Comparative cross-sectional survey on gastrointestinal parasites of captive, semi-captive, and wild Elephants of Sri Lanka

Abstract

Parasites can influence the fitness of individuals particularly of small populations of endangered species.  An island-wide, cross sectional, coprological survey was carried out from 03 January to 30 October 2015, to determine the gastrointestinal (GI) parasites of the Sri Lankan Elephant Elephas maximus maximus.  Fresh fecal samples from wild, captive and semi-captive elephants were collected and analyzed using a modified salt floatation, Sheather’s sucrose floatation, direct iodine smears, and sedimentation methods. Species identification was done morphologically. Intensity of parasite infections was determined using McMaster technique.  A total of 85 fecal samples (wild = 45, semi-captive = 20, captive = 20) were analysed; 58 (68.2%) samples were positive for GI parasites.  Overall, helminth infections (60.0%) were more common than protozoan (37.6%) infections (Chi square test, χ2 = 8.499; p < 0.001). In the captive elephants, however, more protozoan infections were observed than helminthes, which could be due to anthelminthic treatment.  A significantly higher prevalence of infection was observed in the wild elephants (93.3%) compared to semi-captive elephants (55.0%; χ2 = 13.516; p < 0.001) and captive elephants (25.0%; χ2 =32.289; p < 0.001) but there was no significant difference in the prevalence between captive and semi-captive elephants (χ2 =3.750; p = 0.053).  Ten types of GI parasites were observed, nine of which were recorded in wild elephants.  Among them the most common infection was strongyles (34.1%) with high intensity (440.1±295.2 EPG).  Semi-captive elephants harbored five types of GI parasites, while captive elephants had only three types.  One captive elephant at the Temple of the Tooth was infected with the tapeworm Anoplocephala sp. at low intensity of 50 EPG.  Some of the GI parasites recorded are highly pathogenic while others are incidental.