A dog in New York has been confirmed to have the pandemic strain of H1N1.
The pet, a 13-year-old mixed breed, seemed to have caught the virus from his owner, Michael San Filippo, a spokesman for the American Veterinary Medical Association, said Tuesday.
It is the first reported case of H1N1 in a dog, but other pets, including cats and ferrets, have caught the strain from humans, veterinarians say.
In theory, the strain could be transmitted from a pet to a human, "but so far it's really looking like a dead end in pets," San Filippo said.
The dog came in for a checkup Tuesday and is "getting back to his old self" but has not fully recovered, said veterinarian Julie Steffens.
It is rare for pets to spread flu viruses, and people should not be afraid to enjoy the animals, said Dr. Anne Schuchat of the U.S. Centers for Disease Control and Prevention.
So far, 111 million doses of H1N1 vaccine have been made available in the U.S., she noted.
"Surveys are showing that initial doses of vaccine were relatively quickly taken up and they were going to the people they were targeted for," Schuchat told reporters in a telephone briefing.
The agency estimates that nearly 50 million Americans have been infected with swine flu and 10,000 have been killed by it. Seasonal flu results in about 36,000 deaths a year in the U.S. and 4,000 to 8,000 a year in Canada. The death toll from swine flu in Canada as of Dec. 12 was 367.
The World Health Organization cautioned Tuesday against making comparisons between confirmed H1N1 deaths and seasonal flu deaths. The comparisons can be misleading and don't accurately measure the impact of the pandemic, given that H1N1 affects a much younger age group, WHO said in a briefing note.
It likely won't be possible to accurately assess the disease and death rates until a year or two after the H1N1 pandemic has peaked, using methods such as those used to estimate deaths during seasonal flu epidemics, the agency said.