Species of the Leishmania genus parasitize mammals in the New World and have life cycles alternating between vertebrates and invertebrates. Visceral Leishmaniasis is an important zoonosis which has wild and domestic canids as important known reservoirs, and the genetic diversity of Leishmania (Leishmania) infantum in Brazil it is not yet known. Leishmaniasis is a serious disease with a wide geographical distribution and an incidence of two million cases per year. In the current study we address the main aspects of Visceral Leishmaniasis.

OBJECTIVE: Trypanosoma theileri is the type species of the subgenus Megatrypanum, first registered in cattle in South Africa and East Africa. Cattle farms in the extreme south of the municipality of São Paulo and Embu-Guaçu, are characterized as subsistence, on small properties, and 500 head of cattle were registered in 2019. This work aimed to evaluate the occurrence of T. theileri in cattle from family farms in the extreme south of the city of São Paulo and in the municipality of Embu-Guaçu, SP, Brazil. METHODS: Parasitological and molecular diagnoses were carried out on samples taken from 68 cattle in small farms in the extreme south of São Paulo. RESULTS: The specific molecular diagnosis of T. theileri was 17.6% positive (12/68) and the parasitological diagnosis was 5.8% (4/68). CONCLUSION: Although considered non-pathogenic, its presence in the host may favor other parasitic and infectious diseases.