Questions Remain About H7N9 Avian Flu in China

There are now 126 confirmed cases of the new H7N9 bird flu, including 24 deaths. The cases have been reported from Beijing, Shanghai, and the following provinces: Jiangsu, Zhejiang, Anhui, Shandong, Henan, Jiangxi, Hunan, and Fujian. The majority of cases have been reported from Shanghai and the provinces of Zhejiang and Jiangsu. The virus spread to four other provinces in the last week or so (Fujian, Jiangxi, Hunan, Henan).

The big questions continue to be: are there many infections that are not causing illness and have not yet been detected? And how did people who had no contact with poultry become infected?

After closing live poultry markets, the number of new cases in Shanghai seems to have decreased. So far, there has been no verification of human-to-human transmissions. It is difficult to tell where the virus is hiding since infected poultry show no symptoms of illness. Experts from the World Health Organization have noted that this is an “unusually dangerous virus for humans.”

Interestingly, extensive testing of poultry farms has not turned up a single positive bird, and only a few positive results have been obtained from live poultry markets. It remains unclear how poultry became infected with the virus. Investigations are ongoing, however, the WHO expects that there will be more cases of human infection until the source has been identified and controlled.