The BC SPCA is urging dog owners in the Vancouver area to make sure their pets are vaccinated against parvovirus after six puppies were diagnosed with the deadly disease in the city's downtown core.

According to the organization, parvovirus—which is commonly referred to as just parvo—is "a highly contagious and often fatal viral disease that attacks the gastrointestinal system of dogs and can also damage the heart muscle."

“We are concerned that the six dogs…may have exposed other dogs in the community,” Dr. Emilia Gordon, senior manager of animal health for the SPCA, said in a statement.

“We urge any guardians of unvaccinated puppies or dogs to see their veterinarian and to seek immediate help if their pets show symptoms of the disease.”

Gordon said the disease is present at low levels in the community on a continuous basis, but the latest outbreak was first reported about six weeks ago.

Only two of the six infected puppies survived.

Puppies and unvaccinated dogs are most susceptible. Dogs can get it by coming in contact with feces from an infected dog, and the virus can live for several months.

“Parvovirus causes vomiting, loss of appetite, bloody diarrhea and lethargy,” Gordon said. “A dog with parvovirus may also have difficulty absorbing nutrients, increasing the risk for dehydration and malnutrition. Even with treatment, dogs can develop sepsis and die.”

According to Gordon, puppies should be vaccinated on a schedule determined by the dog's vet. She added that immunizations typically start at six to eight weeks of age, with follow-up boosters at four-week intervals until the animal is 20 weeks old.

Adult dogs that aren't vaccinated should receive at least one shot, she said.

There is a type of parvovirus that can affect humans, but canine parvo is a separate strain and cannot be spread to people.

The SPCA offers free vaccines on the last Thursday of every month to pets with homeless guardians and those living in SROs on Vancouver's Downtown Eastside.

The next clinic will be held on June 27 starting at 10 a.m. at Oppenheimer Park.

Pet owners can sign up by emailing charliesfoodbank@spca.bc.ca.