Effects of Gasterophilus pecorum infestation on the intestinal microbiota of the rewilded Przewalski's horses in China.
Authors: Hu Dini, Chao Yuzhu, Zhang Boru, Wang Chen, Qi Yingjie, Ente Make, Zhang Dong, Li Kai, Mok Kai Meng
Journal: PloS one
Summary
Gasterophilus pecorum larvae colonising the equine intestine for extended periods risk disrupting the microbial ecosystem, yet this phenomenon had never been characterised in the critically endangered Przewalski's horses reintroduced to China's Kalamaili Nature Reserve. Researchers profiled the faecal microbiota of seven severely infested animals before and after anthelmintic treatment using 16S rRNA gene sequencing, comparing bacterial community structure between parasitised and parasite-free states. Heavy G. pecorum infestation significantly increased microbial richness without enhancing diversity, whilst markedly skewing the Firmicutes-to-Bacteroidetes ratio downwards by over 50% — a concerning shift associated with digestive dysfunction — and substantially reducing beneficial genera including Streptococcus, Lactobacillus and Bifidobacterium. The depletion of these symbiotic bacteria, which support gut immunity and parasite resistance, suggests that botfly larvae exert measurable harm beyond mechanical intestinal damage, compromising microbial-mediated host defences. For practitioners managing equines in botfly-endemic regions or dealing with chronic parasitic burdens, these findings reinforce the importance of timely anthelmintic intervention and highlight a previously unquantified mechanism through which parasite control directly restores intestinal health.
Read the full abstract on PubMed
Practical Takeaways
- •Gasterophilus pecorum infestation causes significant dysbiosis in horses, potentially increasing colic risk and digestive dysfunction despite normal microbial diversity indicators
- •Monitor for microbial imbalances (low beneficial bacteria) in heavily parasitized horses; probiotic support may be warranted alongside anthelmintic treatment
- •Effective parasite control is essential to maintain healthy intestinal microbiota and immune function in grazing horses
Key Findings
- •G. pecorum infestation significantly increased intestinal microbial richness but not diversity in rewilded Przewalski's horses
- •Parasitic infestation decreased the Firmicutes/Bacteroidetes ratio by over 50%
- •Severe reduction in Streptococcus and Lactobacillus abundance with infestation suggested increased colic and digestion risk
- •Decreased symbiotic genera (Lactobacillus and Bifidobacterium) with infestation may reduce immunity against parasitic infection