Molecular Epidemiology of Blastocystis in Confined Slow Lorises, Macaques, and Gibbons

SIMPLE SUMMARY: Blastocystis sp. is one of the most frequently reported parasites and an intestinal anaerobic organism with high genetic diversity, which seriously threatens the health of non-human primates (NHPs). We conducted a comparative study based on small subunit ribosomal RNA (SSU rRNA) to assess the Blastocystis infection, its gene subtypes, and its zoonotic potential in confined macaques, gibbons, and slow lorises. The results indicated that the Blastocystis infections significantly differed between seasons and species. This is the first report on the prevalence and subtype distribution of Blastocystis sp. among captive slow lorises (Nycticebus spp.). The findings may contribute to formulating a feasible strategy for the improved confined management of NHPs and subsequent conservation practices, such as soft release. ABSTRACT: Blastocystis sp. is a common intestinal anaerobic parasite infecting non-human primates and many other animals. This taxon threatens the health of NHPs due to its high genetic diversity, impeding efforts to improve confined management and subsequent conservation practices. This study collected 100 and 154 fecal samples from captive macaques, gibbons, and slow lorises in the summer and winter, respectively. The Blastocystis infection, its gene subtypes, and its zoonotic potential based on small subunit ribosomal RNA (SSU rRNA) were analyzed. The prevalence of Blastocystis in the three primate genera was 57.79% (89/154) in the summer (2021) and 29.00% (29/100) in the winter (2020). Four zoonotic subtypes—ST1, ST2, ST3, and ST4—were identified. ST2 was the most prevalent subtype, suggesting that these animals may serve as reservoirs for pathogens of human Blastocystis infections. The macaques showed a more significant variation in Blastocystis infection between seasons than gibbons and slow lorises. The slow lorises in small cages and enclosure areas were potentially more infected by Blastocystis in the summer, indicating that inappropriate captive management may have detrimental effects on their health.