Low helminth richness in a Mico melanurus population: morphological and diagnostic data from a fragmented urban area of Brazilian Cerrado

Objective: To identify the occurrence of gastrointestinal parasites in Mico melanurus within the Cerrado biome of an urban area in Brazil, supplemented by morphometric and morphological analyses. Methods: Helminths were collected from 21 M melanurus specimens in Cuiabá, located within the Brazilian Cerrado. Specimens were obtained opportunistically from animals found dead from October 2020 through February 2022 in accordance with the Replacement, Reduction, and Refinement principles to avoid additional impacts on wild populations. These individuals recovered postmortem within the urban perimeter and underwent necropsy and parasitological screening. Parasites isolated from the gastrointestinal tract were fixed in 70% ethanol for morphological identification. Results: Trypanoxyuris spp was identified from 2 samples (mean intensity and abundance of 63 and 6, respectively). In contrast, Primasubulura jacchi was identified from the other 19 samples (mean intensity and abundance of 58.2 and 52.7, respectively). Conclusions: This study revealed low parasite richness, as only 2 helminths species were identified. This low parasite richness may be associated with the impact of habitat fragmentation in an anthropized area, indicating an imbalance in the monkeys' habitat. Clinical Relevance: Identification of the gastrointestinal helminths infecting free-ranging M melanurus provides baseline data for veterinary diagnosis, health assessment, and parasite surveillance in wild primates. These findings may assist wildlife veterinarians in interpreting gastrointestinal disease, monitoring population health, and developing evidence-based management strategies for conservation programs.