Distribution of Leishmania major zymodemes in relation to populations of Phlebotomus papatasi sand flies

Zoonotic Cutaneous Leishmaniasis (ZCL) is caused by the parasitic protozoan Leishmania major, which is transmitted by the phlebotomine sand fly Phlebotomus papatasi. P. papatasi is also a vector of Leishmania arabica in Saudi Arabia [1,2], and of arboviruses in many countries [3,4]. Using various techniques like isoenzyme electrophoresis, polymerase chain reaction (PCR) and sequencing of different genes, L. major had been firmly identified in P. papatasi [5,6]. Many trypanosomatid infections have been recorded from wild sand flies [7]. However, many of these infections might have been other mammalian Leishmania species, or even lizard Sauroleishmania, as isolation and further characterization was not attempted. In countries north of Iran, much transmission of L. major, L. turanica and L. gerbilli is believed to occur in or near the burrows of the great gerbil Rhombomys opimus [8]. These burrows provide refuges for many sand fly species as well as for mammals and reptiles, making them a high risk habitat for the transmission of parasites to mammals and lizards [9]. In the former USSR, the distribution of L. turanica in rodents coincided with that of the sand flies P. papatasi [10]. The incrimination of a sand fly species as being the vector is complicated, Killick-Kendrick and Ward in 1981 established different grades of certainty; these include, anthropophily and geographic distribution in accord with the disease (Grade 1 and 2). Grade 3 requires that Leishmania be isolated from wild caught flies. Grade 4 establishes development of the parasite in the gut of the suspected vector. Grade 5 demonstrates experimental transmission of Leishmania by bite [11].To date, there is no vaccine or effective cure for leishmaniasis [12]. It is postulated that successful establishment of the disease in an endemic area is the outcome of a close association between the Leishmania parasite and its natural sand fly vector. This close relationship between the parasite and its correspondi