Giardia Duodenalis Colonization Slightly Affects Gut Microbiota And Haematological Parameters In Clinically Healthy Dogs

Giardia duodenalis ( G. duodenalis ) is a worldwide cause of acute diarrheal disease both in humans and in animals. Domestic dogs may either harbor the parasite subclinically or showing the infection typical clinical signs. However, because giardiosis is a recognized veterinary threat, testing for this agent is often performed when canine patients are presented to veterinarians. Usually, animals are treated with antiparasitic agents in case of positive test, regardless of the severity of enteric clinical signs. Here we report for the first time a study comparing two groups of clinically healthy German shepherd dogs differing for G. duodenalis colonization. Gut microbiota, the haematological, biochemical and faecal parameters related to the intestinal function were investigated. The results display a scenario in which G. duodenalis exerts an effect upon the gut microbiota affecting the proportion of few bacterial taxa known to be associated with improved lipids metabolism and protection from gut inflammation. This also suggest that the antiparasitic treatments that are usually administered to G. duodenalis positive dogs might be avoided in clinically healthy subjects, since the presence of G. duodenalis does not substantially modify the microbial ecology of the intestinal lumen nor the haematological markers of disease.