The Saskatoon SPCA is warning people to vaccinate their animals after several dogs were found with parvovirus over the past several weeks.

The organizations says the virus, which attacks dogs' gastrointestinal tract, is very contagious and potentially deadly.

"It causes vomiting and severe, bloody diarrhea and dehydrates the animal," said executive director Patricia Cameron. "It can cause neurological damage as well."

Parvovirus is spread through animal feces and is very resilient.

"It's a very hearty virus," said Cameron. "If, say, you're walking down your street, and a parvovirus animal has shed on the sidewalk, even when it's not visible, you can take it into your home, or wherever you're going in the neighbourhood."

The SPCA is asking all dog owners to vaccinate their animals, especially puppies, who are especially susceptible to the disease.

"It's especially important to ensure if you have a puppy, that the puppy has the total three-round vaccination before ever being taken out to, for example, a dog park," she said.

The SPCA said about 70 per cent of dogs infected with parvovirus survive, but infected animals often need long-term veterinary care afterward.