, Katni, Umaria, Anuppur, Satna, Chhindwara, Dhindori, Narsingpur and Mandla. An. culicifacies was found susceptible to Malathion 5% in Umaria, Anuppur, Satna, Dindori, Narsinghpur and Mandla district and resistant to it in Chhindwara district of Jabalpur zone. Development of resistance to DDT and tolerance against Malathion in Seoni and Katni districts is of great concern to vector control programme. Complete resistance to DDT can be attributed to the fact that DDT has been in use since many decades (1953). DDT has also shown resistance in areas irrespective of its withdrawal from IRS. This could be due to increased genetic stability of DDT resistance gene. Malathion was not sprayed regularly but observed resistance and tolerance could be due to selection of its use by agriculture/ forestry.