A new study conducted by researchers in Finland found that pet dogs are able to carry human strains of norovirus, a leading cause of stomach flu symptoms in people, and pass the strains on to other household members, according to a report.

The University of Helinski's Department of Food Hygiene and Environmental Health researchers looked at 92 fecal samples from dogs living in households in which the dog or human family members had recently experienced vomiting or diarrhea, the most common norovirus infection symptoms. In these 92 fecal samples, researches found four of the samples to contain the human strain of norovirus, HuNov.

Because "generally species barriers seem to be rather strong for viruses," it was previously thought that animals did not carry human noroviruses, according to Carl-Henrick von Bonsdorff, co-author of the study and member of the faculty of veterinary medicine.

Von Bonsdorff says the most likely source of the disease is family members who have the disease, specifically small children, as norovirus is most commonly transmitted in feces, though can also be spread through saliva and vomit.

"Viruses are in general rather species specific. It seems very unlikely that the transmission would be as easy between man and dog," von Bonsdorff said.

He says the next step in studying human norovirus in animals is to look at whether the virus can multiply within a dog's intestines, or whether it only passes through the animal.