Effect of untreated bed nets on blood-fed Phlebotomus argentipes in kala-azar endemic foci in Nepal and India

Observational studies in the Indian subcontinent have shown that untreated nets may be protective against visceral leishmaniasis (VL). In this study, we evaluated the effect of untreated nets on the blood feeding rates of Phlebotomus argentipes as well as the human blood index (HBI) in VL endemic villages in India and Nepal. The study had a "before and after intervention" design in 58 households in six clusters. The use of untreated nets reduced the blood feeding rate by 85 percent (95 percent CI 76.5-91.1 percent) and the HBI by 42.2 percent (95 percent CI 11.1-62.5 percent). These results provide circumstantial evidence that untreated nets may provide some degree of personal protection against sand fly bites.