UN agencies are advising that cats be kept indoors in areas with outbreaks of the H5N1 bird flu virus, but stress that there is no evidence that infected cats have spread the virus to people.
Yesterday's announcement by the World Health Organization (WHO) and UN Food and Agriculture Organization follows the detection of H5N1 in cats in Austria and Germany in the past two weeks.
Researchers already know that H5N1 can infect cats, from pets to tigers.
But the recent deaths of H5N1-infected cats in Germany, Indonesia and Thailand have refocused researchers' attention on the mammals, raising questions about whether they can transmit the virus.
According to an article in Nature today (9 March), a cat found near a bird flu outbreak in poultry in Cipedang, Indonesia, was infected with a form of H5N1 that had genetic changes similar to those seen in samples from infected people, but not in samples from birds.
The article adds that research published in January found the H5N1 virus in the faeces and sputum of experimentally infected cats, suggesting that they might spread the virus more than previously thought.
Despite its calls for cats to be kept indoors, the WHO is maintaining a reassuring tone, pointing out that there is currently no evidence that domestic cats play a role in the transmission cycle of H5N1 viruses.
The WHO added that no human cases of bird flu could be linked with exposure to a diseased cat.
Nature also reports that Thai scientists will publish research next month describing how a cat died of H5N1 after eating an infected pigeon.
The cats that tested positive for the virus in Austria have since tested negative.