Molecular studies on Leishmania infantum from cats in Brazil with novel insights about its transmission route.

Leishmania spp. are protozoan parasites responsible for zoonotic diseases known as leishmanioses. These parasites are primarily transmitted by infected sandflies; however, alternative transmission routes, such as vertical and venereal transmission, have been documented in humans and dogs. This study investigated the presence of Leishmania DNA in the reproductive organs of domestic cats in an area endemic for visceral leishmaniosis (VL). Conjunctival swabs from 302 cats, and reproductive tissues from 41 of these animals (34 males and 7 females) were analyzed by PCR targeting the kDNA and ITS1 regions of Leishmania. Positive samples underwent Sanger sequencing for species confirmation and phylogenetic analysis. In considering various samples tested, Leishmania DNA was detected in a total of three cats (1.0 %; 3/302), the three cats were positive for the PCR of reproductive tissue, while only two of them for the PCR of conjunctival swabs. Sequencing revealed high similarity (99.3-100 %) with L.infantum sequences obtained from humans hosts, and phylogenetic analysis confirmed that the sequenced samples clustered within the L.infantum clade. Although the frequency of positive cats was low, these results suggest the presence of L. infantum in the reproductive organs of cats, highlighting the need for further investigation into non-vector transmission routes in this species.