Gastrointestinal parasites infecting ungulates, felids and avian species at National Zoological Gardens of South Africa

Abstract

Zoological gardens are a form of ex-situ conservation which involves keeping valuable animal species, especially wild animals alive outside their natural environment for educational, research and recreational purposes. South Africa is blessed with abundant wildlife species which need to be properly managed on a sustainable basis to prevent depletion. Parasites play a major role in the lives of animals, with effects ranging from negative impacts on host population size to the evolution of host behaviour to combat parasites. Gastro-intestinal tract (GIT) parasites are one of the leading factors that threaten health of wildlife, especially in captivity causing morbidity and even mortality and some are zoonotic with potential to infect staff and visitors. Currently information on GIT parasites in wildlife is scarce in South Africa, such information is important for conservation of wildlife especially in captive environments. Animals should be monitored and managed regularly, it becomes costly to treat, the parasites become resistant to drugs, and there is reduced reproduction rate in infected animals and lastly death is sometimes the end result. Although the GIT parasites at the NZG are monitored regularly through the Preventative Medicine Program, there are no scientific research studies done on this subject, let alone DNA-based studies on this subject. This study is the first of its kind at the NZG. The study investigated the seasonal distribution of GIT parasites in selected captive animals at the National Zoological Gardens of South Africa (NZG) using both microscopic and molecular techniques. A total of 772 faecal samples were collected from selected captive felids (n = 97), captive ungulates (n = 406) and captive avian species (n = 269) at the NZG between October 2015 and October 2016. Egg-floatation techniques (Faecalyser and McMaster) were used to estimate the parasite load in sampled animals whilst identity of helminth genera was confirmed by PCR. Three hundred and thirteen (40.54%) out of 772 samples were positive for one or more GIT parasites. The prevalence in ungulates was 63.55%, 39.18% in felids and 6.32% in avian species. The most commonly observed eggs via microscopy were strongyles in ungulates, Toxascaris sp. in felids and Capillaria sp. in avians with prevalence levels of 38.5%, 37.9% and 4.1% respectively. Faecal analysis revealed overall GIT parasite prevalence of 30.6%, 60.8% and 6.9% in felid, ungulate and avian species respectively over the study period. The average egg per gram (EPG) in the ungulate, felid and avian species sampled was respectively higher in warm summer months (63.7%; 47.2%; 10.8%) as compared to the colder winter months (60%; 27.3%; 1.0%). There were higher parasite loads in summer for felid avian species than in winter Warm and moist weather conditions facilitate development of parasitic eggs; hence the GIT parasite prevalence was higher in summer months. Majority of ungulates had mixed infections of strongyles type eggs. PCR detected for Haemonchus contortus in 51/107 (47.66%), 7/46 Ostertagia ostertagii (15.22%), 39/39 Trichostrongylus sp. (100%) and 13/30 Nematodirus spathiger (43.33%) from positive microscopy samples. Our study suggests that among different helminthic infections, the prevalence of nematode infections was higher than that of cestodes and trematodes. Data from this study combined with regular monitoring and treatment of captive wildlife for GIT parasites is very important for understanding and maintaining the welfare of the animals, staff and visitors at the National Zoological Gardens of South Africa