Diversity of trypanosomatids in small mammals from a forest fragment at the wildlife-urban interface in southeastern Brazil: implications for public health surveillance

Abstract This study investigated the diversity of trypanosomatids infecting small mammals in a fragmented forest landscape in southeastern Brazil, aiming to clarify their role in transmission cycles and assess potential public health risks. Eighteen individuals from three species - Didelphis albiventris (n = 8), Marmosops incanus (n = 4), and Nectomys squamipes (n = 6) - were captured in the Mata da Tapera Municipal Natural Park (MT), located within the Espinhaço Range Biosphere Reserve, Minas Gerais State. Xenodiagnosis using Lutzomyia longipalpis and Rhodnius neglectus, followed by 18S rDNA nested PCR, enabled the detection of Leishmania infantum, L. braziliensis, and Trypanosoma cruzi DTU TcI in insects fed on naturally infected hosts. Tissue and organ samples were also analyzed by in vitro culture and molecular diagnostics. Leishmania infantum was identified in D. albiventris (n = 2), L. braziliensis in M. incanus (n = 1), T. cruzi TcI in D. albiventris (n = 2), and Trypanosoma lainsoni in both D. albiventris and N. squamipes (n = 1 each), the latter representing the first record of this parasite in that rodent species. This integrated approach provides a valuable model for zoonotic surveillance at the wildlife-urban interface, enhancing diagnostic sensitivity and species identification. These findings confirm the presence of zoonotic trypanosomatids in a highly anthropized landscape and highlight transmission risks to humans and domestic animals, particularly in an area with active ecotourism, underscoring the need for targeted surveillance within a One Health framework. Author summary In many parts of Brazil, forested areas are getting smaller and more fragmented due to urban growth. These changes increase the contact between wild animals, domestic animals, and humans, creating new opportunities for diseases to spread. In this study, we examined small wild mammals living in a forest fragment close to human settlements in southeastern Brazil to find out if they carried parasites that can also infect humans. We used a combination of techniques, including allowing laboratory-raised insects to feed on these animals, to detect the presence of different parasites. We found that these mammals were naturally infected with species of Leishmania and Trypanosoma, including those that cause leishmaniasis and Chagas disease in humans. We also detected Trypanosoma lainsoni, a lesser-known parasite, for the first time in one rodent species. Our findings suggest that small mammals living in areas where forests meet cities may play an important role in maintaining and spreading parasites that affect public health. This study shows the importance of monitoring wildlife in changing environments and supports the idea that human, animal, and environmental health are deeply connected. Competing Interest Statement The authors have declared no competing interest.