Dogs dominated the local and state news cycle this week as word spread about an outbreak of a mysterious canine affliction in Otsego County. “At least 30 dogs dead of mysterious parvo-like illness in one Northern Michigan county” noted an MLive headline from Monday, which quickly caught the attention of local residents. What is this mystery illness, what does it mean for local dog owners, and how can you keep your pets safe? The Ticker investigates.

Media coverage and social media chatter about the outbreak grew over the past few days, but the problem itself has actually been brewing for much of the summer. On August 9, Otsego County Animal Shelter shared a post on Facebook acknowledging that numerous dogs in the county had exhibited a similar pattern of illness “over the last month.” Those dogs, the post said, had “gotten sick with what appears to be parvo,” short for canine parvovirus. Parvo is a common and highly contagious virus that spreads through direct dog-to-dog contact, as well as through canine feces. Symptoms typically include lethargy, vomiting, diarrhea, and bloody stool.

Per the Otsego County Animal Shelter post, the sick dogs were presenting with typical parvo symptoms. The twist is that, when local veterinarians tested the dogs for parvo, most of those tests came back negative. The majority of the infected dogs died “within three days,” and some of them, Otsego County Animal Shelter said, had even been vaccinated against parvo.

According to Jaime Bemiss, who serves as animal control supervisor for the Grand Traverse County Health Department, much remains unknown about this curious canine health scare. In particular, there are still question marks about what is causing the illness, where it originated, and why it’s evading tests that would normally detect parvo. The first of those questions, it seems, is closest to getting a concrete answer.

“What the Michigan Department of Agriculture & Rural Development (MDARD) is seeing [is positive parvo test results],” Bemiss tells The Ticker. “Once the samples are getting sent to MDARD, their lab is testing them, and those samples are testing positive. But the same samples are testing negative at local vets.”

Why the disparity? Potentially, it just means that local tests aren’t sensitive enough to flag this illness as parvo. Bemiss says that a parvo test from a local vet is “usually a snap test,” designed to deliver faster – but sometimes less accurate – results. “The lab tests down in Lansing are going to be stronger and more in depth,” she adds. “So, that might be part of the issue. There might need to be a change in how we’re testing dogs for parvo.”

Bemiss says it’s “very possible” that this perplexing dog illness is ultimately just a new strain of parvo. In that situation, she says there is some good news – namely, that there has been a highly effective parvo vaccination available “for a long time” and that vets are well-versed in providing care for dogs diagnosed with the illness. The bad news is that the symptoms of parvo can be indicative of numerous other illnesses, which means vets normally rely on accurate tests in order to plan treatment.

“The symptoms of parvo do overlap with the symptoms of a lot of other diseases,” Bemiss explains. “The loose stools, the vomiting, the lethargy – those three symptoms overlap with a lot of other things. With parvo, the main problem is actually dehydration. Generally, when dogs succumb to parvo, it’s because they became dehydrated. So, the veterinarian has to treat that with fluids and medication, but each individual vet might treat it a little differently, depending on what stage they think the disease is in in. And they're relying on those tests [to know how to treat the illness], so the fact that these tests are coming back negative is definitely a concern.”

The best protection against any version of parvo, Bemiss says, is still complete and up-to-date vaccination in all dogs. She notes that, from her understanding, “the vast majority of these parvo cases are in young, unvaccinated or incompletely vaccinated dogs.” When asked about the Otsego County Animal Shelter’s statement that some of the affected dogs had in fact been vaccinated, Bemiss suggested that those vaccinations may have been incomplete or out-of-date.

On Wednesday, MDARD issued an update that confirmed Bemiss’s suspicions: The outbreak, MDARD says, is indeed parvo, and the affected dogs “did not have a history of complete vaccination.” The press release urged vigilance in the vaccination of dogs to prevent further exacerbation of the outbreak, including “timely boosters” for dogs that have already been vaccinated. MDARD also urged dog owners to clean up after their pets in order to avoid spread of the virus through fecal matter.

The MDARD release included comments from Kim Dodd, a veterinarian at the Michigan State University Veterinary Diagnostic Laboratory (MSU VDL), who explained why dogs might have been testing negative for parvo at local veterinary offices. The MSU VDL is the lab that re-tested the northern Michigan samples and confirmed them as parvo.

“This situation is complex because although the dogs displayed clinical signs suggestive of parvovirus, they consistently test negative by point-of-care tests performed in clinics and shelters,” Dodd said. “Screening tests for parvo are done to help guide immediate isolation, disinfection, and treatment protocols. While those tests are valuable in the clinical setting, they are not as sensitive as the diagnostic tests we can perform here in the laboratory. We continue to further characterize the virus in hopes of better understanding why those animals were testing negative on screening tests.”

Bemiss recommends that dog owners check with their vets to make sure their four-legged friends are up-to-date on all vaccinations, including parvo. Beyond that, she advises that people “be careful where you take your dog, if it’s immune-compromised in some way or not vaccinated completely.” Puppies and young dogs, she notes, are particularly at risk for the disease. A full parvo vaccination series requires three shots, which means most dogs won’t be fully protected against the disease until 16 - 24 weeks.

“Obviously, the doggy daycares and boarding facilities, they all have vaccine requirements,” Bemiss says. “But just be vigilant with your particular dog. If you know your dog gets sick a little easier, or has some sort of immune-compromised situation, then maybe that’s a dog you should be keeping away from other dogs right now until there’s some more information about this situation.”