Molecular characterization of Leishmania spp. isolated from Brazilian stray dogs from an endemic area for canine visceral leishmaniasis

Canine visceral leishmaniasis (CVL) is a worldwide anthropozoonosis caused by an intracellular parasite protozoan, Leishmania spp. In Americas, Leishmania (Leishmania) infantum is the causative agent, transmitted by sandflies, Lutzomyia longipalpis, after blood meal in domestic dogs, the main reservoir. The present study was aimed to determine the occurrence of Leishmania spp. and L. infantum in peripheral blood, and popliteal lymph node and bone marrow aspirate samples of 164 Brazilian stray dogs from an endemic area for CVL using the Polymerase Chain Reaction (PCR). For Leishmania spp., 56 (34.15%; 27.32-41.71%) blood, 102 (62.20%; 54.56-69.26%) lymph node, and 115 (70.12%; 62.71-76.60%) bone marrow samples tested positive, whereas 46 (28.05%; 21.74-35.38%), 94 (57.32%; 49.65-64.64%), and 114 (69.51%; 62.07-76.04%), respectively, resulted positive for L. infantum. Restriction Fragment Length Polymorphism (ITS1-RFLP) and sequencing were used to characterize the positive samples to Leishmania spp., but negative to L. infantum. Twenty (10 blood, 9 lymph node and 1 bone marrow) samples were characterized and matched the L. donovani complex species, with 99-100% similarity to L. donovani complex species (GenBank accession n.KC998879.1, JQ730002.1, GU045591.1, HQ830353.1, HM130608.1). The present study reports a high prevalence of stray dogs infected with leishmania species responsible for VL in the studied area, in which the observed diversity of leishmania species may contributes for further epidemiological studies.