Schrödinger's cat, dead or alive

Like Schrödinger's cat, the vital status of a case of feline H5N1 infection seems to be a matter of probability. If you are a German-speaking cat in Rügen you are dead. If you are a German-speaking cat in Graz, Austria, you are alive. Yesterday two more cats dead from H5N1 infection have been discovered in Rügen, bringing the total to three. But three cats near infected birds in a wild animal park in Graz showed signs of having been infected but didn't get sick.

Good news? Not necessarily:

Reports that a cat contracted bird flu and has not fallen ill could mean the virus is adapting to mammals and poses a potentially higher risk to humans, a World Health Organisation (WHO) official said on Tuesday.

Michael Perdue, a scientist with the WHO's global influenza programme, said more studies were needed on infections in cats, including how they shed the virus. (Reuters)

Don't despair. The cat could still die.

However, the virus can take up to a week to strike and perhaps the cat in Austria could still develop clinical signs, according to Perdue.

"We have to follow-up with laboratory studies to see if it (the virus) changed genetically and is not causing clinical signs," Perdue told Reuters.

"If it is true, it would imply the virus has changed significantly," he said.

The virus freely circulating in cats is another nightmare scenario. Something else to worry about.