Prevalence of <i>Cryptosporidium</i> spp., <i>Enterocytozoon bieneusi</i>, <i>Encephalitozoon</i> spp. and <i>Giardia intestinalis</i> in Wild, Semi-Wild and Captive Orangutans (<i>Pongo abelii</i> and <i>Pongo pygmaeus</i>) on Sumatra and Borneo, Indonesia

<div><p>Background</p><p>Orangutans are critically endangered primarily due to loss and fragmentation of their natural habitat. This could bring them into closer contact with humans and increase the risk of zoonotic pathogen transmission.</p><p>Aims</p><p>To describe the prevalence and diversity of <i>Cryptosporidium</i> spp., microsporidia and <i>Giardia intestinalis</i> in orangutans at seven sites on Sumatra and Kalimantan, and to evaluate the impact of orangutans’ habituation and location on the occurrence of these zoonotic protists.</p><p>Result</p><p>The overall prevalence of parasites in 298 examined animals was 11.1%. The most prevalent microsporidia was <i>Encephalitozoon cuniculi</i> genotype II, found in 21 animals (7.0%). <i>Enterocytozoon bieneusi</i> genotype D (n = 5) and novel genotype Pongo 2 were detected only in six individuals (2.0%). To the best of our knowledge, this is the first report of these parasites in orangutans. Eight animals were positive for <i>Cryptosporidium</i> spp. (2.7%), including <i>C</i>. <i>parvum</i> (n = 2) and <i>C</i>. <i>muris</i> (n = 6). <i>Giardia intestinalis</i> assemblage B, subtype MB6, was identified in a single individual. While no significant differences between the different human contact level groups (<i>p</i> = 0.479–0.670) or between the different islands (<i>p</i> = 0.992) were reported in case of <i>E</i>. <i>bieneusi</i> or <i>E</i>. <i>cuniculi</i>, <i>Cryptosporidium</i> spp. was significantly less frequently detected in wild individuals (<i>p</i> < 2×10⁻¹⁶) and was significantly more prevalent in orangutans on Kalimantan than on Sumatra (<i>p</i> < 2×10⁻¹⁶).</p><p>Conclusion</p><p>Our results revealed that wild orangutans are significantly less frequently infected by <i>Cryptosporidium</i> spp. than captive and semi-wild animals. In addition, this parasite was more frequently detected at localities on Kalimantan. In contrast, we did not detect any significant difference in the prevalence of microsporidia between the studied groups of animals. The sources and transmission modes of infections were not determined, as this would require repeated sampling of individuals, examination of water sources, and sampling of humans and animals sharing the habitat with orangutans.</p></div

Geographical distribution of <i>Pongo abelii</i> and <i>Pongo pygmaeus</i> on Sumatra and Kalimantan, respectively, with sampling areas highlighted.

<p>Geographical distribution of <i>Pongo abelii</i> and <i>Pongo pygmaeus</i> on Sumatra and Kalimantan, respectively, with sampling areas highlighted.</p

Maximum-likelihood tree of whole ITS region of <i>Enterocytozoon bieneusi</i>.

<p>Sequences generated in this study are shaded. Taxa previously found in non-human primates are bolded. The tree with the highest log likelihood is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. Only bootstrap values >50% are shown. Scale bar included in each tree.</p

Maximum-likelihood tree of partial sequences of small ribosomal subunit (SSU) gene of <i>Cryptosporidium</i> spp. Sequences generated in this study are shaded.

<p>Taxa previously found in non-human primates are bolded. The tree with the highest log likelihood is shown. The percentage of trees in which the associated taxa clustered together is shown next to the branches. Only bootstrap values >50% are shown. Scale bar included in each tree.</p