Hong Kong's CHP has published their latest weekly avian influenza report, which adds 24 new H7N9 cases from the Mainland - and 1 imported case in Hong Kong - to last week's tally.
Nearly all of these Mainland cases appear to be part of the batch reported last Friday by the NHFPC (see HK CHP Notified Of 22 Additional H7N9 Cases From Mainland China), all of which reportedly had onset of illness between February 19th and March 3rd.
Given the logistics involved in a country the size of China, it is not unexpected to see a lag between onset of illness, diagnosis, the notification of Beijing, and the public release of information. Some provinces may be slower to report than others, and so we see a certain amount of `back filling' of data in these weekly reports.
Hong Kong now reports 501 Mainland cases since the start of this 5th wave (plus 5 in Hong Kong, 2 in Macao & 1 in Taiwan). We continue to see a steady stream of cases reported by local provinces and Chinese media, suggesting this year's epidemic season is far from over.
Since only those those ill enough to be hospitalized are generally tested, this official count is assumed to represent only a fraction of the full burden of the disease (see Beneath The H7N9 Pyramid).
The full report (which runs 10 pages) is well worth downloading and reading, as it contains updates not only on avian flu activity in Mainland China, but around the world. While it doesn't not yet show it, we are aware of at least 2 H5N1 cases (1 fatal) in Egypt this year.
Avian Influenza Report
Avian Influenza Report is a weekly report produced by the Respiratory Disease Office, Centre for Health Protection of the Department of Health. This report highlights global avian influenza activity in humans and birds.
VOLUME 13, NUMBER 10
Reporting period: March 5, 2017 – March 11, 2017 (Week 10)
(Published on March 14, 2017)
1. Since the previous issue of Avian Influenza Report (AIR), there were 24 new human cases of avian influenza A(H7N9) reported by Mainland China health authorities in Henan (4 cases), Jiangxi (4 cases), Guangxi (3 cases), Sichuan (3 cases), Fujian (2 cases), Guizhou (2 cases), Hunan (2 cases), Jiangsu (2 cases), Chongqing (1 case) and Hubei (1 case). In addition, The Centre for Health Protection (CHP) of the Department of Health confirmed one imported human case of avian influenza A(H7N9). This case is the fifth case in Hong Kong this winter and the twenty-first case in Hong Kong. Since March 2013 (as of March 11, 2017), there were a total of 1307 human cases of avian influenza A(H7N9) reported globally. Since October 2016 (as of March 11, 2017), 501 cases have been recorded in Mainland China.
2. Since the previous issue of AIR, there were no new human cases of avian influenza A(H5N6). Since 2014 (as of March 11, 2017), 16 human cases of avian influenza A(H5N6) were reported globally and all occurred in Mainland China. The latest case was reported on December 1, 2016.
3. There were no new human cases of avian influenza A(H5N1) reported by the World Health Organization (WHO) in 2017. From 2011 to 2015, 32 to 145 confirmed human cases of avian influenza A(H5N1) were reported to WHO annually (according to onset date). In 2016, there have been 10 cases in Egypt.*
While we've seen a record number of H7N9 human infections this year, and the emergence of a new HPAI strain, so far we've not seen any indication of sustained or efficient human-to-human transmission of the virus.
Bird to human transmission still appears to be the primary route of infection.
That said, the virus continues to evolve (see MWR:Increase in Human Infections with Avian Influenza A(H7N9) In China's 5th Wave), and so governments around the world continue to closely monitor the situation (see CDC Updated Risk Assessment On China's H7N9 Virus).