Occurrence of Leishmania infantum in Horses from Brazilian Amazon Arlei Marcili, Isadora Karolina Freitas de Sousa, Rejane dos Santos Sousa, Rafael Alves de Souza, Gabriel Ferreira Batista, Varley Cardoso Bosco, Thamiris Nascimento dos Santos, Bruna Alves Farias, Livia Mendes Miranda, Herbert Sousa Soares, Valéria Castilho Onófrio, Fernanda Ap Nieri-Bastos Vector Borne and Zoonotic Diseases, 2025 Background: Visceral leishmaniasis is a zoonosis distributed throughout Brazil and caused by the protozoan Leishmania infantum. The disease manifests in its visceral form, with dogs being the primary reservoir. Manaus is the largest city in the Brazilian Amazon region, and despite its significance, there are only documented cases of cutaneous leishmaniasis in humans. The aim of this study was to assess the occurrence of Leishmania infantum in horses in Manaus, Amazonas, Brazil. Materials and Methods: A total of 178 horses from 16 different properties within the city were sampled, and the specific molecular diagnosis was based on the L-like cathepsin gene. Results: Of the 178 horse samples, 82% were positive for L. infantum in the molecular diagnosis based on the L-like cathepsin gene, and of the 16 different properties sampled, only one did not have any positive animals. Conclusion: The role of horses in the transmission cycle of visceral leishmaniasis remains controversial, but the presence of infected horses before the appearance of human cases suggests that this host group could be considered sentinel, and their monitoring may serve as an early warning for the emergence of leishmaniasis in a given area.
Description of Four New Trypanosoma Species Infecting Small Wild Mammals from Two Brazilian Biomes: The Pantanal and Cerrado Hotspots Arlei Marcili, Andréa Pereira da Costa, Pablo Henrique Nunes, Juliana Isabel Giuli da Silva Ferreira, Renata Tonhosolo, Varley Cardoso Bosco, Isabella Pereira Pesenato, Fábio Fernandes Roxo, Fernanda Aparecida Nieri Bastos, Richard Campos Pacheco, Rogério Vieira Rossi, Thiago Borges Fernandes Semedo, Marina Tiemi Shio, Marcelo Bahia Labruna Microorganisms, 2025 The parasites of the genus Trypanosoma have a great diversity of vertebrate hosts and can be transmitted by several groups of invertebrates. All rodent and marsupial species are potential hosts of different trypanosome species. Most species descriptions of trypanosomes have been based only on morphological characteristics. In this study, we conducted a survey on trypanosome infection in small mammals that were caught in an area of the Brazilian Pantanal (Wetlands) and Cerrado (Savanna) biomes in the state of Mato Grosso. The trypanosomes isolated were included in phylogenetic studies based on the SSUrDNA and gGAPDH genes, which were complemented through morphological studies based on scanning and transmission electron microscopy. The morphological and biological discontinuities, along with the phylogenetic position, made it possible to describe four new species of trypanosome hosted by marsupials and rodents, which we described and named as Trypanosoma daniloi sp. nov., Trypanosoma favoritoae sp. nov., Trypanosoma percequilloi sp. nov., and Trypanosoma trefauti sp. nov.
