Assessing the insecticide susceptibility status of field population of Phlebotomus papatasi (Diptera: Psychodidae) in a hyperendemic area of zoonotic cutaneous leishmaniasis in Esfahan Province, Central Iran

Leishmaniasis is a Neglected Tropical Disease (NTD) and emerging parasitic infection that affect mainly poor regions around the world. This study aimed to determine the baseline susceptibility of Phlebotomus papatasi to commonly used insecticides in a hyper endemic area using WHO standard procedure in central Iran. A total of 4–5 replicates containing 120–200 sand flies were used for each insecticide. Baseline susceptibility to DDT and pyrethroids was assessed on 5326 specimens collected from the study area. The LT50 and LT90 values were measured according to the World Health Organisation test using probit analysis and regression lines. The test results against males P. papatasi revealed that LT50 values to DDT 4%,Permethrin 0.75%, Deltamethrin 0.05%, Cyfluthrin 0.15% and Lambdacyhalothrin 0.05% were 564.07, 38.08, 1.95, 0.60 and 9.78 s and the figures for females were 584.44, 110.10, 11.64, 1.53 and 16.91 s, respectively. Our results indicated that P. papatasi as the main cutaneous leishmaniasis vector was susceptible to Cyfluthrin 0.15%, Lambdacyhalothrin 0.05%, Permethrin 0.75% and Deltamethrin 0.05% and tolerant to DDT 4%. This study was carried out in one out of many Leishmaniasis foci in Iran. We recommend that future studies incorporate other regions and use the same procedure for monitoring and evaluating sand fly resistance. Also, WHO can provide a specific guideline and create a test kit for sand fly resistance monitoring and for applying susceptibility test because the tubes prepared for mosquitoes are not actually fit for sand flies