Baseline insecticide susceptibility data of Phlebotomus papatasi in Iran.

BACKGROUND & OBJECTIVES Phlebotomine sandflies (Diptera: Psychodidae) play main role in the transmission of different forms of leishmaniasis in the world. Phlebotomus papatasi is the main vector of zoonotic cutaneous leishmaniasis (ZCL) in Iran. There are several control measures for vector control using different classes of insecticides. The aim of this study was to breed the sandflies which were collected from a hyperendemic focus of the disease in central Iran in the laboratory condition and to determine its baseline susceptibility to commonly used insecticides. METHODS Sandflies were collected from the field and were reared in insectary. Susceptibility tests were carried out on their generation. Baseline susceptibility of sandflies to DDT and pyrethroids was evaluated based on LT50 values. A total of 1305 specimens were tested using different time intervals. The LT50 and LT90 values were measured according to the WHO standard tests. The results were plotted using probit analysis and regression lines. RESULTS The results against female sandflies revealed the LT50 values of 1312.66, 253.66, 36.04, 9.38 and 6 sec to DDT (4%), permethrin (0.75%), deltamethrin (0.1%), cyfluthrin (0.15%) and lambda-cyhalothrin (0.05%), respectively. The figures for male sandflies were 1200.97, 310.10, 18.63, 6.08 and 0.77 sec respectively to the above insecticides. CONCLUSION The results of this study could help to provide a clue for implementation of currently used insecticides. Furthermore, a specific guideline is needed for monitoring and evaluation of insecticide susceptibility test against sandflies.