Association of Giardia intestinalis Infection with Intestinal Fungal Dysbiosis in Xizang Yaks

Yak is an important bovine ruminant; however, little is known about fungal microbiota shifts in Giardia (G.) intestinalis infected yaks in Xizang.Therefore, we compared the fecal fungal microbiota of G. intestinalis positive (GD) and G. intestinalis negative (CG) yaks from Lhünzhub County, Xizang, China, using ITS amplicon sequencing.A total of 83 fecal samples were collected during 2026, including 53 samples from diarrheal yaks and 30 samples from clinically healthy yaks.Following parasite detection, six samples from each group (GD and CG) were selected for ITS-based molecular sequencing.A total of 890,652 filtered sequences were obtained, including 500,947 from the GD group and 389,705 from the CG group.Alpha-diversity analysis showed significantly higher ACE (P<0.01),Chao1 (P<0.01),observed species (P<0.01),Pielou evenness (P<0.001),Shannon (P<0.001), and Simpson (P<0.0001)indices in GD yaks than in CG yaks.Two phyla and 17 genera were identified as potential fungal biomarkers associated with G. intestinalis infection, including Naganishia, Aspergillus, Cleistothelebolus, Xenodidymella, Piromyces, Urocystis, Fungi gen.incertae sedis, Plenodomus, Neoascochyta, Paraphaeosphaeria, Coniochaeta, Cystobasidium, Sporormiaceae gen.incertae sedis, Sclerostagonospora, Arthrinium, Neosetophoma, and Leucosporidium.These findings provide preliminary insights into alterations in the fecal fungal microbiota associated with G. intestinalis infection in yaks on the Xizang Plateau.