Effects of long-lasting insecticidal nets and zooprophylaxis on mosquito feeding behaviour and density in Mwea, central Kenya

Abstract

Background & objectives: Zooprophylaxis is a strategy that can control malaria by attractingmosquitoes to domestic animals that act as dead-end hosts. The objective of this study was toestablish the effects of zooprophylaxis and long-lasting insecticidal nets (LLINs) on malariatransmission in an agro-based ecosystem with seasonal transmission.Methods: The mosquito samples were collected indoors using the space spray catch method beforeand after intervention between October 2005 and March 2006 to determine the mosquito densitiesand the feeding patterns of Anopheles spp in Mwea, Kenya.Results: A total of 4148 mosquito samples were collected, out of which 11 (0.2%) were testedpositive for sporozoites. Ten were Anopheles gambiae species and one was An. funestus species.Results on blood meal ELISA showed that in the household categories that used bednets and keptone cow there was a decrease in relative change ratio (post-/pre-intervention) of 87.5 and 19.6%(p 0.05). In households with >4 cattle andbednet, there was significant reduction (p 4 cattle.Interpretation & conclusion: This study demonstrated that there were additive effects of zooprophylaxisand LLINs in the control of mosquito density and reduction of human risk to themosquito bites. However, in Integrated Vector Management (IVM), the number of animals perhousehold should not be more than four.

Keywords

• Cattle biting index
• human biting index
• long-lasting insecticidal nets
• man biting rates
• mosquitoes
• zooprophylaxis