On 18 March 2016, the National Health and Family Planning Commission (NHFPC) of China notified WHO of 29 additional laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus, including 11 deaths.

Onset dates range from 17 January to 19 February. Cases range in age from 21 to 78 years, with a median age of 57 years. Of these 29 cases, 22 (76%) are male. The majority (24 cases, 83%) reported exposure to live poultry, slaughtered poultry, or live poultry markets; the exposure history of 5 cases is unknown or with no clear exposure to poultry. Cases were reported from 6 provinces and municipalities: Zhejiang (7), Hunan (7), Jiangsu (6), Guangdong (4), Fujian (3) and Shanghai (2).

Three clusters were reported:

• The first cluster consists of two 35-year-old males (twin brothers) from Jiangsu Province, the onset dates are respectively 19 January and 1 February. Both have no clear known history of exposure to poultry.
• The second cluster consists of a 29-year-old male from Zhejiang Province and a 56-year-old female (son and mother) from Fujian Province. The onset dates are 4 February and 15 February, respectively. Both have history of exposure to live poultry market.
• The third cluster consists of a 21-year-old female and a 26-year-old male (sister and brother) both from Jiangsu Province, the onset dates are 14 February and 19 February, respectively. The brother reported exposure to live poultry. The sister took care of her brother and has no known history of exposure to poultry.

The investigation report of the Second cluster cases (published on June 2017) is available at: http://www.flu.org.cn/scn/article_detail.asp?articleId=11682