While most viruses aren’t transferrable from humans to pets, and vice versa, one Michigan veterinarian is saying that a mysterious dog virus, which has already killed six dogs, could be one of those rare instances.

Dr. Lindsay Ruland, of the Emergency Veterinary Hospital in Ann Arbor, has seen several dogs with symptoms similar to those caused by canine circovirus, including vomiting, bloody diarrhea, lethargy, and inflammation of the intestinal tract. The virus causes blood vessels to leak and blood to thicken, making it difficult for nutrients and oxygen to get to vital organs. So far six deaths and 36 veterinary visits have been attributed to the virus. In Ohio, the virus has also been linked to an additional four dog deaths.

“This is like nothing we’ve ever seen before, and I don't know if it’s multiple viruses in combination or just the circovirus,” Ruland told the Columbus Dispatch. Infected dogs are usually killed within 12 to 24 hours of the onset of symptoms, she told ABC5.

The virus is under investigation because the affected dogs’ owners also showed signs of flu-like symptoms, Ruland said. Furthermore, the veterinary staff developed flu-like symptoms after treating the dogs, including abdominal and respiratory issues.

“Traditionally, we don’t pass viruses to our pets. This year, I think that there is potential that we are passing it to our pets,” Ruland told ABC5. She also reported her own pain coming from “right beneath my ribs.”

According to the American Veterinary Medical Association (AVMA), the viruses were not identified in the sick dogs’ stool, but it's unknown whether such testing is valid. An autopsy performed at Ohio State University Veterinary Medical Center on one dog who died while infected by the virus couldn’t establish the cause of death.

Canine circovirus was originally discovered in a one-year-old dog in California last year. However, the dog was euthanized before the virus could be properly studied, leaving it unclear whether this new slate of illnesses is related. “The relationship to the canine circovirus is unknown,” Dr. Mike Oglesbee, chairman of the OSU Veterinary Biosciences Department, told the Dispatch. “It’s a priority to dig down into this, but were at step zero.”

Meanwhile, the AVMA urges pet owners to contact their veterinarian if their animal is vomiting or has diarrhea. These symptoms aren’t exclusive to a circovirus-like illness, and could be an indication of something else. Although the mode of transmission of the virus is still unclear, the AVMA says that there’s no cause for panic. Avoiding other dogs’ stool is one way to try to prevent infection.