WASHINGTON – Cats not only can catch the deadly bird flu but can spread it to other felines, Dutch researchers said in a report Thursday that raises important questions about the pets’ role in outbreaks.
So far, cats have not been implicated in the spread of avian flu to people, said Dr. Klaus Stohr, the World Health Organization’s influenza chief.
There are two potential reasons, he said. “One is nobody looked. The other is they don’t play a role” because infected cats do not shed nearly as much virus as infected poultry, Stohr said.
There have been recurring outbreaks of bird flu in recent years, and it has killed 27 people in Asia so far this year. Until now, human infections have been traced to direct contact with infected poultry or poultry waste, and millions of chickens and other fowl have been slaughtered in attempts to stem the disease.
Hearing of the Dutch discovery, the WHO urged scientists to examine household cats and other mammals whenever researchers investigate human bird flu infections. The first such check, in Vietnam last week, found cats in patients’ households were healthy, Stohr said.
The cat research “is of considerable concern” because it illustrates the virus’ continuing adaptation in mammals, said Dr. Nancy Cox of the federal Centers for Disease Control and Prevention.
“It increases opportunities for human infection, this time from a mammalian species,” said Cox, who wonders if dogs, too, are infected. “We need to do a lot more in the veterinary arena in order to understand what other animals can be infected and can transmit the virus.”
Because bird flu is quite different from the flu strains that normally infect people, scientists fear it eventually could lead to a human flu pandemic. So they are closely watching for the virus among other mammals.
Last winter, Thai veterinarians reported that bird flu had killed three house cats. That was a surprise, because domesticated cats have long been thought to be resistant to infection from influenza A viruses. The new research, reported in the journal Science, shows that cats fairly easily spread the disease to one other.
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