Two cases of bird flu in humans involving family members in Nanjing, capital city of Jiangsu Province, have been effectively contained, Ministry of Health said, adding all close contacts involved have been released from medical observation.

"None of those in close contact showed unusual symptoms and they were all released from medical observation on Dec. 12," the ministry said in a statement posted at its website (www.moh.gov.cn) on Thursday.

China announced on Dec. 2 that a 24-year-old man surnamed Lu in the provincial capital Nanjing died of H5N1 infection. On Dec. 7, the man's father was also confirmed to be infected with the virus.

About 80 people who had contact with either man were put under close medical observation.

"The father, who has been under intensive medical treatment, is in stable condition and showing signs of improvement," the ministry said in the statement.

So far, the means of transmission remained unknown and experts were still conducting an investigation.

The son was said to have no known contact with dead poultry. In addition, the Jiangsu Animal Husbandry and Veterinary Bureau said last week that no bird flu epidemic had been discovered in the province.

The ministry said that local health authorities had tightened monitoring on pneumonia cases and collected a large number of samples. "All samples tested (H5N1) negative and no suspicious or unusual cases were discovered," it said.

The latest cases bring the number of confirmed bird flu cases in humans in China to 27 since 2003. During that period, there have been 17 deaths.

(Xinhua News Agency December 14, 2007)