Two dead crows have tested positive for bird flu (avian flu) in Japan. The crows were found near a chicken farm.

The worry among officials is that this disease may be more difficult to control than previously thought.

One crow was right next to a chicken farm that had had bird flu among its chickens. The other crow was about five miles away.

According to the authorities, these crows most likely caught the avian flu from the chickens in at the infected farm.

One official said 'We cannot completely rule out the possibility that the crows may have spread the disease but if that was the case then we would have seen more visible cases of dead crows much earlier.'

An executive who worked for the company that owned the infected chicken farm has committed suicide with his wife, said the police. People had complained that he had not reported the chicken deaths immediately. His name was Asada Nosan.

A nearby farm last Thursday became the fourth farm in Japan to be affected by bird flu.

All cases in Japan have had the H5N1 strain.