A UCSF-led study found that a child’s risk for developing allergies and asthma is reduced when they are exposed in early infancy to a dog in the household. It has to do with the type of dust indoor/outdoor dogs carry in.
The results were obtained in studies of mice challenged with allergens after earlier exposure to dust from homes with dogs, but the results also are likely to explain the reduced allergy risk among children raised with dogs from birth.
The scientists also identified a specific bacterial species (Lactobacillus johnsonii) within the gut that is critical to protecting the airways against both allergens and viral respiratory infection. When they fed this bacteria alone to mice, they found it could prevent airway inflammation due to allergens or even respiratory syncytial virus (RSV) infection. Severe RSV infection in infancy is associated with elevated asthma risk.