The Hong Kong Centre for Health Protection (CHP) of the Department of Health (DH) today (December 22) received notification of seven additional human cases of avian influenza A(H7N9) in Xinjiang Uyghur Autonomous Region (Xinjiang) (four cases), Zhejiang (two cases) and Jiangsu (one case) from the National Health and Family Planning Commission.

The patients comprise five men and two women aged from 36 to 81. Four of them (three from Xinjiang and one from Jiangsu) died while two of them (one from Xinjiang and one from Zhejiang) are currently in serious condition. The remaining case from Zhejiang is now in mild condition and did not require hospitalization.

To date, 454 human cases of avian influenza A(H7N9) have been confirmed in the Mainland in Zhejiang (141 cases), Guangdong (111 cases), Jiangsu (59 cases), Shanghai (42 cases), Hunan (24 cases), Fujian (23 cases), Anhui (17 cases), Jiangxi (eight cases), Xinjiang (eight cases), Beijing (five cases), Shandong (five cases), Henan (four cases), Guangxi (three cases), Jilin (two cases), Guizhou (one case) and Hebei (one case).

According to the World Health Organization, Avian influenza A(H7N9) is a subtype of influenza viruses that have been detected in birds in the past. This particular A(H7N9) virus had not previously been seen in either animals or people until it was found in March 2013 in China.

However, since then, infections in both humans and birds have been observed. The disease is of concern because most patients have become severely ill. Most of the cases of human infection with this avian H7N9 virus have reported recent exposure to live poultry or potentially contaminated environments, especially markets where live birds have been sold. This virus does not appear to transmit easily from person to person, and sustained human-to-human transmission has not been reported.