Tuesday, May 02, 2017

HK CHP Avian Flu Report Week 17


Hong Kong's Centre For Health Protection has published their latest weekly avian influenza report which details the 17 cases reported last Friday by the Mainland's NHFPC.  While a substantial drop from the previous week (n=27), this remains an elevated number for this late in the spring.
Of note, of the 24 Mainland provinces and municipalities that have reported H7N9 cases, half (n=12) have more than doubled their previous (4 year) case count, while 5 (plus Macao) have reported cases for the first time this year.

I've color coded this week's case list from Hong Kong's CHP, with yellow reflecting a doubling of cases during the past 6 months, and orange designating first time outbreaks.

Credit HK CHP - Modified with Color Coding

 Some excerpts from this week's report follows, then I'll return with a bit more.

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.

Reporting period: April 23, 2017 – April 29, 2017 (Week 17)
(Published on May 2, 2017)


  1. Since the previous issue of Avian Influenza Report (AIR), there were 17 new human cases of avian influenza A(H7N9) reported by Mainland China health authorities in Sichuan (5 cases), Beijing (2 cases), Guangdong (2 cases) Shandong (2 cases), Chongqing (1 case), Fujian (1 case), Gansu (1 case), Henan (1 case), Hunan (1 case) and Jiangsu (1 case). Since March 2013 (as of April 29, 2017), there were a total of 1439 human cases of avian influenza A(H7N9) reported globally. Since October 2016 (as of April 29, 2017), 633 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 April 29, 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. Since the previous issue of AIR, there were no new human cases of avian influenza A(H5N1). From 2011 to 2016, 10 to 145 confirmed human cases of avian influenza A(H5N1) were reported to the World Health Organization (WHO) annually (according to onset date). In 2017, there have been so far two cases in Egypt.*

               (Continue . . . .)

The age-skewing of H7N9 cases towards the elderly continues with only 1 case under the age of 40 - a four year-old girl who is listed with mild illness.   
While we've seen a smattering of children, teenagers, and young adults infected with this virus, the average age of patients has consistently stayed in the mid-to-low 50s, with younger patients usually (but not always) experiencing  milder illness. 
Whether younger people are really less likely to be infected - or simply tend to have milder illness, and are therefore less likely to be tested and counted - remains unknown.
Case counts, conditions, and outcomes provided by China only represent those patients sick enough to seek treatment at a hospital, and who are subsequently tested and correctly diagnosed. 
It is assumed that the actual number of infections likely  runs much higher, although how much higher remains the $64 question (see Beneath The H7N9 Pyramid).  

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