Host-parasite Ecology of the Helminths in Mountain Gorillas

To understand patterns of intestinal parasitism in healthy, undisturbed endangered mountain gorillas (Gorilla beringei), we regularly collected fecal samples from a group of 14 wild gorillas residing in Bwindi Impenetrable National Park (BINP), Uganda, for about 1 yr. The objectives of the study were to collect baseline data in order to document the helminth parasites infecting this group of gorillas and to examine the effects of season and host age-sex class on patterns of parasite infection. In addition to weekly surveys of feces from all group members, fecal samples from 4 identified individuals were examined almost daily. We identified the diagnostic stages of the following parasites: strongylids (Strongylida), Anoplocephala gorillae, Probstmayria sp., Strongyloides fuelleborni, and a trematode. Monthly and daily fluctuations in strongylid egg counts were observed. Infants had lower strongylid egg counts compared with other group members. Both of the silverbacks had higher mean egg counts in the wet season than in the dry season. Examination of fecal samples from identifiable gorillas revealed high day-to-day variation in strongylid egg counts. No evidence of anthropozoonotic transmission of intestinal helminths was found.