Homes with dogs provide infants with protection against allergies and asthma

dogs help children not develop allergies

Infants who live with dogs during their first year of life are less likely to develop allergies and asthma. This fact has been recognized by medical circles for some time, but until this week, the reasons were less clear.

Researchers from the University of California in San Francisco, announced they may have discovered the reason why – house dust.

House dust from homes with dogs appears to protect against infection of a common respiratory virus that is associated with the development of asthma in children.

In their experiments, they found that exposing mice to house dust that had come from a home with a dog protected the the mice from respiratory syncytial virus (RSV). RSV can cause mild to severe respiratory symptoms. Severe infections of RSV tend to lead to a higher risk of a child developing childhood asthma.

Kei Fujimura, a researcher on the study said she and her colleagues compared three groups of mice: mice living with house dust from homes with dogs before being infected with RSV, mice infected with RSV without exposure to dust and a control group of mice not infected with RSV.

The mice exposed to the dog dust, not only did not develop symptoms of RSV after exposure, they also "possessed a distinct gastrointestinal bacterial composition" says Fujimura.

The collection of bacterial communities (the microbiome) in mice living with house dust from homes that have a cat or dog is different from house dust from homes with no pets. Therefore, the scientists speculated that protective microbes may colonize in an infant’s gastrointestinal tract, providing immunity against the asthmatic pathogen.

"This study represents the first step towards determining the identity of the microbial species which confer protection against this respiratory pathogen," says Fujimura.

The identification of the helpful microbes will be a crucial step towards understanding the role they play in thwarting allergies and asthma. Eventually, it is hoped that microbial-based therapies could be developed to protect against RSV and ultimately reduce the risk of childhood asthma.

These findings were presented during the 2012 General Meeting of the American Society for Microbiology, the largest conference for scientists working in the field of infectious disease.