Influenza specialists from around the world are converging on China to help authorities identify how people are catching the new H7N9 bird flu strain after the number of reported cases there doubled in the past week.
China recorded its 88th H7N9 infection yesterday. Seventeen of the cases have been fatal and “several” patients are in critical condition, according to the World Health Organization.
“That’s a fairly high mortality rate,” Michael O’Leary, the WHO’s China representative, told reporters in Beijing today. Less severe cases may have escaped detection, he said. “What we don’t know is the size of the iceberg under this tip.”
China’s H7N9 bird flu outbreak has a puzzling feature: most of those getting sick and dying from the pneumonia-causing virus are elderly men, data compiled by Bloomberg show. In contrast, earlier this week, a 4-year-old boy in Beijing became the first reported case of an infection without illness.
The Geneva-based WHO started a joint assessment panel with Chinese health authorities comprising 15 foreign and Chinese specialists that will visit hospitals in the affected cities, O’Leary said. The panel “will mainly investigate the sources of the virus” and will provide recommendations and a risk control plan at a later time, he said.
Nancy Cox, director of the flu division at the U.S. Centers for Disease Control and Prevention in Atlanta; Anne Kelso, director of a WHO flu research center in Melbourne, Australia; Malik Peiris, chairman of virology at the University of Hong Kong; and Angus Nicoll, head of the Stockholm-based European Centre for Disease Prevention and Control’s flu program, were to arrive in China earlier this week, according to two people familiar with the matter.
An “important area of suspicion” about human exposure to the H7N9 virus is in markets where live butchering of chickens is carried out, said Feng Zijian, director of public health emergency at the Chinese Center for Disease Control and Prevention.
Fowl in these markets are usually defeathered by being plunged into vats of spinning boiling water, which could create aerosols that are inhaled by people passing by, Feng said, according to a transcript posted on the agency’s website yesterday.
While it isn’t possible to determine if sustained person- to-person transmission of the H7N9 flu strain is possible, “if the virus is to change, there might be risks,” O’Leary said at today’s briefing.
A new flu strain against which nobody has natural immunity could touch off a pandemic if it’s capable of spreading easily and efficiently among people, such as what happened in 2009, after a novel strain of swine flu, called H1N1, emerged in Mexico.
“We never know when the pandemic influenza will arrive and there might be false alarms, but we are still in early investigations, so there’s no reason to panic or be overly concerned,” O’Leary said.
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