Identification and frequency distribution of Leishmania (L.) major infections in sand flies from a new endemic ZCL focus in southeast Iran

Zoonotic cutaneous leishmaniasis (ZCL) is an important public health challenge in Iran. It is often caused by the protozoan parasite, Leishmania major. This pathogen is principally transmitted by the infectious bites of adult female phlebotomine sand flies which belong to the subgenus Phlebotomus (Phlebotomus) Rondani and Berte (Diptera: Psychodidae). A recent outbreak of clinical ZCL cases in the rural district of Jask, Hormozgan province, southern Iran prompted the identification of sand flies naturally infected with L. major using polymerase chain reaction (PCR) and enzyme-linked immunosorbent assay (ELISA). A total of 8,123 wild sand flies were caught using sticky paper traps indoors and outdoors in seven villages of Jask from March 2007 to February 2008. About 120 trap-nights per month were carried out during peak seasonal density. Eight sand fly species of two distinct genera were morphologically identified. The most abundant species, Phlebotomus papatasi (≈60?%) and Phlebotomus salehi (17?%), had simultaneous population peaks in May and October. The anthropophilic index of P. papatasi was approximately twice that of P. salehi. PCR reactivity of L. major infections in P. salehi was weaker than those in P. papatasi. This is discussed with regard to their role in the natural transmission cycle of ZCL. This study provided the first PCR and ELISA evidence on P. salehi as a vector of L. major parasites in a new endemic region of ZCL in southeast Iran.