Winter flu season just got a little scarier. Health officials report that a rare strain of avian flu, known as H7N2, that recently spread among more than 100 cats in New York City animal shelters appears to have infected a local veterinarian. If confirmed, this would be the first known transmission of this subtype of the bird flu from feline to human, CBS News reports

Although H7N2 is a strain of the influenza A virus that’s considered to be of low risk to human health, medical experts still urged New Yorkers to watch for flu symptoms in their pets. In addition, the city’s health department urged people not to nuzzle sick cats.

Doctors said the vet infected with the flu bug recovered from a “mild” illness and there was no sign that the virus spread to other shelter workers. So far, more than 160 employees and volunteers have been tested for the flu strain, but only the vet appears to have been infected. New York City health officials also contacted 80 percent of the people who adopted cats from the affected shelters, but no one else was infected. 

As for the felines, only one cat diagnosed with the avian flu has died; the others are expected to make a full recovery. Officials temporarily halted adoptions of the animals in New York City and quarantined all sick cats until the potential pets were judged not to be a risk to human health. In addition, public health representatives advised residents not to bring stray cats to any Animal Care Center at shelters in the city until the outbreak is over.

Previously, there have been only two other documented cases of the transmission of this avian flu subtype to humans in the United States: one in 2002 and the other in 2003. But a review of the 2003 case concluded that these infections could be a sign that the H7N2 virus might be slowly evolving into a humanized strain that could cause a pandemic.

To be prepared for this possibility, immunologists nationwide continue to keep a close watch on cases of this type. 

Click here to learn more about the flu virus and how health researchers are trying to prevent it.