Fear of a deadly outbreak of a dog disease in King County has led to the closure of dog parks in a Snohomish County city.

The city of Everett said there are unconfirmed reports of dogs falling ill after visiting one of Everett's three dog parks.

As a result, Lowell Park, Howarth Park on Puget Sound, and Loganberry Lane Park near Paine Field have been temporarily closed. 

At Lowell Park, KIRO 7 Eyewitness News reporter Rick Price found new signs dated Wednesday warning dog owners of a parvovirus outbreak in King County, and announcing that the off-leash area there is closed until further notice.

A news release from Everett said parvovirus is potentially deadly, spreads easily and can live in untreated areas for long periods of time.   Get more information on canine parvovirus.

The Northwest has seen outbreaks of the disease before that attacks the digestive system of dogs, usually puppies.

Symptoms include loss of appetite, vomiting and lethargy, but an infected dog can shed the virus for weeks before showing any signs of illness.

There is a vaccine that can prevent parvo, and treatment for infected dogs, but the mortality rate for untreated infections is more than 90 percent.