Nov. 18 (UPI) -- Dog owners and veterinarians are growing increasingly concerned over a highly contagious, possibly fatal respiratory illness spreading in several states.
The mystery illness starts as a cough that can last weeks and doesn't respond to normal treatments, like antibiotics. It can then morph into severe pneumonia that can leave a dog struggling to breathe. The American Veterinary Medical Association said the pneumonia can get worse in as little as 24 to 36 hours.