EFFECT OF ADMINISTERING IVERMECTIN TO DOMESTIC ANIMALS ON MORTALITY, FECUNDITY AND SURVIVORSHIP OF ANOPHELES ARABIENSIS

Abstract

Global trends in malaria incidence and mortality has declined in many malaria endemic countries due to the massive scale-up of indoor based malaria control interventions. However, the impact of these interventions has been restricted due to insecticide resistance, the animal and outdoor biting behaviors of malaria vectors. Hence, approaches to target insecticide resistant and zoophilic vectors are urgent. This study was designed to evaluate the effect of treating cattle ivermectin on mortality, fecundity and survivorship of laboratory reared Anopheles arabiensis. Three calves were randomly selected to receive a subcutaneous injection of ivermectin at the therapeutic dose of 0.2 mg/kg of body weight, while the other two calves received no treatment and used as control. Five tents were constructed for the trial. The calves were introduced into the tents (one per tent) and then, 30 starved An. arabiensis were released into each tent. Only fully engorged females were collected from each tent. Later, their mortality, survivorship and fecundity were recorded. Data analysis was done using SPSS version 16. Over all, ivermectin had significant effect on the mortality, survivorship and fecundity of An. arabiensis. The mean mortality rate of An. arabiensis was 81.6% at day one after treatment. The survivorship of An. arabiensis was significantly reduced after feeding on ivermectin treated compared to those fed on control calves (F= 110.7, DF = 1, P < 0.001). The effect was significantly affected by the interaction of treatment and day after injection (F = 15.13, DF = 4, P < 0.001). Those mosquitoes fed on calves treated with ivermectin produced significantly lower number of eggs compared to control groups (F = 435.3, DF = 4, P < 0.001). In conclusion, ivermectin had impact on mortality, fecundity and survivorship of laboratory reared An. arabiensis. However, further study could be recommended on the impact of treatment of cattle with ivermectin on wild vector population, and combining the use of existing indoor based interventions with mass ivermectin administration for domestic animals.