According to newly-published research, human norovirus may infect dogs. The study was published in the American Society for Microbiology’s Journal of Clinical Microbiology.

The study’s first author was Sarah Caddy, VetMB, PhD, MRCVS, a veterinarian and PhD student at the University of Cambridge, and Imperial College, London. Norovirus causes most of the food-borne diseases in the US, according to the Centers for Disease Control and Prevention (CDC).

The research showed that some dogs’ immune systems could respond and defend against the human norovirus. Caddy said, “This strongly suggests that these dogs have been infected with the virus. We also confirmed that that human norovirus can bind to the cells of the canine gut, which is the first step required for infection of cells.”

The researchers performed latter research with non-infectious human norovirus, but Caddy said that it is not yet clear how much canine transmission and infection could be a problem for humans. Despite the apparent susceptibility of dogs to the virus, investigators could not find signs of the virus in canine stool samples, even for those dogs that had diarrhea. They did find the virus in serum samples of around 14.28 percent of the 325 dogs tested in total.

It is also not yet clear whether the virus could cause a clinical illness in dogs, and whether dogs themselves could spread the virus to infect humans. Clinical investigators have estimated that 18 virus particles can cause an infection in humans.

Caddy said, “As a small animal veterinarian, I am often asked by dog owners if they might be able to pass infections onto their dogs, or if their dogs are contagious to them. There are plenty of anecdotal cases of dogs and humans in the same household, having simultaneous gastroenteritis, but very little rigorous scientific research is conducted in this area.”

She concluded, “Until more definitive data is available, sensible hygiene precautions should be taken around pets, especially when gastroenteritis in either humans or dogs is present in a household.”