Molecular characterization and zoonotic potential of

Blastocystis is one of the most prevalent intestinal protozoans, transmitted through the fecal-oral route. Domestic pigs and cattle serve as important reservoirs for Blastocystis, playing a crucial role in its transmission dynamics. In the present study, a PCR-sequencing tool based on the small subunit ribosomal RNA (SSU rRNA) gene was employed to investigate the prevalence and subtypes of Blastocystis in 456 pig and 302 cattle fecal samples collected in Hainan, the only tropical island province in China. The overall prevalence of Blastocystis in pigs and cattle was 30.3% (138/456) and 13.2% (40/302), respectively. Six known subtypes-ST5 (n = 139), ST21 (n = 18), ST26 (n = 10), ST10 (n = 7), ST23 (n = 2), and ST25 (n = 2)-were identified, including 138 ST5 from pigs, and 18 ST21, 10 ST26, 7 ST10, 2 ST23, 2 ST25, and 1 ST5 from cattle. A novel ST5 sequence (OQ048307) from a pig and a novel ST10 sequence (OQ048308) from a cow were detected. Our results suggest that livestock may be an important potential reservoir for zoonotic Blastocystis infection in humans and provided reliable data for future research on subtype distribution and infection control of this protozoan in tropical regions.