Mystery Virus Killing Dogs in Michigan Novel to U.S. But Familiar to Mexico City

Officials have been unable to identify the cause of a canine parvovirus-like outbreak killing Michigan dogs within days — but it bears resemblance to cases seen in Mexico. 

Cornell University College of Veterinary Medicine associate professor Elisa Mazzaferro told The Detroit News on Monday that the virus reminded her of cases treated by a Mexico City emergency clinician. Otsego County animal shelter director Melissa FitzGerald advised pet owners to head to a veterinarian immediately if their dog experiences parvovirus-like symptoms: loss of appetite, lethargy, bloody stool, vomiting, and diarrhea. 

“Canine parvovirus attacks rapidly, dividing cells, including those of the gastrointestinal tract, and leads to vomiting and diarrhea,” said FitzGerald.

Most of the dogs infected with the mystery virus test negative for canine parvovirus, and even dogs vaccinated for canine parvovirus have fallen ill. The virus usually kills dogs within three days. Over 50 dogs have died from the mystery illness so far. 

Canine parvovirus isn’t contagious to other animals or humans. 

On Monday, the Michigan Department of Agriculture and Rural Development (MDARD) reported that several preliminary samples of infected dogs tested positive for canine parvovirus during necropsies. However, MDARD didn’t attribute the outbreak to canine parvovirus definitively. State Veterinarian Nora Wineland clarified that they’d just launched their investigation and were awaiting further results. 

“We are still in the early stages of this investigation, but some of the first samples submitted to the Michigan State University Veterinary Diagnostic Laboratory were positive for canine parvovirus. However, there are more results pending and more to be learned,” said Wineland.

Michigan State University (MSU) Veterinary Diagnostic Laboratory (VDL) director Kim Dodd clarified to MLive that the state and university together would “explore novel explanations” like new virus variants if unable to find the cause of the outbreak.

MDARD announced its intervention in the outbreak last Friday.

The first cases appeared across Otsego County, before spreading to Clare County.

Otsego County Animal Shelter explained in a Facebook post earlier this month that most of the dogs who contracted the mystery illness in their area were under two years old and died within three days. On Monday, their director, Melissa Fitzgerald, clarified that they haven’t heard of any survivors. 

The shelter reported that they spoke with veterinarians throughout their county and MDARD — however, nobody has an explanation for the outbreak.

“No one has an answer. The best ‘guess’ is that this is a strain of parvo,” stated the shelter.

In an update, the shelter clarified that they’d received more reports beyond northern Michigan to include central Michigan. The shelter reported that properly vaccinated dogs hadn’t died from the virus in their area, in an apparent contradiction to their director’s remarks earlier this week.

However, Clare County Animal Control Director Rudi Hicks reported to the Clare County Board of Commissioners last Wednesday that both vaccinated and unvaccinated dogs infected with the mystery virus all died. Hicks said that the state was “in a panic” over the mystery virus. 

Until further notice, officials are advising Michigan dog owners to refrain from taking their dogs to dog parks and on walks.

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