Water buffaloes (Bubalus bubalis): potential reservoirs of trypanosomatids in endemic areas.

Trypanosomatids are protozoan parasites that include the genera Trypanosoma and Leishmania, which infect a wide range of mammalian species, including humans and ruminants. This study aimed to assess the presence of Trypanosomatid parasites in water buffaloes (Bubalus bubalis) using molecular techniques. Blood samples and conjunctival swabs from the right and left eyes were collected from 100 buffaloes (44 females and 56 males). PCR analysis detected Trypanosomatids in 32% (32/100) of the buffaloes: 29% (29/100) tested positive for DNA extracted from blood, and 4% (4/100) tested positive from conjunctival swab samples. Using the Fluorescent Fragment Length Barcoding (FFLB) technique, 38% (38/100) of blood samples were positive for Trypanosomatids, with 35% (35/100) identified as Trypanosoma theileri and 3% (3/100) as Trypanosoma vivax. Direct sequencing and analysis of PCR amplicons from four buffaloes revealed that three samples matched 100% with Trypanosoma theileri, while one matched 100% with Leishmania infantum. Our findings confirm that buffaloes can serve as hosts for Trypanosomatids and support previous observations that these parasites are often underdiagnosed. This is the first report of Leishmania infantum DNA in buffalo conjunctival swabs in Brazil and the first detection of Trypanosoma vivax DNA in buffaloes in the city of Andradina and in São Paulo state. These findings underscore the need for further studies to clarify the role of buffaloes in the epidemiology and dissemination of trypanosomatids in livestock populations.