Abstract:
Due to challenges of controlling leishmaniasis in Kenya through the vector, the efficacy of pyrethrin EC (Pymos™ 0.6% W/V) a mosquito adulticide was evaluated against Phlebotomus duboscqi while incorporated in sucrose as a possible complementary method. Pyrethrin was prepared into concentrations of 0.08, 0.25 and 0.5 mg/ml using 10% sucrose. Ten male and female sand flies were each aspirated into jars and fed separately with the prepared solutions using cotton wool pads placed atop experimental jars and mortality monitored each day. The experiments were replicated three times. Significant mortality (P< 0.05) for both sexes was observed. The concentration of 0.08mg/ml gave low adult mortality in 24 hours but amplified with time. In the 0.25 bioassay, mortality of females was 10(33.3%) and males had 21 (70%) in 24 hours. The LD50 for females and males tied at 0.1 mg/ml in 48 hours of exposure. The concentration of 0.25 mg/ml was ideal at 48 hours of feeding where majority of the sand flies succumbed to the insecticide. There were significant mortality differences (PP>0.05) was observed in male and female mortality at 48 hours of exposure however. Although we cannot rule out sand fly mortality due to contact with the test material, the results of this study however suggest that control strategies using low-dose pyrethrin-sugar combinations as baits may be effective against phlebotomine sand flies and other sugar feeding pests of medical importance.
