China's H7N9 cases spike, led by infections in Beijing

Poultry market China
Poultry market China

josephbergen / Flickr cc

After several weeks of declining H7N9 avian influenza activity, China's cases are rising again, partly related to a recent spurt of local infections in Beijing, an area that usually doesn't see many cases and is located north of the main hot spots.

Hong Kong's Centre for Health Protection (CHP), citing mainland health officials, said today that 27 more cases, 7 of them fatal, were reported from Apr 14 to Apr 20. Seven of them are in Beijing. Cases peaked in January and February, but over the past few weeks, new infections had declined to about 15 a week.

New cases in 10 provinces

Of the latest patients, 21 had known exposure to poultry, poultry markets, or market stalls. Ages range from 34 to 79, and 16 are men and 11 are women.

China is still in the fifth and largest H7N9 wave, and patients are from a much wider geographic range, as has been the recent pattern. The latest cases include residents from Beijing and 10 provinces.

Beijing sees late-season spike

Until a few weeks ago, Beijing had reported only three H7N9 cases, all imported from other provinces. Since then, its cases have soared to 13, mostly due to infections contracted after exposure to live poultry. The cases include a two-person cluster, and both patients had a common exposure history.

A statement yesterday from the Beijing Center for Disease Control, translated and posted by Avian Flu Diary, an infectious disease news blog, addressed the city's recent uptick. It said 7 of the 13 cases during this wave are local and 6 were imported.

All of the local case-patients had live-poultry or poultry-market exposure, three of them having contact with dead poultry. Another change during this wave of H7N9 activity has been the detection of a highly pathogenic form of H7N9 in poultry in some parts of China; it's unclear if high-path H7N9 has been found in Beijing poultry.

China has now reported at least 639 cases in the unprecedented fifth H7N9 wave, at least 186 of them fatal.

The World Health Organization (WHO) said yesterday in an update that since 2013 when the virus was first detected in humans, it has received reports of 1,393 cases. The update didn't include the cases noted by the CHP today.

See also:

Apr 21 CHP statement

Apr 20 Avian Flu Diary post

Apr 20 WHO H7N9 update

This week's top reads