Assessment of Insecticide Resistance Monitoring Practices for Malaria Vectors in Delta State

Insecticide resistance in Anopheles mosquito populations is a growing threat to malaria vector control programme effectiveness in Nigeria, and regular resistance monitoring is essential for evidence-based insecticide selection. This study assessed the current practices and capacity for insecticide resistance monitoring of malaria vectors in Delta State, South South Nigeria. A facility capacity assessment was conducted at the State Ministry of Health entomology unit and three research partner institutions. Structured interviews with entomologists and insectary managers assessed monitoring frequency, WHO tube bioassay capacity, molecular resistance marker testing capability, and data utilisation for programme decision-making. Physical inspection assessed insectary infrastructure, rearing colony status, and availability of standard WHO testing kits. Only one of four assessed institutions maintained a functional Anopheles insectary for resistance monitoring. WHO tube bioassays were conducted in the preceding 12 months by only one facility, documenting resistance to pyrethroids and DDT. Molecular kdr resistance genotyping was not performed at any state-level institution. Resistance monitoring data had not been formally utilised in insecticide procurement decisions within the preceding three years. The study recommends strengthening state entomological capacity through infrastructure investment and integration of resistance data into annual programme planning cycles in Delta State. Keywords: insecticide resistance, Anopheles, resistance monitoring, Delta State, vector control.