The microbes living on your pet dog may help to strengthen your immune system and prevent childhood asthma, according to a new study.
It is known that infants with severe cases of respiratory syncytial virus (RSV) have an increased chance of developing asthma. This latest study shows bacteria found in the dust of homes with dogs may have protective effects against RSV.
"These findings are the first step towards creating a therapy to protect infants against RSV and therefore lessening the occurrence of asthma in the long term," says Dr Kei Fujimura, a molecular biologist at the University of California, San Francisco and who presented his group's work at the 112th General Meeting of the American Society for Microbiology.
Previous studies have shown that bacterial communities in house dust are different in homes with and without dogs, and that children living with pet dogs have a lower incidence of asthma.
To see if there is a link, scientists collected dust from homes with dogs, mixed it in a solution and fed it to mice. After eight days, these animals were given RSV. Their immune response was compared to another group infected with RSV, and a control group of healthy mice.
The mice that were fed house dust did not develop the inflammation and mucous production symptomatic of RSV. A different group of bacteria were also found in the gastrointestinal tract of these mice compared to the other experimental groups.
"In this experiment we were able to manipulate the gut micro biota and this influenced the immune response in the lungs," says Fujimura.
She says that this distinct set of gut micro biota helped protect the mice from developing RSV. However, the team is not sure exactly which bacteria are the key drivers for this response.
Fujimura says these results support the hypothesis that exposure to animals in early childhood stimulates the immune system to resist the development of asthma and other allergies.
Professor Suresh Mahalingam, a virologist at Griffith University in Brisbane, says that this is an important area of research as RSV affects 90 per cent of children worldwide.
"Whether this experiment has relevance to humans, no one has yet shown," he says. "The way forward now is to carry out some population-based studies to see if there's a correlation between reduced RSV infection among children living in the presence of dogs."