Zoonotic pathogens of vervet monkeys (Chlorocebus pygerythrus) in Malawi

Wild troops of vervet monkeys (Chlorocebus pygerythrus) live in the heart of Lilongwe, the capital city of Malawi, resulting in interactions at the human/wildlife interface. One wild urban troop has been observed on the... [ view full abstract ]

Wild troops of vervet monkeys (Chlorocebus pygerythrus) live in the heart of Lilongwe, the capital city of Malawi, resulting in interactions at the human/wildlife interface. One wild urban troop has been observed on the grounds of a wildlife rescue and rehabilitation center located within the city limits, home to captive monkeys and frequented by tourists. The wild monkeys have been observed in close contact with both animals housed at the wildlife center and visitors. The wildlife center prevents introduction of disease through quarantine, a preventative health program for center residents, and staff health policies. Our objective was to investigate the risk these wild monkeys posed as a source of fecal pathogen exposure for sanctuary animals. For two months of the cool dry season, this troop of vervets was followed and behavioral observations were collected along with opportunistic fecal samples. Scan sampling was used to gather activity data and feces were examined for parasites using direct fecal smear, magnesium sulfate floats, sugar floats, salt floats, Giardia snap tests and Shaudinn's fixative with trichrome staining. The troop was found to be carrying potential zoonoses such as Trichuris spp., Strongyloides spp.,Trichomonas spp., Giardia spp., and Balantidium coli. The troop was observed to be spending the majority of their time foraging in areas of human habitation and contact with sanctuary animals or other wild monkey troops was less common. Recorded observations between the troop and humans included indirect contact such as foraging at waste site, and direct interactions (e.g. hand feeding of the monkeys). The wild monkeys did pose a risk for fecal pathogen introduction into the center, but the potential for transfer of zoonoses/anthroponoses between humans and monkeys may be of greater concern and warrants further investigation.