No abstract

S U M M A R YOrangutans (Pongo spp.), Asia's only great apes, are threatened in their survival due to habitat loss, hunting and infections. Nematodes of the genus Strongyloides may represent a severe cause of death in wild and captive individuals. In order to better understand which Strongyloides species/subspecies infect orangutans under different conditions, larvae were isolated from fecal material collected in Indonesia from 9 captive, 2 semi-captive and 9 wild individuals, 18 captive groups of Bornean orangutans and from 1 human working with wild orangutans. Genotyping was done at the genomic rDNA locus (part of the 18S rRNA gene and internal transcribed spacer 1, ITS1) by sequencing amplicons. Thirty isolates, including the one from the human, could be identified as S. fuelleborni fuelleborni with 18S rRNA gene identities of 98·5-100%, with a corresponding published sequence. The ITS1 sequences could be determined for 17 of these isolates revealing a huge variability and 2 main clusters without obvious pattern with regard to attributes of the hosts. The ITS1 amplicons of 2 isolates were cloned and sequenced, revealing considerable variability indicative of mixed infections. One isolate from a captive individual was identified as S. stercoralis (18S rRNA) and showed 99% identity (ITS1) with S. stercoralis sequences from geographically distinct locations and host species. The findings are significant with regard to the zoonotic nature of these parasites and might contribute to the conservation of remaining orangutan populations.

S U M M A R YFaecal samples from 163 captive and semi-captive individuals, 61 samples from wild individuals and 38 samples from captive groups of Bornean orangutans (Pongo pygmaeus) in Kalimantan, Indonesia, were collected during one rainy season (November 2005-May 2006 and screened for intestinal parasites using sodium acetate-acetic acid-formalin-concentration (SAFC), sedimentation, flotation, McMaster-and Baermann techniques. We aimed to identify factors influencing infection risk for specific intestinal parasites in wild orangutans and individuals living in captivity. Various genera of Protozoa (including Entamoeba, Endolimax, Iodamoeba, Balantidium, Giardia and Blastocystis), nematodes (such as Strongyloides, Trichuris, Ascaris, Enterobius, Trichostrongylus and hookworms) and one trematode (a dicrocoeliid) were identified. For the first time, the cestode Hymenolepis was detected in orangutans. Highest prevalences were found for Strongyloides (individuals 37% ; groups 58 %), hookworms (41 % ; 58 %), Balantidium (40 % ; 61 %), Entamoeba coli (29 %; 53 %) and a trichostrongylid (13 %; 32 %). In re-introduction centres, infants were at higher risk of infection with Strongyloides than adults. Infection risk for hookworms was significantly higher in wild males compared with females. In groups, the centres themselves had a significant influence on the infection risk for Balantidium. Ranging patterns of wild orangutans, overcrowding in captivity and a shift of age composition in favour of immatures seemed to be the most likely factors leading to these results.