Children who live with dogs have a decreased risk for asthma due to an exposure to a unique collection of microbes found within dog-associated house dust, says a new asthma study presented at the 2012 General Meeting of the American Society for Microbiology.
Researchers have long known that children who share a home with household pets tend to have a decreased risk for asthma compared to children living without a furry friend. According to a new study conducted by researchers at the University of California, San Francisco, house dust containing protective factors against a common respiratory virus associated with the development of asthma in children, respiratory syncytial virus (RSV), appears to lower the risk for asthma.
As Kei Fujimura, a researchers from the Colitis and Crohn’s Disease Center of the Division of Gastroenterology at University of California, San Francisco, California and one of the researchers of the study, comments:
“In this study we found that feeding mice house dust from homes that have dogs present protected them against a childhood airway infectious agent, respiratory syncytial virus (RSV). RSV infection is common in infants and can manifest as mild to severe respiratory symptoms. Severe infection in infancy is associated with a higher risk of developing childhood asthma.”
To determine a link, if any, between pet ownership and a decreased risk for asthma, the researchers compared the house dust from homes with a dog to homes without pets by comparing three groups of mice: (1) Mice fed house dust from homes with dogs before being infected with RSV, (2) mice infected with RSV without exposure to dog-associated house dust, and (3) a control group of mice not infected with RSV.
The mice who were fed the dog-associated house dust were protected against severe RSV infections, which in turn decreased the risk for asthma. As Fujimura comments:
“Mice fed dust did not exhibit symptoms associated with RSV-mediated airway infection, such as inflammation and mucus production. They also possessed a distinct gastrointestinal bacterial composition compared to animals not fed dust.”
In other words, the unique microbial composition of house dust in homes with pet dogs appears to offer protection against RSV during infancy, thus lowering the risk for asthma later in the life.
As Fujimura explains:
“This [The findings of a previous study] led us to speculate that microbes within dog-associated house dust may colonize the gastrointestinal tract, modulate immune responses and protect the host against the asthmagenic pathogen RSV. This study represents the first step towards determining the identity of the microbial species which confer protection against this respiratory pathogen.”
According to the American Lung Association, asthma is a chronic and serious respiratory disease that affects approximately 17 million Americans. With an estimated 1.81 million individuals with asthma requiring treatment in emergency rooms for asthma symptoms and approximately 500,000 individuals requiring hospitalization for asthma-related problems, the cost for treating the disease in the United States is around $19.7 billion each year. No cure currently exists for asthma.
The results of the present study are important for the future of asthma research. The findings may help to develop treatments for RSV, which may decrease the risk for asthma among children.
Would you adopt a pet dog to help lower your child’s risk for asthma?