Prevalence and molecular characterisation of intestinal parasites infecting non-human primates in natural and captive conditions

Non-human primates (NHPs) have been found infected with a diversity of intestinal zoonotic protozoan and metazoan parasites of public health concern. Ecosystem transformation increases the contact between human and NHPs, incrementing the chances of zoonotic parasite transmission. Likewise, contact with captive NHPs can represent a risk for humans, leading to parasitic infections. This study aimed to assess the prevalence of intestinal parasites in NHPs living in two scenarios, fragmented forests in Colombia and captive conditions in Italy (two wildlife recovery centres and a zoological garden),to molecularly characterise selected parasite species of zoonotic interest (Blastocystis sp., Giardia sp., Ascaris sp., Trichuris sp.), and to provide a preliminary description of the distribution of parasite taxa in different ecological contexts. Faecal samples were collected from free-ranging Alouatta seniculus, Ateles hybridus, Aotus griseimembra, Cebus versicolor, Saimiri cassiquiarensis, and Sapajus apella in Colombia, as well as fromcaptive Macaca tonkeana, Macaca fascicularis, and Sapajus apella living at the wildlife recovery centre Parco Faunistico Piano dell’Abatino, in Rieti (Lazio region). Two hundred twelve and 33 faecal samples were collected from free-ranging and captive NHPs, respectively. Flotation and faecal smears were performed in order to identify parasites based on morphology. Samples microscopically classified as positive for Blastocystis sp, Giardia sp. and Ascaris sp. were processed for molecular characterisation. Additionally, one carcass of M. fuscata from Fondazione Bioparco di Roma (Rome, Lazio) and one of M.fascicularis from Centro Recupero Animali Selvatici della Maremma (Semproniano, Tuscany) were necropsied and intestinal adult nematodes were collected, morphologically identified, and molecularly characterised. About 93% of the samples from free-ranging NHPs were positive for intestinal parasites, including: protozoans (Blastocystis sp., Balantidium sp., Dientamoeba fragilis-like, Entamoebidae, Giardia sp.), cestodes (Hymenolepis sp.), trematodes (Controrchis sp.), nematodes (Ascaris sp., Strongyliform larvae, Trypanoxyuris sp., Ancylostomatidae), and acanthocephalans. Ascaris lumbricoides, Giardia intestinalis (Assemblages A and B) and Blastocystis hominis (Subtype 8) were identified through molecular techniques, from samples of free- ranging NHP. Captive primates were found infected with protozoans (Entamoeba coli, Dientamoeba fragilis-like, Iodamoeba bütschlii, Balantidium sp.) and nematodes (Oesophagostomum sp., strongyliform larvae, Trichuris sp.). The collected adult nematodes were morphologically identified as whipworms (genus Trichuris) and after molecular characterisation, the phylogenetic analyses grouped Trichuris specimens from M. fuscata into a host- specific branch of the Trichuris trichiura complex of species, while whipworms from M. fascicularis clustered within a less specific clade formed by Trichuris infecting several primate species, including humans. This study provides new information of intestinal parasites infecting wild NHPs exposed to anthropogenic disturbance and captive conditions. The finding of parasites with zoonotic potential suggests epidemiological implications in NHP conservation and human health, at the human-NHP interface, in transformed ecosystems. Additionally, the results of this study could be useful in the design of public health policies, and within NHP conservation programs.