An outbreak of canine virus in the Puget Sound region has dog owners nervous.

The Everett Herald reports that parvovirus is highly contagious, can be deadly for young dogs and can live in dirty areas for a long time.

The discovery of the virus in the area prompted the cities of Everett and Mukilteo to close municipal off-leash dog parks this week. In Seattle, there has been a spike in the number of reported cases.

Washington State Veterinary Medicine Association spokesman Charlie Powell says parvovirus is always in the environment and outbreaks occur periodically.

“It’s important to note that parvovirus is in the environment all the time and that outbreaks occur sporadically,” he said. “Unvaccinated dogs are at risk, but some dogs who have the vaccine may not even be able to fight it. There is no way to avoid the risk of catching parvo, but you can keep your dog out of kennels and boarding facilities where parvovirus has been present.”

Symptoms include vomiting, diarrhea, dehydration and lethargy.

Powell said there isn’t a way to tell if the virus is present at a park.

“However, there is no way to tell whether the virus is at the park two weeks from now. It’s like saying we can control the common cold,” Powell said. “You can vaccinate, sanitize water dishes and living areas and quarantine sick animals, but that’s about it.”

He added that dogs can survive parvovirus, “but it’s really hard on them.”

Everett officials are keeping dog parks closed until further notice, but parks in King County, including the one at Luther Burbank, remain open.