SAN FRANCISCO (CBS SF) — A dangerous and sometimes deadly virus that has affected thousands of dogs in the Midwest has shown up in California.

The canine influenza has hit 13 states, but so far has shown no signs of popping up in the San Francisco Bay Area.

READ MORE: Splash Brothers Curry, Thompson Lead Warriors Past Pistons, 102-86

The SPCA and Animal Care and Control Of San Francisco has not confirmed any cases, however vets on high alert for its spread.

KPIX Pet Expert Dr. Jill Chase said just like with the human flu, it can spread through the air. Dogs increase their chance of getting the flu if they come across an infected dog at a park, kennel or other enclosed space.

READ MORE: Friends, Loved Ones Remember Michelle Go, Killed In NY Subway Attack At San Francisco Chinatown Vigil

ALSO READ: South Bay Dog Owners Warned After White Powder Found On Popular Trail

Chase says pet owners should look out for:

  • coughing
  • sneezing
  • anorexia
  • fever
  • malaise
MORE NEWS: 2 Pedestrians Killed, 2 Hurt In Crash In San Jose

“Anytime there is a sign of illness, any change whatsoever, you should call the vet right away,” Chase said. “Don’t wait three or four days.”