Molecular Detection of Leishmania in Wild Caught Sand Flies of Larroussius Subgenus in Iran: Combined Use of Internal and External Morphological Characters as a Mean to Differentiate Morphologically Similar Females.

Objective: Phlebotomine sand flies are the primary vectors of leishmaniasis; visceral form of disease is transmitted mainly by species belonging to Larroussius and Adlerius subgenus. Species identification of some females in Larroussius subgenus is not easy due to the high similarity. Accurate species identification enables control operations to target only main vectors and increase understanding of ecological needs, bionomic characteristics, and behavioral traits. The purpose of current study was to use two approaches based on internal and external morphological characters to identify the wild caught of female specimens belonged to Larroussius subgenus and investigate Leishmania infection.

Methods: Totally, 128 specimens belonging to Larroussius' subgenus were collected from a VL focus in northwestern Iran, species differentiation was done by two approaches proposed in literature: (1) characters of pharyngeal armature, number of Spermathecal segment, length of spermathecal neck, palpal and ascoid formulae; (2) blindly on the basis of the shape of the base of spermathecal duct. Their potential infection to Leishmania was investigated by kDNA-Nested-PCR.

Results: The results of species identification were consistent based on two methods. Among three identified species, Phlebotomus perfiliewi was found to be the dominant species, followed by Ph. neglectus and Ph. tobbi. Two specimens of Ph. perfiliewi were found to be infected by Leishmania infantum, which emphasizes the role of this species in VL transmission in study area.

Conclusion: It is suggested that combination of the characters used here be considered for species identification of female of Larroussius subgenus to take advantage of maximum characters, especially where species present sympatrically.