Insecticide Susceptibility Status ofAnopheles gambiaes.l. (Diptera : Culicidae) in the Republic of Cameroon

Abstract

A large-scale survey of Anopheles gambiae Giles, 1902 susceptibility to DDT, dieldrin, permethrin, and deltamethrin was conducted in the Republic of Cameroon. 15 field populations from various geographical areas were tested using World Health Organization test kits for adult mosquitoes. The laboratory Kisumu susceptible reference strain was tested as a control. Results showed that dieldrin and DDT resistance was still present in some populations, and indicated permethrin or deltamethrin resistance. Within the Anopheles gambiae complex, resistant individuals belonged to An. gambiae s.s. and An. arabiensis species. Both M and S molecular forms of An. gambiae s.s. were found resistant. In most of resistant populations, the knockdown times were 2-5-folds increased. However, none of the surviving mosquitoes was positive to the kdr "Leu-Phe" mutation using polymerase chain reaction (PCR) diagnostic test. These results likely suggested involvement of other resistance mechanism(s), such as enzyme detoxification or kdr "Leu-Ser" mutation. Researches on An. gambiae s.l. resistance should be promoted in Cameroon, to improve malaria vector control programs and to implement resistance management strategies.

High Level of DDT Resistance and Reduced Susceptibility to Deltamethrin in <i>Anopheles gambiae</i>, <i>Anopheles coluzzi</i>, and <i>Anopheles arabiensis</i> from Urban Communities in Oyo State, South-West Nigeria

“…Figure 1 Mortality in percentage of Anopheles mosquitoes exposed to 4% DDT and 0.05% Deltamethrin across the six localities One of the major malaria vector control intervention in Nigeria is the distribution and use of LLIN (National Malaria Strategic Plan, 2014-2020. The LLINs are impregnated with mainly pyrethroids (WHO, 2010) and the massive use of these nets have been reported to select resistant populations in Anopheles gambiae and Anopheles funestus (Etang et al, 2003;Corbel et al, 2004). The data from our study sites (80%-100% mortality) indicate that resistance to pyrethroid is ongoing in Oyo State which could be, in part, as a result of the use of LLIN.…”

Susceptibility test of female anopheles mosquitoes to ten insecticides for indoor residual spraying (IRS) baseline data collection in Northeastern Nigeria

“…The farmers in the community also use cypermethrin, lambdacyhalothrin, deltamethrin, dichlovos and primiphos-methyl for agricultural crop protection. Previous researchers have reported that exposure of malarial vectors to crop protection insecticides could result in development of insecticide resistance (Etang et al, 2003;Awolola et al, 2007;Müller et al, 2008;Chouaibou et al, 2008;Bigoga et al, 2012;Philbert et al, 2014). LLIN was used in Misau for protection against mosquitoes since 2002 to date and it may induce selections to pyrethroids insecticides.…”

Very high DDT-resistant population ofAnopheles pharoensisTheobald (Diptera: Culicidae) from Gorgora, northern Ethiopia

“…pharoensis, we observed a significant increase of these values (2-3 fold) compared to susceptible reference strain of other species such as An. gambiae (Chandre et al, 2000;Etang et al, 2003). The possible cross resistance between DDT and pyrethroids, the absence of knockdown effect of DDT, and the increase of KT for pyrethroids strongly suggested that at least a target site mutation (kdr) was involved in resistance.…”