Susceptibility of Anopheles gambiae s.l. to DDT, malathion, permethrin and deltamethrin in Ethiopia

Abstract

Summaryobjective To assess the susceptibility ⁄ resistance level of Anopheles gambiae s.l. to DDT, malathion, permethrin and deltamethrin in different parts of Ethiopia.methods Field collected female An.gambiae s.l. was exposed for 1 h to discriminating dosage of 4% DDT, 5% malathion, 0.75% permethrin and 0.05% deltamethrin using WHO insecticide susceptibility test kits and procedures. Knockdown and mortality rates were recorded at 10, 15, 20, 30, 40, 50 and 60 min and 24 h post-exposure respectively.results Anopheles gambiae s.l. was sensitive to DDT only in 2 of 16 localities where susceptibility studies were carried out in northern Ethiopia; it was resistant in 11 sites and potentially resistant in three. To malathion, the test population was sensitive in four of the six study sites in southern Ethiopia and potentially resistant in the other two sites. In northern Ethiopia, the population was resistant in five localities and sensitive in three. Of the six localities in northern Ethiopia where permethrin was tested, populations were sensitive in three, resistant in one and potentially resistant in two. In southern Ethiopia, the populations were resistant in five of the six sites. Against deltamethrin, the population was sensitive in five of 13 localities, three in northern and two in southern Ethiopia. It was resistant only in two localities, one in northern and one in southern Ethiopia, and potentially resistant in five localities. In eastern Ethiopia at Sabure, the population was sensitive to all insecticides but DDT to which it was potentially resistant. conclusion The existence of high level of DDT and pyrethroid resistance with the possibility of crossresistance to each other and other classes of agricultural pesticides could seriously jeopardise the efficacy of both ITNs and IRS in the country in the future. Insecticide resistance monitoring and surveillance systems as part of a malaria control programme are mandatory for proper management of resistance. The use of a mixture of unrelated insecticides for impregnating nets and rotational use of insecticides for IRS is suggested as a way forward.

Insecticide Resistance inAnopheles arabiensisfrom Ethiopia

“…However, the FMOH shifted from using DDT to deltamethrin in the 2009 spray programme due to high DDT resistance in An. arabiensis populations (FMOH Report 2010; Abate & Hadis 2011). The shift to deltamethrin is on an interim basis until a suitable alternative insecticide is chosen.…”

In vitro studies of larvicidal effects of some plant extracts against Anopheles gambiae larvae (Diptera: Culicidae)

“…According to the studies conducted in Ethiopia (Abate and Hadis, 2011) Anopheles arabiensis was resistant to an array of insecticides, including DDT, permethrin, deltamethrin and Malathion. Similarly World Health Organization (WHO, 1992) has documented mosquito resistance to the aforementioned four classes of insecticides.…”

Repellent Effects of Aloe pirottae (Aloaceae) Gel Extract and Brassica nigra (Brassicaceae) Essential Oil against the Malaria Vector, Anopheles arabiensis Patton (Diptera: Culicidae)

“…Resistance to insecticides is a serious problem of malaria control efforts in all regions where insecticides are used to kill mosquitoes. Anopheles arabiensis are the most important malaria vector in Ethiopia, which is strongly resistant to DDT and pyrethroids [5][6][7].…”