Prevalence and molecular characterization of Giardia intestinalis in racehorses from the Sichuan province of southwestern China.
Authors: Deng Lei, Li Wei, Zhong Zhijun, Liu Xuehan, Chai Yijun, Luo Xue, Song Yuan, Wang Wuyou, Gong Chao, Huang Xiangming, Hu Yanchun, Fu Hualin, He Min, Wang Ya, Zhang Yue, Wu Kongju, Cao Suizhong, Peng Guangneng
Journal: PloS one
Summary
# Editorial Summary: Giardia intestinalis in Chinese Racehorses Giardia intestinalis is a significant protozoal cause of diarrhoea in equine populations worldwide, yet prevalence data and genotyping information from China remain limited. Researchers examined 264 faecal samples from racehorses across six equestrian facilities in Sichuan province using nested PCR targeting the triose-phosphate isomerase (tpi) gene, supplemented by sequencing analysis of the gdh and bg loci to determine assemblage types and multilocus genotypes. Overall prevalence was 8.3% (22 animals), with facility-level variation ranging from 3.6% to 13.5%, and molecular characterisation revealed both zoonotic assemblages A (AIV subtype) and B (BIV subtype variants) alongside the mouse-specific assemblage G and a novel multilocus genotype B. The concurrent presence of human-transmissible and animal-adapted assemblages in these racehorses indicates they may serve as a potential zoonotic reservoir, warranting consideration of infection control measures at racing establishments and heightened awareness among personnel handling infected animals. Given that giardiasis causes both clinical disease and subclinical carriage in horses, practitioners should maintain diagnostic vigilance in cases of chronic or recurrent diarrhoea and implement appropriate biosecurity protocols to minimise transmission risk to staff, owners and other animals.
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Practical Takeaways
- •Approximately 1 in 12 racehorses in affected regions carry Giardia; diarrhea cases should prompt diagnostic testing to identify infection status
- •Racehorses with Giardia pose a zoonotic transmission risk to human handlers and facility staff, warranting enhanced biosecurity and hygiene protocols
- •Prevalence varies significantly between facilities (3.6–13.5%), suggesting management and facility-specific factors influence infection rates—review feed, water, and sanitation practices
Key Findings
- •G. intestinalis prevalence in Chinese racehorses was 8.3% (22/264), with club-level variation from 3.6% to 13.5%
- •Both potentially zoonotic assemblages A and B were identified, indicating racehorses may pose zoonotic risk to humans
- •Assemblage A isolates matched subtype AIV while assemblage B showed sequence variability within subtype BIV
- •One novel multilocus genotype (MLG2) of assemblage B was identified in this first study of G. intestinalis in Chinese racehorses