Japanese authorities fear bird flu spread in wild birds

The discovery of another swan killed by bird flu in Japan has concerned health authorities.

The dead swan was found on the northern island of Hokkaido and authorities have confirmed that the wild bird was infected with the H5N1 strain of bird flu.

Another case, also in a dead swan, found five days ago near Lake Saroma in eastern Hokkaido, has also been confirmed as bird flu, this latest case apparently had the same strain found in another dead swan found on April 24th on another part of the island.

This latest case is Japan's third outbreak this year; several swans were found in April with the H5N1 strain on the shores of Lake Towada, close to the northern tip of the main island of Honshu.

Japanese authorities are concerned that the bird flu virus may be spreading among wild birds in the north but so far officials in Hokkaido say no poultry have been affected.

Health authorities will inspect three nearby poultry farms and disinfect 180,000 chickens as a precaution and scientists at Hokkaido University are conducting gene tests to find out more information about the cases.

Officials say the period when swans fly into Hokkaido has now peaked and only about 500 remain in a lake on the tip of the island.

Even though the virus remains a disease mainly of birds which is difficult for people to catch, scientists are concerned the virus will ultimately mutate into a form that spreads more easily between humans, with the potential to kill millions worldwide.

According to the World Health Organisation at least 240 people have died from bird flu since 2003, and most human cases have been las a result of close contact with infected poultry.

To date Japan has reported no human cases of the bird flu virus.