Dogs can be infected with noroviruses, including strains closely related to the human “stomach flu” virus, but this appears to be uncommon and usually causes milder illness in dogs than in people.

What norovirus does in dogs

Norovirus is a contagious gastrointestinal virus that can cause vomiting, diarrhea, lethargy, and dehydration in dogs, similar to people. Studies have identified norovirus in dogs with diarrhea, and some outbreaks in kennels and household settings have been linked to norovirus infection.

Human–dog transmission

Research has shown that human norovirus can bind to cells in the canine gut and that some pet dogs have antibodies against human norovirus, meaning they have been exposed and likely infected. In a few household and kennel studies, dogs living with people who had norovirus tested positive for human norovirus, suggesting it can sometimes pass from humans to dogs (and possibly vice versa), although this route is still being studied.

How worried you should be

Available evidence suggests most infected dogs either have mild signs (vomiting, soft stool, decreased appetite) or no obvious illness at all, and severe disease from norovirus alone appears rare in otherwise healthy adult dogs. The bigger concern is that dogs might act as temporary carriers of human norovirus on or in their bodies, potentially contributing to spread in households, which is why good hygiene is important if anyone has stomach flu symptoms.

What to do if your dog is sick

Contact a veterinarian promptly if your dog has repeated vomiting, diarrhea lasting more than a day, blood in stool or vomit, or signs of dehydration (dry gums, sunken eyes, weakness). Clean up vomit and feces with gloves and disinfect hard surfaces with an appropriate cleaner, wash hands thoroughly, and keep young children, elderly people, and immunocompromised individuals away from the sick dog’s waste until everyone is well.