Human infection with avian influenza A(H7N9) virus in China

 Photo Courtesy of WHO Collaborating Centre for Reference and Research on Influenza, National Institute of Infectious Diseases, Japan

17th April 2013,Hyderabad, India – The National Health and Family Planning Commission notified WHO of an additional 19 laboratory-confirmed cases of human infection with avian influenza A(H7N9) virus. The latest laboratory confirmed cases, there are nine from Zhejiang Province, seven from Shanghai Municipality and three from Jiangsu Province.

Additionally, 3 patients earlier reported have died. To date, a total of 82 patients have been laboratory-confirmed with human infection with avian influenza A(H7N9) virus in China, including 17 deaths. More than a thousand close contacts of the confirmed cases are being closely monitored.

Investigations into the possible sources of infection and reservoirs of the virus are ongoing. Until the source of infection has been identified, it is expected that there will be further cases of human infection with the virus in China. So far, there is no evidence of ongoing human-to-human transmission.

WHO does not advise special screening at points of entry with regard to this event, nor does it recommend that any travel or trade restrictions be applied.

Influenza A(H7N9) is one of a subgroup of influenza viruses that normally circulate among birds. Until recently, this virus had not been seen in people. However, human infections have now been detected. 

As yet, there is limited information about the scope of the disease the virus causes and about the source of exposure. The disease is of concern because most patients have been severely ill. There is no indication thus far that it can be transmitted between people, but both animal-to-human and human-to-human routes of transmission are being actively investigated.