The Role of Entomological Monitoring for Malaria Vector Control Aklilu Seyoum July 2015

Introduction AIRS has been Implementing IRS in multiple African countries in collaborating with NMCPs and partners Understanding and monitoring the species composition of malaria vectors, behavior and insecticide resistance status are critical for the program success IRS operations and Entomological Monitoring in 15 sub-saharan African countries Benin, Ethiopia, Ghana, Madagascar, Mali, Mozambique, Rwanda, Senegal, Zambia, and Zimbabwe (recently Tanzania included) Angola, Burundi, Democratic Republic of the Congo, Liberia, Nigeria Due to potential increase in insecticide selection pressure on vector populations, it is important to monitor changes in species composition, behavior and susceptibility to insecticides

Entomological Monitoring Assess impact of IRS interventions on mosquito density, biting rate, behavior, parity and entomological inoculation rate Baseline data should be collected before IRS, and data should also be collected from the non-IRS control sites Assess quality of IRS operations and monitor the residual efficacy of insecticides sprayed Monitor insecticide resistance. In collaboration with the NMCP, research institutions and universities

Components of Entomological Monitoring in Project Countries Pyrethrum Spray Catches Indoor resting density Human Landing Catches Biting rates indoor & outdoor, EIR, Parity and peak biting time CDC Light Trap Collections As alternate to estimate biting rate indoors Where specimens are morphologically identified to the An. gambiae complex and An. funestus group, a sub-sample will need to be sent to a reference laboratory for molecular identification of species by PCR. The subsample size depends on the relative abundance of the samples, laboratory capacity, availability of budget.

Components of Entomological Monitoring in Project Countries cont. Insecticide Resistance Monitoring: to determine vectors susceptibility to insecticides currently in use or to be used in the future, and determine intensity of resistance At least one insecticide from each of the 4 classes of insecticides Regularly monitor at least once in a year, but frequency should be increased if there is increase in malaria WHO tube tests and CDC bottle assays Intensity assays and synergists assays All PMI/AIRS countries should collect data on resistance intensity The level of resistance intensity (percent survival at 5X and 10X the concentration of insecticides used to test for resistance) may provide information on the impact of IR on vector control intervention. In Zambia survival at 5X and 10X associated with blood fed mosquitoes in ITN areas

Mechanisms of resistance: Once resistance is suspected, the underlying mechanism of resistance should be identified. Metabolic resistance can be detected using CDC bottle assays Biochemical assays Target site resistance can be detected by PCR tests for kdr and acetyl cholinesterase resistance genes

Cone bioassay tests Monitor quality of spraying Determine residual life of insecticide Evaluate variations in different surface types Known susceptible laboratory reared mosquitoes should be used. If not available wild unfed females can be used as long as there is no resistance in the population.

Insecticide selections for IRS operations The choice of which insecticide to use should be made based on experts consultations At least six months before the spray operation Criteria includes Vector resistance Residual efficacy Risk to human health and environment, livestock and agriculture trade Acceptability to NMCP Cost

Conclusion Entomological monitoring is critically important for decision making process of IRS operations. It helps to understand if there is any impact on vector related indices and guide future interventions

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