Genetic characterization of Strongyloides spp. from captive, semi-captive and wild Bornean orangutans (Pongo pygmaeus) in Central and East Kalimantan, Borneo, Indonesia

摘要

Orangutans (Pongo spp.), Asia’s only great apes, are threatened in their survival due to habitat loss, hunting and infections.\udNematodes of the genus Strongyloides may represent a severe cause of death in wild and captive individuals. In order to\udbetter understand which Strongyloides species/subspecies infect orangutans under different conditions, larvae were isolated\udfrom fecal material collected in Indonesia from 9 captive, 2 semi-captive and 9 wild individuals, 18 captive groups of\udBornean orangutans and from 1 human working with wild orangutans. Genotyping was done at the genomic rDNA locus\ud(part of the 18S rRNA gene and internal transcribed spacer 1, ITS1) by sequencing amplicons. Thirty isolates, including\udthe one from the human, could be identified as S. fuelleborni fuelleborni with 18S rRNA gene identities of 98·5–100%, with a\udcorresponding published sequence. The ITS1 sequences could be determined for 17 of these isolates revealing a huge\udvariability and 2 main clusters without obvious pattern with regard to attributes of the hosts. The ITS1 amplicons of\ud2 isolates were cloned and sequenced, revealing considerable variability indicative of mixed infections. One isolate from a\udcaptive individual was identified as S. stercoralis (18S rRNA) and showed 99% identity (ITS1) with S. stercoralis sequences\udfrom geographically distinct locations and host species. The findings are significant with regard to the zoonotic nature of\udthese parasites and might contribute to the conservation of remaining orangutan populations.