DETROIT (WWJ) – Reports from across the U.S. say the highly contagious dog influenza virus is spreading nationwide for the first time in years.

This season, dog flu has turned up everywhere from California to Washington to Pennsylvania and recently into Canada, according to Newsweek. One San Francisco clinic saw 50 cases in just two weeks, reports say, and the virus is spreading to areas that haven’t seen an outbreak in several years, if ever.

Earlier this month, Fox News reported that two different strains of dog flu had been confirmed in at least 46 states; but thus far this year, officials have not confirmed an outbreak of cases of dog flu in Michigan. (Amid a Midwest outbreak in 2015, three cases of canine flu were confirmed in Michigan, including one in Macomb County and two in Kent County).

According to Michigan State University Veterinarian Thomas Mullaney, symptoms of dog flu include lack of appetite, lethargy, cough and fever. The viral infection is spread through barking, coughing, and sneezing when pets are in close contact with infected animals. It often spreads through kennels, dog shelters, groomers, and doggy day care centers.

Most dogs recover within two to three weeks. However, if it’s not treated properly, the dog flu comes with a 10 percent mortality rate, according to the American Veterinary Medical Association, and dogs of any breed, age, sex or health status are at risk.

Some infected dogs may not show any signs of illness, but can still be contagious and able to infect other dogs. The virus can be fatal for cats, too — but it should be noted that canine flu does not sicken people.

[Learn more: Canine Influenza: Pet Owners’ Guide].

A dog flu vaccine is available; but not all dogs need it, so ask your vet. Mullaney said it’s often recommended that people who travel with their dogs get those pets vaccinated.