A new study funded by the National Institute of Allergy and Infectious Diseases (NIAID) reveals risks of asthma and allergies are greatly reduced if an infant child lives in a home with a dog present. This new research was published in the Proceedings of the National Academy of Sciences (PNAS), and involves groups of researchers from UC San Francisco, the University of Michigan, Henry Ford Health System and Georgia Regents University. The scientists concluded that the gastrointestinal microbiome in mice (the bacteria present in the gut of the mouse) is restructured to become less sensitive to common allergens if they have been exposure to the dust created by a dog inhabiting a home. The scientists arrived at this conclusion by subjecting mice to certain allergens after the mice had been exposed to dust a dog created when encouraged to roam inside, as well as outside of the home. While looking at mice that were exposed to cockroach or protein allergens, they discovered that asthma-like reactions were greatly reduced in those that had been previously exposed to the dog-dust. They learned that not only was the asthmatic response significantly reduced, but that this improved community of microbes protected the mice’s airways against allergies and viral respiratory infections as well.
According to the researchers, these results are likely to explain the reduced allergy risk among children similarly exposed to this type of dust when raised amongst dogs from birth. In addition, the study points out that the shielding of air passages by way of dog created dust exposure reduces the number and strength of asthma-linked immune cells. In fact, when the isolated bacterial species, lactobacillus johnsonii was given to mice, it was found that it could prevent the respiratory syncytial virus (RSV) infection, which is directly linked to elevated asthma risks in infant children. This and other friendly bacteria may soon be used to reshape the gut microbiome to prevent asthma and allergies, and possibly even treat existing cases. Current studies are underway using humans that show great promise for new lung infection and allergic airway disease therapies. The findings are indicative of the vast effects gut microbiome can have not only in the intestinal track, but on the entire immune system.