Does resistance of Anopheles mosquitoes to knock-out effect of DDT deter the ability of the chemical to control malaria in Uganda?

Abstract

The WHO/HQ, Geneva, developed general guidelines for monitoring and management of insecticide resistance. These were adapted for local conditions by the WHO/AFRO and were made available to national programs for use. The guidelines proposed strategies to prevent/delay development of resistance; approaches to minimize impact of resistance should it appear; and possible alternative strategies in case of resistance reached to a level requiring replacement of the insecticides in use. For Africa South of the Sahara, at least six organizations formed a partnership called the African Network on Vector Resistance to insecticides (ANVR).This network made sub-partnerships with national research institutions, national vector control programs and the private sector in each African country to make large-scale entomological surveys focusing on vector susceptibility to insecticides and updating vector distribution throughout the WHO African region. In Uganda, ANVR made their appropriate studies and established that the major malaria vector, Anopheles gambiae, was resistant to the vector control chemicals in use (DDT and Icon). They showed that new chemicals, the carbamates and organophosphates, were fully efficacious on the local vector and recommended immediate change to the new chemicals. Commissioned by the Ministry of Health (MoH), this work followed up the ANVR experiments in Uganda, compared the issues accrued with those on record from similar studies done in Kihihi in 1957-1960 and found that the ANVR studies were well designed and well done but the interpretation of the results only favoured their objectives.

Keywords: Insecticide, repellancy, vector, irritance, IRS, susceptibility.