Résumé
Background: TheOnchocercidaeisafamilyof larialnematodeswithseveralspeciesofmedicalorveterinaryimpor- tance. Micro lariae are found in the blood and/or the dermis and are usually diagnosed in humans by microscopy exami- nation of a blood sample or skin biopsy. The main objectives of this study were to evaluate whether lariae DNA can be detected in faecal samples of wild non-human primates (NHPs), whether the detected parasites were closely related to those infecting humans and whether larial DNA detection in faeces is associated with co-infections with nematodes (Oesophagostumum sp. and Necator sp.) known to cause blood loss while feeding on the host intestinal mucosa.Methods: A total of 315 faecal samples from 6 species of NHPs from Cameroon and Gabon were analysed. PCRs targeted DNA fragments of cox1 and 12S rDNA genes, to detect the presence of lariae, and the internal transcribed spacer 2 (ITS2), to detect the presence of Oesophagostomum sp. and Necator sp. infections.Results: Among the 315 samples analysed, 121 produced sequences with > 90% homology with Onchocercidae reference sequences. However, 63% of the 12S rDNA and 78% of the cox1 gene sequences were exploitable for phylo- genetic analyses and the ampli cation of the 12S rDNA gene showed less discriminating power than the ampli cation of the cox1 fragment. Phylogenetic analyses showed that the cox1 sequences obtained from ve chimpanzee DNA faecal samples from Gabon and two from Cameroon cluster together with Mansonella perstans with high bootstrap support. Most of the remaining sequences clustered together within the genus Mansonella, but the species couldnot be resolved. Among the NHP species investigated, a signi cant association between larial DNA detection and Oesophagostomum sp. and Necator sp. infection was observed only in gorillas.Conclusions: To our knowledge, this is the rst study reporting DNA from Mansonella spp. in faecal samples. Our results raise questions about the diversity and abundance of these parasites in wildlife, their role as sylvatic reservoirs and their potential for zoonotic transmission. Future studies should focus on detecting variants circulating in both human and NHPs, and improve the molecular information to resolve or support taxonomy classi cation based on morphological descriptions.