A Chinese bus driver named Chen died from the H5N1 bird flu virus on 31 December 2011 in the city of Shenzhen,a city bordering Hong Kong. Health officials said that this was the country's first reported case of the disease in humans in 18 months.

Chen developed a fever on 21 December and was hospitalized on 25 December. During the previous month Chen, aged 39, is not known to have had any direct contact with poultry. H5N1 rarely infects humans - usually only those who have close contact with diseased poultry - but among those infected, nearly 60 percent die. Scientists are watching closely watching for any signs that the virus is becoming more easily transmissible from human to human.

Chinese Health Authorities said that, amongst the 120 people who had close contact with Chen, none have, so far, developed any H5N1 symptoms.