A cat walks through bushes in the small town of Schaprode on the northern German island of Ruegen

German officials have ordered cats to be kept indoors and dogs to be kept on leashes in areas hit by the deadly strain of the bird flu virus.

The action comes after tests showed that a cat found dead in the northern island of Ruegen was infected with the H5N1 virus.

Experts say the cat probably ate an infected bird, the same way big cats in Asia have contracted the disease.

It was the first mammal in the European Union to be infected with H5N1.

The German government has imposed the restriction on cats and dogs within a three-kilometer radius of where infected birds were found.

The World Health Organization says it is not known if cats can infect humans. An organization statement says there has been no documented case of such a transmission.

Some information for this report was provided by AFP, AP and Reuters.