Some Calgary veterinarians say they're treating more cases of canine parvovirus - a life threatening illness among dogs - that can be prevented by regular vaccinations.

The isolation room at the Fish Creek Pet Hospital has been full of dogs battling parvovirus, a highly contagious infection, Dr. Katie Van Sluys says. 

"Really, because this disease is so preventable from vaccines, we shouldn't have to worry about it," said Van Sluys. "It's sad."

Parvovirus, or Parvo for short, is either spread by direct contact with an infected dog, or indirectly, by the fecal-oral route.

Its symptoms include vomiting, diarrhea, fever and general weakness. It can also lead to dehydration, which if severe enough, can cause death. 

There is a vaccine that is highly effective and is usually included as part of a dog's regular shots.

Anti-vaxxer movement

But Dr. Van Sluys says a trend is emerging among pet owners who are choosing not to vaccinate their dogs, similar to the anti-vaccine movement with respect to human vaccines.

Dr Danny Joffe

Dr. Danny Joffe says anti-vaccine movement among pet owners is putting all dogs at risk of disease. (Colleen Underwood/CBC News)

"We do see more people thinking that vaccinations are not important or that they come with risks and I am not doing that to my dog. But unfortunately the risk of this disease is out there and threatening the adult population, if you are not vaccinated."

Van Sluys says anti-vaxxers are relying on what's called, herd immunity, that is, as long as a certain percentage of the dog population is vaccinated, the disease has a harder time spreading.

Dr.Danny Joffe, the medical director at the Care Centre Animal Hospital,  says these decisions are being driven a lot by unresearched opinions on the internet.

"Are vaccines innocuous? No. They are biological and they can cause side effects just like they can in people. But for most patients, and again this should be assessed by your veterinarian, but in most cases, the benefits of vaccinating far, far, far outweigh any risks of giving the vaccine."

Even coyotes at risk

As the population of unvaccinated dogs grows in Calgary, Dr. Joffe says the disease will become more prevalent, even affecting vaccinated dogs — especially those with weaker immune systems which didn't respond well to the vaccine.

"It puts the entire canine population at risk. And in a city like Calgary where we have a large urban coyote population as well, which also pick up these same diseases, it just ends up causing a snowball effect," said Joffe.

Until now, the disease was usually found in puppies, who were not fully protected against the disease. But Dr. Van Sluys says its becoming more common to see it in adult dogs, which can catch staff off guard.

"It's really unfortunate when you have a vomiting three-year-old Labrador. In most people's minds, that's a foreign body, [they've] eaten a rock or a sock," said Sluys.

"It's really unfortunate situation when you make a diagnosis of parvo in surgery."

Cost of vaccine vs. treatment

Pet owners should also consider the cost involved of treating this particular disease, says Dr. Van Sluys. 

She says parvo-dogs can be in the hospital anywhere from a couple of days to a couple of weeks.

"A very intense therapy, which can be challenging for some owners to face... a vaccine versus a $2,000 vet stay."

The parvo-vaccine is usually given in combination with one for distemper, and it is recommended for puppies at 8, 12, 16 weeks, again at 18 months, and then every three years afterwards.