Natural infection and phylogenetic classification of Leishmania spp. infecting Rhombomys opimus, a primary reservoir host of zoonotic cutaneous leishmaniasis in Northeast Iran.

Background: In the northeast and central parts of Iran, Rhombomys opimus (great gerbil) is the primary reservoir host of zoonotic cutaneous leishmaniasis (ZCL). This study used both parasitological and molecular methods to identify Leishmania spp. and their different haplotypes that were circulating in the great gerbil populations in ZCL foci from northeastern Iran.

Methods: A cross-sectional study using microscopy, culturing and molecular methods was conducted to detect Leishmania parasites in 194 live R. opimus in ZCL foci from northeastern Iran during 2010-2011.

Results: Leishmania spp. were found in 38.1% (74/194) of the samples by microscopy and in 41.2% (80/194) by culturing. Small papules and skin thickening on the upper edge of the ears were observed in 25 (12. 9%) of the R. opimus. PCR-RFLP and PCR direct sequencing of internal transcribed spacer 1 (ITS1) rRNA showed similar infection rates for L. major and L. turanica in 60 eligible R. opimus, only one mixed infection containing both L. major and L. turanica was found. Phylogenetic analysis was conducted using the ITS1 sequences of 32 isolates that were successfully aligned by comparison of their base sequences with the ITS1 DNA sequence database using ClustalW and MEGA5. The samples were classified into monophyletic clusters (>97% bootstrap). Six haplotypes were observed for L. major and seven for L. turanica.

Conclusion: In northeast Iran, L. major, and L. turanica naturally circulate in R. opimus, and L. major/L. turanica co-infections also exist. Phylogenetic analysis suggested that Leishmania spp. isolated from R. opimus are not a monophyletic group.