Detecção molecular e análise filogenética de filarídeos em primatas Sapajus apella da região geográfica imediatada de Bacabal, Maranhão

Abstract

Filarids are nematodes belonging to the superfamily Filarioidea, recognized for infecting various groups of vertebrates, including Neotropical primates. In Brazil, despite the wide distribution and diversity of species of the genus Sapajus, studies aimed at detecting these parasites in wild populations are still scarce. In Maranhão, particularly in the Immediate Region of Bacabal, an ecological transition area between biomes, with high biodiversity and interaction between wildlife and anthropogenic environments, no studies have yet been carried out on filarids in free-ranging Neotropical primates. In this context, the present study aimed to perform the molecular detection and phylogenetic characterization of filarids detected in Sapajus apella from the region. Between September 2024 and January 2025, individuals of the species S. apella were captured using Tomahawk traps. After restraint, blood samples were collected by puncture of the jugular or femoral vein. Part of the samples was used for the preparation of blood smears, stained by the panoptic method, while another fraction was used for genomic DNA extraction using the QIAamp DNA Mini Kit (QIAGEN®, Germany). The extracted DNA was amplified by Polymerase Chain Reaction (PCR) targeting the cox1, 18S, and 12S genes, followed by Sanger sequencing. The sequences obtained for the cox1 gene were analyzed by BLAST and used for phylogenetic inference by the Maximum Likelihood method. Drops of blood were added to LIT medium for Trypanosoma culture for a parallel project. Of the 14 individuals of S. apella analyzed, three (21.43%) individuals were positive with the presence of parasitic forms in blood smears. Regarding PCR, six (42.85%) samples were positive for the cox1, 18S, and 12S genes. All amplified samples were submitted to sequencing; however, for the cox1 gene, four of them (66.7%) presented adequate quality for analysis and were used in the construction of the phylogenetic tree. The sequences obtained showed identity between 96% and 99% with Dipetalonema gracile according to BLAST, clustering exclusively within the clade of the genus Dipetalonema. The results confirm the occurrence of filarids of the genus Dipetalonema in S. apella in Maranhão. This study represents the first record of the presence of this parasite in primates of this species in the state, expanding knowledge about the distribution of filarids in Neotropical primates in Brazil.