18S rDNA next-generation sequencing uncovers the biodiversity of Gastrointestinal parasites in Tibetan grazing ruminants in China.

Abstract

BACKGROUND: Free-range yak, Tibetan sheep and Tibetan goat, predominantly distributed across the Qinghai-Tibetan Plateau (QTP) in China, are highly susceptible to a wide range of parasite infections, resulting in underestimated economic losses. We aimed to investigate the biodiversity of gastrointestinal parasites in local ruminants based on 18 S SSU ribosomal DNA gene (18 S rDNA) using next-generation sequencing. METHODS: Following DNA extraction from 79 fecal samples collected from yak, Tibetan sheep and goat in the southeast part of QTP, we proceeded to amplify the V3-V4 fragments of the18S rDNA gene. Subsequently, we assessed the diversity of parasitic protozoa and helminths. To identify parasitic infection patterns, correlation studies were conducted in different factors, including ages, health conditions and seasons. RESULTS: A total of 192 operational taxonomic units (OTU) were identified, including 10 phyla and 27 genera. High prevalence was observed in(93.67%),(75.95%) and(68.35%). By phylogenetic analysis, we identified a potential newspecies, along with zoonotic species/subtypes, such asandST10, ST12, and ST14. Two rarely reported zoonotic protozoa,and, were particularly noted for their high prevalence of infection and potential association with diarrhea. Juveniles and adults shared the similar species of parasites. A significant reduction in helminth diversity and infection prevalence was documented during autumn. CONCLUSIONS: This study provides critical insights into the diversity of gastrointestinal parasites in QTP ruminants, thereby enhancing our understanding of the infection risk in grazing livestock. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12917-025-04887-6.