Chinese health officials say a man in southwestern China has died of bird flu, the second fatality from the H5N1 virus this year.

The Guizhou provincial health department said Saturday that the 31-year-old died of multiple organ failure Friday in a hospital in the city of Guiyang.

China's official Xinhua news agency said another patient, a 21-year-old woman, died of the avian flu last Sunday. Xinhua said both patients had close contact with birds.

The agency said 110 people who had contact with the patients have been released from quarantine.

Most bird flu cases in humans come from close contact with infected poultry. Researchers fear the virus might eventually mutate into a form that is highly contagious among humans.

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