PURPOSE: Hemoparasitism by T. minasense, T. devei, and T. cruzi has been reported in Callithrix jacchus and C. penicillata, which are invasive marmoset species in Rio de Janeiro. We aimed to investigate parasitism by Trypanosoma sp. in marmosets inhabiting Seropédica municipality in Rio de Janeiro, as part of the health monitoring efforts due to the proximity of these primates to the local population and the Universidade Federal Rural do Rio de Janeiro/UFRRJ campus. METHODS: Parasite species identification was performed through microscopy combined with PCR amplification, and DNA sequencing of ca. 700 bp fragment of the 18 S rRNA gene. Blood samples were collected from twenty-five marmosets: twelve free-living individuals from UFRRJ campus and thirteen in captivity at CETAS-RJ. RESULTS: Two individuals tested positive by microscopy for Trypanosoma sp., with morphometry within the range for T. minasense. Ten individuals were positive by PCR, confirming it as a more efficient methodology for this hemoparasite detection. Sequences of the 18 S rRNA showed similarity above 98% with T. minasense, clustering accordingly in the phylogenetic tree. Free-living marmosets presented a higher infection rate (58%) than captive animals (23%). CONCLUSION: The results suggest that captivity conditions may influence parasite transmission and fragmented landscapes maintain active trypanosomatid cycles, necessitating continuous surveillance in regions of increasing human-wildlife proximity.
Coimbra et al. (2026) studied this question.