Researchers Say #H7N9 Incubation Period is about 3 Days

ProMED:  Avian influenza, human (88): China, H7N9, relative severity
Published Date: 2013-06-24 19:18:24
Archive Number: 20130624.1789634

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Date: Mon 24 Jun 2013
Source: South China Morning Post, Agence France-Presse report [edited]
http://m.scmp.com/news/china/article/1267754/h7n9-bird-flu-kills-about-third-hospitalised-patients-study-finds


The H7N9 bird flu that hit China this year [2013] killed over a third of hospitalised patients, putting the severity of the infection between that of swine A(H1N1) flu and the A(H5N1) avian virus, said researchers on Monday [24 Jun 2013]. In a study published on Monday [24 Jun 2013], University of Hong Kong researchers analysed data from most of the 132 H7N9 avian influenza patients since its emergence 3 months ago. With reference to the H1N1 swine influenza outbreak in 2009, they estimated the overall death rate of H7N9 to be between 0.16 per cent to 2.8 per cent. The rate of fatality in hospitalised H7N9 patients was 36 per cent, compared to 5 per cent to 20 per cent in the case of swine flu patients and 65 per cent in H5N1 patients in China.

"One-third hospital fatality is not a small figure. Killing of chickens and market closures may still be needed when the epidemic reappears. I believe these measures should not be relaxed," said Professor Gabriel Leung, director of the university's Public Health Research Centre who announced the findings on Monday [24 Jun 2013]. They warned watchdogs not to take comfort from a lull in new infections, as the virus may reappear in the autumn.
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"The warm season has now begun in China, and only one new laboratory-confirmed case of H7N9 in human beings has been identified since 8 May 2013. If H7N9 follows a similar pattern to H5N1, the epidemic could reappear in the autumn," they wrote. "This potential lull should be an opportunity for discussion of definitive preventive public health measures, optimisation of clinical management, and capacity building in the region in view of the possibility that H7N9 could spread beyond China's borders."

The team also estimated the virus's incubation period -- the time between infection and the onset of symptoms -- at about 3 days, shorter than previous estimates.

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