Serological and molecular survey of zoonotic visceral leishmaniasis in stray dogs (Canis familiaris) from an endemic focus in Meshkin-Shahr district in Ardabil province, Iran

Background & objectives: Visceral leishmaniasis (VL),a protozoan disease caused by Leishmania infantum is a major public health problem and cause of death among infants aged under 1 year and the elderly in endemic foci of Iran. The aim of this study is to determine the status of L.infantum infection in stray dogs from Meshkin-Shahr, a typical endemic area of VL in Iran. Methods: Sixty-eight randomly trapped stray dogs in Meshkin-Shahr area were tested for L. infantum infection using the direct agglutination test (DAT) from June to October 2016. The confirmation of seropositive samples was performed by Microscopic slides of spleen, culture and then PCR. The molecular methods performed by ITS1-PCR, RFLP-PCR and kDNA-PCR. The allof kDNA -PCR products were sequenced. Results: Out of 68 examined stray dogs, 17 (25.0%) were positive for L. infantum by DAT (1:320 titers or higher). Parasite test showed that all of seropositive samples have amastigote forms in their spleens but only 3 out of them could be cultured. The kDNA-PCR confirmed all of seropositive samples but ITS1-PCR and RFLP-PCR only confirmed 3 out of 17 (17.6%) seropositive samples. The sequenced products showed 94% homology with L. infantum. Interpretation & conclusion: The results showed a high prevalence of L. infantum infection in dogs in an endemic area of CVL and it provided key information for designing control programs against canine and human leishmaniasis.