Only eight dogs, all greyhounds. have been confirmed dead from the virus, says the chief of medicine at the Animal Medical Center in New York.

Early estimates are that it kills fewer than 5 percent of the dogs that catch it.

There are no known cases of its infecting humans.

Rumors, Hysteria

Nonetheless, with the approach of human flu season and fears about bird flu in Asia, there is much confusion and worry, especially among dog owners.

"The hysteria out there is unbelievable, and the misinformation is incredible," said Dr. Ann Hohenhaus, chief of medicine at the Animal Medical Center in New York. She said she had heard of an alert from a Virginia dog club reporting rumors that 10,000 show dogs had died.

"We don't believe that's true," she said, adding that she knew of only eight dogs confirmed dead from the virus, all greyhounds. No dogs in her Manhattan hospital even had the symptomatic cough, she said.

No Natural Immunity or Vaccine

Because there is no natural immunity or vaccine, virtually every dog exposed will catch the virus, according to researchers at the University of Florida and Cornell University who first isolated it.

About 80 percent will develop clinical signs: a cough that lasts as long as three weeks, runny nose and fever.