Molecular survey of Blastocystis sp. from humans and associated animals in an Indonesian community with poor hygiene.

Blastocystis sp. is a common parasite found in human and animal fecal samples. Currently, human Blastocystis isolates are classified into nine subtypes (STs) based on the phylogeny of their small subunit ribosomal RNA genes (SSU rDNAs). Since eight of the nine STs, except for ST9, have been reported in both humans and animals, these parasites are considered to be potentially zoonotic STs. To evaluate whether zoonotic transmissions play a main role in the lifecycle of Blastocystis, STs derived from humans, domestic pigs, domestic chickens, and wild rodents in a community with poor hygiene in Sumba Island, Indonesia were surveyed. Although fecal cross-contaminations between humans and animals were likely common at the investigation site, the confirmed major Blastocystis STs, which were detected as intense bands on gels following PCR targeting of the SSU rDNA, were different in each host species. STs 1-3 were found in resident children, while ST5, ST7, and ST4 were found in domestic pigs and chickens, and in wild rodents, respectively. Faint bands of STs 1, 2, and 7 were detected in samples from pigs, while no minor STs were observed in samples from the other host species. The distinct distributions of the major STs among the host animals examined, including humans, indicate host specificity in the lifecycle of Blastocystis. Considering the coprophagous nature of pigs, the presence of minor STs observed only in pigs could be explained by the mechanical passage of contaminated fecal materials.

Molecular characterization of various trichomonad species isolated from humans and related mammals in Indonesia.

Trichomonad species inhabit a variety of vertebrate hosts; however, their potential zoonotic transmission has not been clearly addressed, especially with regard to human infection. Twenty-one strains of trichomonads isolated from humans (5 isolates), pigs (6 isolates), rodents (6 isolates), a water buffalo (1 isolate), a cow (1 isolate), a goat (1 isolate), and a dog (1 isolate) were collected in Indonesia and molecularly characterized. The DNA sequences of the partial 18S small subunit ribosomal RNA (rRNA) gene or 5.8S rRNA gene locus with its flanking regions (internal transcribed spacer region, ITS1 and ITS2) were identified in various trichomonads; Simplicimonas sp., Hexamastix mitis, and Hypotrichomonas sp. from rodents, and Tetratrichomonas sp. and Trichomonas sp. from pigs. All of these species were not detected in humans, whereas Pentatrichomonas hominis was identified in humans, pigs, the dog, the water buffalo, the cow, and the goat. Even when using the high-resolution gene locus of the ITS regions, all P. hominis strains were genetically identical; thus zoonotic transmission between humans and these closely related mammals may be occurring in the area investigated. The detection of Simplicimonas sp. in rodents (Rattus exulans) and P. hominis in water buffalo in this study revealed newly recognized host adaptations and suggested the existence of remaining unrevealed ranges of hosts in the trichomonad species.