Preliminary examination of integrated vector management in a tropical rainforest area of Cameroon

Abstract

In the tropical rainforest area of Cameroon, people are affected by blackflies (Simulium spp.) and mosquitoes (Anopheles spp). Use of insecticide-treated bed nets (ITNs) has been promoted to protect vulnerable groups from mosquito bites, whereas historically indoor residual spraying (IRS) was the primary intervention. In a malaria-endemic area, a pilot study examined different mosquito control interventions applied to entire villages to assess their impact on vectors, malaria incidence and the quality of life of the communities. The Sanaga River near these villages was treated with insecticide to kill blackfly larvae. A medical survey of the six villages had shown that 20% of the population suffered from malaria, while 50% were infected with onchocerciasis and 5% with Loa loa. IRS+ITN using ICON CS (lambda-cyhalothrin capsule suspension formulation) or improved screening of houses combined with outdoor misting reduced the numbers of mosquitoes collected from exit traps compared to the other treatments. More sporozoites were detected in mosquitoes sampled in exit traps in the untreated village than in the treated villages. Malaria incidence several months after treatments was not significantly different from pre-treatment levels. Blackfly adult populations were reduced for several weeks following larvicide application but recovered when treatment was halted.