The hypothesis was announced at the General Meeting of the American Society for Microbiology. Having already proven that the microbiome of dust from homes that have pets is distinct from dust in pet-free homes, the biologists decided to find out if this knowledge had any practical applications.

After exposing mice to dust from homes that have dogs, then to the respiratory syncytial virus (RSV) — a virus common in infants and associated with a high risk of developing asthma in childhood — the team found that the mice were immune to the virus. The biologists used three test groups in the study — mice exposed to RSV, mice exposed to RSV and house dust and mice exposed to neither.

“Mice fed dust did not exhibit symptoms associated with RSV-mediated airway infection, such as inflammation and mucus production,” said Kei Fujimura, a member of the research team. “They also possessed a distinct gastrointestinal bacterial composition compared to animals not fed dust”.

This suggests that the mice microbiome is permanently altered after exposure, and possibly the mice immune system as a result.

The theory is, according to Fujimura, that, “microbes within dog-associated house dust may colonise the gastrointestinal tract, modulate immune responses and protect the host against the asthmagenic pathogen RSV”.

The next step, said Fujimura, is to identify exactly which microbial species is responsible for this protection against RSV, and whether the defence system is a result of animal-derived microbes or a more diverse combination of bacteria. The team has already analysed the microbiome of house pet intestines, so are on their way to answering this question.

The hope is that by identifying the microbe we can improve our knowledge of allergic diseases, and even develop vaccines for respiratory viruses.

The research has not yet gone through peer review.

Source: Wired UK