Some dogs carry a mixed bag of influenza viruses. The discovery raises the possibility that dogs may be able to pass the flu to people, perhaps setting off a pandemic.
That mixing generates genetic diversity in the viruses that makes them potentially a pandemic threat.
Study coauthor Adolfo García-Sastre, a virologist who directs the Global Health and Emerging Pathogens Institute of the Icahn School of Medicine at Mount Sinai in New York City says, evolution of the flu viruses in dogs has been very rapid, occurring in just a few years, García-Sastre says. There’s no sign yet that the dog flu viruses can infect people, but that could change. “The more diversity of viruses there is in an animal reservoir, the higher the chances that it will lead to a version of the virus that is able to jump” to humans, he says.
For mixing up the next human pandemic influenza virus pigs and birds remain the prime suspects, says Amesh Adalja, an infectious disease physician at Johns Hopkins University and a spokesperson for the Infectious Diseases Society of America.
Even if a dog flu virus infected a person, the pathogen may not be able to transmit easily from person-to-person — an important characteristic a virus must have before it can circulate around the world.
In pigs, the viruses swapped genes among themselves, creating new varieties, some of which were passed to dogs. A virus genetically similar to one of the swine viruses passed to dogs was found in a person in China, raising the possibility that some swine flus can strike both pups and people.
He says, “knowing that dogs could contribute is important for preparing for the next pandemic, because we don’t know exactly what that virus will be.”