First Presentation of the Complete Infection Cycle of Visceralizing Leishmania infantum/ donovani Hybrid Strain in Turkey: The Host, Reservoir and Vector

Abstract

Objective: Visceral Leishmaniasis (VL) is a widespread infectious disease of the reticuloendothelial system which is mostly caused by Leishmania infantum and L.donovani. VL is a zoonotic infection and dogs act as the main reservoirs of the disease while the vectors are the female Phlebotomus, that is to say, sandflies. Although Leishmania spp. are attributed to reproduce asexually, the genetic exchange between different strains has recently been demonstrated and causes interspecific hybrids. We aimed to present the complete infection cycle of a hybrid strain of Leishmania infantum/donovani with the host, reservoir, and vector. Materials and Methods: A patient presenting with VL proved to have a dog with canine leishmaniasis. Bone marrow aspirate from the patient and lymph node aspirates from the dog were inspected for Leishmania spp. amastigotes under light microscopy. Samples were cultured in enriched NNN medium. Serological examinations were made using IFAT for the patient serum and rK39 test for both human and dog samples. Light traps were placed to collect Phlebotomus. Leishmania molecular identification was executed by primers and probes specific to ITS-1 and cytochrome B gene region of Leishmania parasites. Results: Leishmania spp. amastigotes were detected in the slides while promastigotes were present in the enriched NNN medium. For patient serum, IFAT IgG was 1/256 positive, and rK39 was positive for both dog and human samples. Fifty-two Phlebotomus were caught (24 male, 28 female): 35 of them were P. similis, ten were P. neglectus/syriacus, six were P .papatasi, and one was P. tobbi. Molecular analysis showed that the Leishmania spp. isolates from the patient, dog, and P.tobbi were identical. Gel image revealed two bands in all three samples, thus leading to the conclusion that the infecting strain was a hybrid of L. infantum and L. donovani. Conclusion: We found identical isolates that are putative hybrids of L. donovani and L. infantum in human, dog reservoir and sandfly.. Keywords: Leishmaniasis, Phlebotomus, Hybrid, Epidemiology, Migration, Turkey