Beyond reptiles: the fire salamander as a potential host for Leishmania (Sauroleishmania) tarentolae

Leishmania parasites are dixenous protozoans transmitted by phlebotomine sand flies and known to infect a range of vertebrate hosts, including mammals, birds, and reptiles. However, to date, there is only a single record for amphibians, in a toad (order Anura), based on molecular evidence. In this study, we present the first evidence supporting the potential of Leishmania to infect an amphibian host, the fire salamander (order Urodela), through combined molecular and morphological approaches. A total of 78 salamanders were sampled from a protected area in northern Italy. Single cells morphologically similar to Leishmania were observed in 4.48 % of Giemsa-stained blood smears. Leishmania-specific qPCR coupled with high-resolution melting (HRM) analysis detected parasite DNA in 7.14 % of blood samples and 12.12 % of cloacal swabs. Sanger sequencing of a qPCR-positive sample and phylogenetic analysis identified the parasite as Leishmania (Sauroleishmania) tarentolae. These findings may contribute to expand the known host range of Leishmania to include Urodelan amphibians, suggesting that these vertebrates may play an unrecognized role in the ecology and transmission dynamics of these parasites.