ACCES, or Animal Critical Care and Emergency Services, in Seattle and Renton issued an alert to vet offices over the weekend after identifying seven cases in two weeks -- a spike in a year with an already-alarming tally.
"We treat about 16 cases a year. We've seen 27 so far this year," said Dr. Beth Davidow, medical director of ACCES.
Vets say the potentially-deadly virus spreads easily and can live for a long time in contaminated soil or on dog fur. Pet owners are strongly urged to vaccinate their dogs.
Davidow describes canine parvo as a highly contagious virus, especially dangerous to young dogs.
"Puppies die if they're not treated," she said. "You're making a mistake if you're taking your week-old puppy to the dog park. It's like taking your newborn to a daycare center."
The virus spreads most commonly when dogs are exposed to contaminated feces. But animals can get infected from water dishes, toys and even an owner's hands and clothing.
Major symptoms to watch for include vomiting, diarrhea and lethargy.