Prevalence and genetic diversity of intestinal parasites in Xilingol League herbivores, Inner Mongolia, Northern China

Intestinal parasites are common infectious agents that substantially impact the health and productivity of livestock, with several species posing zoonotic risks. In this study, 205 fecal samples were collected from cattle, sheep, and goats in Xilingol League. Microscopic examination was performed to detect <i>Eimeria</i> spp., nematodes, and trematodes, whereas nested polymerase chain reaction assays were used to identify <i>Giardia duodenalis</i>, <i>Cryptosporidium</i> spp., and <i>Enterocytozoon bieneusi</i>. The results showed that the overall prevalence of intestinal parasites was 80.5% (165/205) among herbivores, with a co-infection rate of 47.8% (98/205). Across host species, the prevalence rates were 92.8% (126/139) in sheep, 75.0% (12/16) in goats, and 52.0% (26/50) in cattle. The prevalences of <i>Eimeria</i> spp., nematodes, trematodes, <i>G. duodenalis</i>, <i>Cryptosporidium</i> spp., and <i>E. bieneusi</i> were 59.5%, 16.1%, 33.7%, 25.9%, 7.8%, and 4.9%, respectively. Genetic characterization further revealed distinct dominant lineages, including <i>G. duodenalis</i> (assemblages B and E), <i>Cryptosporidium</i> spp. (<i>C. andersoni</i> and <i>C. xiaoi</i>), and <i>E. bieneusi</i> (genotypes J and BEB6). Furthermore, infection with <i>Eimeria</i> spp. was significantly associated with an increased likelihood of co-infection with other intestinal parasites. Together, these findings provide a comprehensive overview of intestinal parasite co-infections among herbivores in Xilingol League and highlight pronounced interspecies differences and regional variation in parasite distribution.IMPORTANCEIntestinal parasitic infections remain a major constraint for animal health and productivity, especially in large-scale grassland livestock systems. Despite their economic and zoonotic implications, comprehensive assessments of intestinal parasite co-infection patterns in these ecosystems have been lacking. This study addresses this gap by characterizing the prevalence, diversity, and genetic makeup of key intestinal parasites in Xilingol League. The detection of frequent co-infections and predominant zoonotic genotypes underscores the importance of integrated parasite management strategies. Furthermore, infection with <i>Eimeria</i> spp. was significantly associated with co-infections involving other intestinal parasites, suggesting potential interactions that require further investigation. These insights are critical for informing region-specific parasite control measures, improving veterinary health outcomes, and reducing potential public health threats at the livestock-human interface.