A new virus is hitting dogs throughout the country, and if not treated, it can kill an infected animal in just days.

There's no vaccine, it's highly infectious, and scientists still can't say with certainty how it's transmitted. What is certain is this disease is deadly, especially in kennel settings. Even though cases have been limited to just three states so far - California, Michigan, and Ohio.

It's called circo-virus. Vets have been aware of it for years but mainly in pig populations.It can decimate an entire hog farm in just a week. Certain pet birds also seem susceptible, especially parrots, parakeets and cockatoos. What's new is the virus has never made the jump to dogs.

Doctors do know that dogs who are frequently boarded or spend time in "play situations" with large groups of other dogs are at greatest risk. The bad news is, there's no vaccine to prevent it - no known cure - and to make matters worse, it's still not clear how the virus is spread.

Here's what we know: all of the infected dogs had severe inflammation in their intestinal tract, and exhibited varying degrees of lethargy, vomiting, and diarrhea. If your dog exhibits those symptoms, visit the vet immediately.