Mysterious parvovirus-like illness infecting dogs in Michigan, killing as many as 60 dogs

A mysterious illness is infecting dogs in Michigan and some cases appear to be deadly. It is a parvovirus-like illness, causing vomiting and bloody stools.

Parvovirus is highly contagious for dogs and is common in Michigan. A vaccine is available, and the virus is not contagious to other animals or people.

Otsego County has seen more than 30 deaths from the illness, Melissa FitzGerald, director of Otsego County Animal Control and shelter told CBS News. Clare County has had at least 10 deaths, and Ostego County has had about 10, but Fitzgerald said there could be more.

The Michigan Department of Agriculture and Rural Development said it received a report that a dog in northern Michigan was vomiting and had diarrhea. These are common symptoms of canine parvovirus, but the animal tested negative for the parvovirus at the veterinary clinic. 

Other animal control agencies in northern Michigan reported seeing dogs with the same symptoms, as well as others typically associated with parvovirus, like lethargy and loss of appetite. The causes of the symptoms had not been determined.

The state department is working with partners like the Michigan Association of Animal Control Officers, Michigan State University Veterinary Diagnostic Laboratory and the U.S. Department of Agriculture to learn more about the illness, but they are still in the early stage of the investigation. 

Samples were submitted to the state university lab and those tested positive for canine parvovirus – but there are more results pending, State Veterinarian Nora Wineland said in a statement. 

"When MDARD first learned of these cases in northern Michigan, we immediately reached out to the veterinarians and animal shelters involved and began our response efforts. Protecting animal and public health is one of the department's key pillars, but it is a team effort. Dog owners need to ensure their pet is up to date on routine vaccinations as it's the first step in keeping your pet healthy."

The department is urging pet owners to keep up with routine vaccinations for their dogs, clean up after their pets, keep unvaccinated puppies away from other dogs and keep any dogs exhibiting any signs of illness away from others.

Earlier this month, Ostego County Animal Shelter posted about the mysterious illness infecting dogs in the area, saying several dogs developed parvo-like symptoms, but tested negative. "Most of these dogs have passed within 3 days," the animal shelter wrote in its Facebook post. "These dogs are mostly under the age of 2. Some of the dogs were vaccinated."

"No one has an answer. The best 'guess' is that this is a strain of parvo," the shelter said at the time, adding that they had not spoken about the illness until then "because we really don't know anything."

The animal shelter had been in close contact with veterinarians in surrounding towns to try and figure it out Gaylord, Traverse City, Grayling, Mancelona and Indian River trying to figure this out, and said the infected dogs were not in any one area. 

Last Friday, the animal shelter posted an update, saying the illness does not affect certain breeds more than others, and the illness was detected in dogs from many counties around northern and central Michigan. The shelter said at the time that, while the perplexing disease has killed a number of dogs in the area, it had not seen any dogs die "that are properly vaccinated." In Clare County, Animal Control Director Rudi Hicks said last week that all dogs with symptoms of the illness had died regardless of their vaccine status, according to the Clare County Cleaver. 

The shelter said the illness could be a strain of parvovirus, although the cause is not yet known. It also also mentioned that there are "numerous" canine diseases that present symptoms similar to parvovirus, and veterinarians may therefore treat individual cases differently. Nonetheless, the shelter urged people to get their dogs properly vaccinated against the parvovirus. Otsego County Animal Control and the shelter will host a vaccine clinic for parvovirus this week on Wednesday, August 24 at the Otsego County Fire Department.

CBS News has reached out to the Michigan Department of Agriculture and Rural Development and Michigan State University Veterinary Diagnostic Laboratory and is awaiting response.