Abstract
Non-human primates (NHP) are infected with many species of parasites ranging from protozoa to helminths. The high prevalence of certain parasitic infections in NHP may make these animals reservoirs of potentially zoonotic pathogens. Mansonella sp. are among the filariae that infect NHP, and M. perstans is widespread in sub-Saharan Africa where there is a large NHP population. Microscopic observation of blood samples is the standard method of diagnosis of M. perstans. However, one of the major obstacles in diagnosing blood-borne parasites in HNPs remains to obtain a blood sample. With evidence obtained in 2010 of the possibility of using feces to test for blood-borne parasites, we hypothesized that it would be possible to detect M. perstans DNA in the feces of NHP, but also that the presence of filarial DNA in feces would be associated with co-infections with Oesophagostomum sp., Necator sp. Many soil-transmitted helminths (STH) are shared between humans and NHP: notably Trichuris sp., Oesophagostomum sp., Ascaris lumbricoides, hookworms. In the second part of this thesis, we studied epidemiology and genetic diversity of these STH in wild NHP living in Cameroon and Gabon.We analyzed feces of NHP collected in Cameroon and Gabon for DNA of filaria of the genus Mansonella sp. and of STH: Trichuris sp., Oesophagostomum sp., Ascaris, and hookworms. We also analyzed sequences of M. perstans obtained from blood samples of patients suffering from mansonellosis in Cameroon. We obtained 121 sequences identical to the reference sequences of Onchocercidae. The cox1 sequences were grouped with the reference sequences of M. perstans, and those of Cameroonian patients carrying the filaria. The association between the presence of filarial DNA in feces and infection with Oesophagostomum sp. and Necator sp. was statically significant only in gorillas. Necator sp. infections were most common in gorillas, but were also present in chimpanzees, and one greater spot-nosed monkey. Oesophagostomum was frequently observed in gorillas, followed by chimpanzees, mandrills, and mangabeys. Necator and Oesophagostomum co-infection was most frequently observed in chimpanzees and gorillas. Only one gorilla, one chimpanzee, and one greater spot-nosed monkey were infected with Trichuris sp. Among the Necator sequences, five different variants (NH1-NH5) of ITS2 were detected. The NH5 haplotype is clustered with a Necator sp. sequence from a human in the Central African Republic. The Oesophagostomum sequences clustered into three different clades probably representing three distinct species infecting the NHP studied. The Trichuris sequences were grouped into a clade containing sequences of T. trichiura and Trichuris sp. from humans and NHP.In conclusion, we detected for the first time the DNA of Mansonella sp. in the fecal material of NHP. This thesis provides data on the prevalence and genetic diversity of Mansonella sp. and GH in NHP from Cameroon and Gabon. As these data are not sufficient, future research should use several molecular markers and next-generation sequencing for better identification of Mansonella, Necator, and Oesophagostomum species infecting NHP. These studies should be expanded, not only to domestic animals but also to the human population living on the edge of parks.