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ARCHIVE H7N9 situation update

17 May 2017, 17:00 hours; Rome

The next update will be issued on 24 May 2017

Disclaimer

Information provided herein is current as of the date of issue. Information added or changed since the last H7N9 situation update appears in red. Human cases are depicted in the geographic location of their report. For some cases, exposure may have occurred in one geographic location but reported in another. For cases with unknown onset date, reporting date was used instead. FAO compiles information drawn from multiple national (Ministries of Agriculture or Livestock, Ministries of Health, Provincial Government websites; Centers for Disease Prevention and Control [CDC]) and international sources (World Health Organization [WHO], World Organisation for Animal Health [OIE]) as well as peer-reviewed scientific articles. FAO makes every effort to ensure, but does not guarantee, accuracy, completeness or authenticity of the information. The designation employed and the presentation of material on the map do not imply the expression of any opinion whatsoever on the part of FAO concerning the legal or constitutional status of any country, territory or sea area, or concerning the delimitation of frontiers.

 

 Overview

Situation: Influenza A(H7N9) virus with pandemic potential.
Country: China; three human cases originated in China and were reported in Malaysia (1) and Canada (2).
Number of human cases: 1508 confirmed; 577 deaths (since February 2013).

Number of new findings in birds or the environment since last update (10 May 2017): 1.
Number of new human cases since last update (10 May 2017): 22
.
Provinces/municipalities: Beijing, Chongqing, Shanghai and Tianjin Municipalities; Anhui, Fujian, Gansu, Guangdong, Guizhou, Hebei, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Qinghai, Shaanxi, Shanxi, Shandong, Sichuan, Taiwan, Yunnan and Zhejiang Provinces; Hong Kong SAR; Macao SAR, Guangxi, Ningxia Hui, Tibet and Xinjiang Uyghur Autonomous Regions; Sabah (Malaysia); British Columbia (Canada).
Animal/environmental findings: around 2,500 virological samples from the environment, chickens, pigeons, ducks and a tree sparrow tested positive; positives mainly from live bird markets, vendors and some commercial or breeding farms.

Highly pathogenic virus findings: The H7N9 highly pathogenic avian influenza virus was detected in a total of 43 poultry or environmental samples (32 chickens, 1 duck and 10 environmental samples) from 23 live bird markets (LBMs) in:Fujian (Longyan City), Guangdong (Dongguan, Guangzhou, Huizhou, Lufeng, Meijiang, Meizhou, Zhongshan Cities and Haifeng County), Hunan (Chenzhou City) and Guangxi (Guilin City) Provinces; and from 4 farms in: Guangxi (Guilin City), Hebei (a chicken layer farm [reference]), Henan (a chicken layer farm in Pingdingshan City [reference]) and Hunan (backyard in Chenzhou City and a large chicken layer farm in Yongzhou City [reference]) Provinces.

Out of the 1508 confirmed human cases, H7N9 virus isolates from three human cases (two from Guangdong and one from Taiwan Provinces) were found to be highly pathogenic for chickens.

FAO actions: liaise with China and partners, monitor situation, monitor virus evolution, conduct market chain analysis, risk assessment, surveillance guidance and communication.

Map 1. Human cases and positive findings in birds or the environment

Human cases and positive findings in birds or the environment
Click to enlarge - Note: Human cases are depicted in the geographic location where they were reported; for some cases, exposure may have occurred in a different geographic location. Precise location of 24 human cases in Anhui (2), Beijing (2), Guangdong (1), Guangxi (1), Hebei (3), Hunan (1), Hubei (2), Jiangsu (1), Jiangxi (6), Sichuan (2) and Zhejiang (3) Provinces are currently not known, these cases are therefore not shown on the map.

 

 

 Situation update

Animals

  • 16 May, Shanxi: While no virological positive samples from animals have ever been reported, a first H7N9 human case was confirmed in Datong City, with onset on 1 May [reference].
  • 12 May, Henan: The National Avian Influenza Reference Laboratory confirmed a H7N9 outbreak observed on 3 May in a layer chicken farm in Lushan County, Pingdingshan City. About 7,500 chickens showed clinical signs consistent with avian influenza and 5,770 died; 77,040 birds were culled [reference].

Figure 1. Number of positive virological samples from birds or the environment, by province and origin as of 17 May 2017. Information provided corresponds to both high and low pathogenic H7N9 viruses.

Number of positive virological samples from birds or the environment, by province* and origin
Click to enlarge


Humans

  • Since the last update (10 May 2017), 22 new human cases have been reported in Hebei (6), Henan (3), Sichuan (3), Beijing (2), Gansu (1), Hubei (1), Hunan (1), Jiangsu (1), Shandong (1), Shanxi (1), Tianjin (1), Zhejiang (1).

Figure 2. Number of officially reported human cases since February 2013 as of 17 May 2017. Information provided corresponds to both high and low pathogenic H7N9 viruses.

Number of officially reported human cases since February 2013
Click to enlarge

Figure 3. Incidence of officially reported human cases by month, based on onset date as of 17 May 2017. Information provided corresponds to both high and low pathogenic H7N9 viruses.

Incidence of officially reported human cases by week, based on onset date
Click to enlarge - Note: For cases with unknown onset dates from wave 1 (n=7), wave 2 (n=2), wave 3 (n=146), wave 4 (n= 27) and wave 5 (n=166) reporting dates were used instead.


Publications

  • In addition to the surveillance findings by MoA and MoH, 1,728 virologically positive samples have also been reported in 12 peer-reviewed articles (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12). A total of 71,920 samples have been collected in these studies since April 2013, of which 1,728 (2.4%) were positive for H7N9 (1,215 environmental samples, 501 chickens, 1 goose and 1 tree sparrow).
  • A biological characterization of the H7N9 HPAI isolated from humans has been performed. The insertion of four amino acids (KRTA) at the haemagglutinin (HA) cleavage site enabled trypsin-independent infectivity of this virus. Although maintaining dual receptor-binding preference, its HA antigenicity was distinct from low-pathogenic avian influenza A(H7N9). The neuraminidase substitution R292K conferred a multidrug resistance phenotype. [reference].
  • An article submitted on 31 October 2016 and published recently in Chinese describes pulmonary pathology of three cases of human infection with highly pathogenic H7N9 avian influenza virus [reference].

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