Domestic cats in Germany and Austria have contracted the H5N1 avian influenza virus, causing concern among pet owners in Europe and the United States.
According to the World Health Organization, domestic cats on the German island of Ruegen died of the disease—presumably after feeding on infected birds. A marten, a mammal in the same subfamily as weasels, also contracted the virus on the island.
Cats at an Austrian shelter in Graz might have contracted the H5N1 avian influenza virus, too, according to the European Centre for Disease Control and Prevention. The shelter had previously detected the disease there in chickens.
Anecdotal evidence suggests that domestic cats in Asia have contracted the virus in the past. Large cats in captivity have become infected as well. In Thailand, tigers and leopards in zoos have died after consuming chicken carcasses. In Vietnam, captive civets died of the disease.
According to Dr. James Richards, director of the Cornell Feline Health Center, research has shown that domestic cats can become infected with the H5N1 avian influenza virus after eating raw meat from infected birds. Research has also revealed that domestic cats can spread the disease directly to other cats.
"There is no evidence that influenza-infected cats can in turn infect humans," according to Dr. Richards, who is also a past president of the American Association of Feline Practitioners.
Dr. Richards' summary of avian influenza in cats is available online through the feline health center at www.vet.cornell.edu/FHC/. He writes in "Bird Flu: A Danger to Felines?" that most, and maybe all, of the humans who have become infected with H5N1 avian influenza have had close contact with infected birds.
Dr. Daniel Aja, immediate past president of the American Animal Hospital Association, said he has heard about European pet owners abandoning cats for fear of the disease. He said veterinarians in the United States need to step forward to educate clients on the topic.
"We have to be proactive, but we can't panic," said Dr. Aja, who co-owns Cherry Bend Animal Hospital in Traverse City, Mich. "The last thing we want to see is people getting rid of their pets needlessly."
Dr. Aja said he's discussed H5N1 avian influenza with clients who have pet birds much more often than those who have pet cats. However, Drs. Aja and Richards offer some simple suggestions for reducing the already-low risk of feline infection.
"It's just another reason to make cats indoor cats," Dr. Aja said. "It's also a good reason for us to be cooking anything we're feeding to our pets."
Dr. Richards writes that feeding commercial cat food eliminates the risk of infection because temperatures during manufacturing exceed the 70 C necessary to destroy the H5N1 avian influenza virus. He adds that keeping cats indoors prevents exposure both to birds and outdoor cats that might be infected.
The AAHA summary of avian influenza in cats for pet owners, "Avian Influenza and Your Cat," is available at www.healthypet.com.
The ECDC is also advising European pet owners to keep cats indoors and to follow general rules of hygiene when handling food, cat litter, or dead animals.
As of March 24, the WHO had reported 186 human cases of infection with H5N1 avian influenza virus—leading to 105 deaths. Dozens of countries across Asia, Europe, and Africa had detected the disease in wild birds or domestic poultry.
In addition to cats and martens, pigs and ferrets are also susceptible to infection. Information about the H5N1 avian influenza virus in cats and other animals is also available on the AVMA site at www.avma.org.