LANSING, Mich. (AP) – State officials say an illness that’s sickened dogs in northern Michigan, killing some, was canine parvovirus.

It’s a common illness, but affected dogs were not fully vaccinated against it.

Kim Dodd, director of Michigan State University’s Veterinary Diagnostic Laboratory, said Wednesday the ailing dogs had “consistently” tested negative for that virus in testing at veterinary clinics and animal shelters.

She said testing confirming the canine parvovirus infections in affected dogs in Michigan’s northern Lower Peninsula was done at the university’s lab in Lansing and facilitated by the Michigan Department of Agriculture and Rural Development.