Occurrence of low density of Leishmania infantum in sandflies from a new focus of visceral leishmaniasis in northwest of Iran

Background & objectives: Observations and case studies have shown that the number of Visceral Leishmaniasis (VL) cases have increased in the recent years in several areas of Iran including Sarab district, East Azerbaijan province. Sarab district has been considered as a new focus of VL in Iran. The density of the sandfly vector and the Leishmania parasites causing infection has been assessed in 2009. Methods: Sandfly species had been collected from Sarab district, East Azerbaijan province in 2009 using sticky papers and CDC traps. DNA of sandflies was extracted and nested PCR was amplified in a region of the ribosomal RNA amplicon of Leishmania (ITS1-5.8S rRNA gene), which was shown to be species-specific by DNA sequence. Results: Altogether, 1317 male and female sandflies were trapped. At least 10 different sandfly species were identified morphologically. Leishmania infantum was the only Leishmania that was detected among the sandfly’s population in Sarab district. All the infectious cases (4/223) found in the abundant sandfly region were Phlebotomus kandelakii. Conclusion: The diversity of sandflies was similar to those in the main VL focal points in Iran, but the diversity of parasite and density were significantly lower. The low prevalence of VL in Sarab district might be explained by the scarcity of infected domestic dogs Canis familiaris the primary reservoir host of VL in the region. By finding the L. infantum in P. kandelakii for the first time on this new focus, we are able to conclude that P. kandelakii might be the vector of L. infantum. In future, more works should be done to test status of P. kandelakii as a proven vector of L. infantum.