Dynamics of insecticide resistance in Anopheles arabiensis and Culex pipiens complex, and its associations to agricultural practices in southern Tanzania

Vector control is a principal component of all malaria control strategies in sub-Saharan Africa. It relies primarily on two major interventions including long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS). However, the effectiveness of these interventions is partly compromised by an increased geographical spread of insecticide resistance in the targeted mosquito populations. The use of agricultural pesticides may enhance selection pressure and increase resistance in mosquitoes, but the current vector control practices do not consider the intensive pesticides use in agriculture as a factor in the spread of resistance and most of the farming activities are not incorporated in malaria control programs.

The main aim of this thesis was to investigate the dynamics of insecticide resistance in the malaria vector, Anopheles arabiensis and Culex pipiens complex, and its associations to agricultural practices, in areas where LLINs have been the primary malaria intervention strategy but where malaria transmission still persists in rural southern Tanzania. The study examined the spatial temporal variations in phenotypic resistance and its mechanisms in the malaria vector, An. arabiensis, and the nuisance-biting mosquitoes, Culex pipiens complex in southern Tanzania. It then explored types of agricultural pesticides as well as the knowledge, views and practices linked to resistance development, among farmers, pesticide dealers and policy advisors. Lastly, it explored opportunities to engage and improve farmers’ awareness of insecticide resistance in malaria vectors and relationships to agricultural pesticide use practices. The major policy implication of the study findings is the need for harmonized strategies between the public health and agricultural sectors in vector and pest management and strengthening insecticide resistance surveillance for sustainable vector control.