Infecção por filárias em Saguinus midas (Linnaeus, 1758) e Saguinus bicolor (Spix, 1823) na Amazônia Central

Abstract

The Saguinus bicolor is a neotropical primate of the callitrichid group that is in a critically endangered state, mainly due to the loss of its natural habitat. Thus, anthropogenic actions have promoted deforestation, fragmentation, change in land use, degradation, and the loss of quality of the natural resources available to the species. In addition, in this anthropized environment, S. bicolor is also exposed to roadkill, electrocution, mistreatment, and domestic animal attacks. Likewise, other natural pressures occur, such as the expansion of Saguinus midas into its geographic distribution area, where a sympatric relationship between the primates may favor the transmission of filariae and impair the conservation of S. bicolor. Filariae of the family Onchocercidae are agents responsible for zoonotic diseases of global relevance, and may affect several hosts such as primates and other mammals, including humans. The recognized host interspecificity of filariae in Neotropical Primates favors their transmission within this group. Moreover, their transmission involves bridge vectors, some of which are anthropophilic insects that can transmit filariases recognized as neglected tropical diseases. In this regard, in areas close to urban centers where S. bicolor occurs, the emergence of zoonoses with pathological and epidemiological potential, not yet elucidated, would be possible. The aim of this study was to conduct a survey of filariae present in free-ranging S. midas and S. bicolor and to verify whether there is sharing of filariae between these hosts. In the study, 53 primate carcasses from the Project Sauim-de-Coleira at UFAM were used, 30 of S. midas and 23 of S. bicolor, most of which died due to roadkills. At IFAM, necropsies were performed to search for adult filariae and collect biological material, such as transudate present in the abdominal and thoracic cavities, and nodules in the subcutaneous spaces adjacent to these cavities and the upper limbs. Morphological identification of adult filariae was performed by preparing temporary slides, and of microfilariae by smears of the collected transudate, stained using the rapid Panoptic method. Eleven adult filariae compatible with Dipetalonema gracile were collected from S. midas, with an occurrence of 13.3% (4/30). In the examination of the transudate, S. midas presented microfilariae in 20.0% (4/20) of the samples, while in S. bicolor they were observed in 56.52% (13/23) of the samples. Four species of microfilariae were identified as compatible with D. gracile, Mansonella cf. mystaxi, Mansonella cf. marmosetae, the last two recorded for the first time in these hosts and Mansonella mariae, which was reported for the first time in S. midas. Most infections occurred as coinfections, and the Jaccard index indicated complete overlap of filarial species, suggesting possible sharing between the two primates. Despite this similarity, the analysis of microfilarial abundance revealed marked differences in the dynamics of infections, with M. mariae predominating in S. bicolor. These results, together with the novelty of the records, highlight the importance of further molecular and epidemiological studies to assess parasite sharing, particularly in areas of species overlap, the dynamics of transmission, and the potential risk of zoonoses, which are key aspects both for the conservation of S. bicolor and for public health in the Amazon.