Figure 3

Model for the possible influence of pets and siblings on infant gut microbiota and subsequent development of atopic disease. Household pets (D, dogs; C, cats) and siblings increase infant exposure to environmental microbes, promoting enrichment for distinct combinations of organisms within the gut microbiota; overall richness and diversity are also impacted. Despite favoring different microbiota profiles, the net effect of both pets and siblings is to promote healthy immune system development and protect against atopic disease. Further research is required to characterize the underlying biological mechanisms.