H7N9 situation update

26 July 2017, 12:00 hours; Rome

The next update will be issued on 23 August 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: 1582 confirmed; 610 deaths (since February 2013).

Number of new findings in birds or the environment since last update (12 July 2017): 4
Number of new human cases since last update (12 July 2017): 2

Provinces/municipalities: Beijing, Chongqing, Shanghai and Tianjin Municipalities; Anhui, Fujian, Gansu, Guangdong, Guizhou, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Qinghai, Shaanxi, Shanxi, Shandong, Sichuan, Taiwan, Yunnan and Zhejiang Provinces; Hong Kong SAR, Macao SAR; Guangxi, Inner Mongolia, 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 48 poultry or environmental samples (37 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 8 farms in: Guangxi (Guilin City), Hebei (a chicken layer farm in Xingtai City [reference]), Henan (a chicken layer farm in Pingdingshan City [reference]), Hunan (backyard in Chenzhou City and a large chicken layer farm in Yongzhou City [reference]), Shaanxi (a chicken layer farm [reference]), Tianjin (a chicken layer farm [reference]), Inner Mongolia (two chicken layer farms in Hohhot and Baotou Cities [reference 1, reference 2] and Heilongjiang (a chicken layer farm in Shuangyashan City [reference]) Provinces.

Out of the 1582 confirmed human cases, H7N9 virus isolates from 25 human cases (including one from Taiwan Province) 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

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 30 human cases in Anhui (2), Beijing (2), Guangdong (1), Guangxi (1), Hebei (3), Hunan (1), Hubei (2), Jiangsu (2), Jiangxi (6), Sichuan (2), Zhejiang (3) and unknown (5) Provinces are currently not known, these cases are therefore not shown on the map.



Situation update

Animals

  • 26 July, Guangdong: Under the scope of a comprehensive ban on live poultry operation and trading, from 1 August 2017, markets in Qingyuan City downtown (Qingcheng District and Qingxin District) will no longer be allowed to sell live birds. Within the restricted area, "concentrated slaughter, cold chain distribution, and fresh sales" type poultry trading will be implemented where the public will only be able to buy fresh poultry meat [reference 1].
  • 25 July: MoA published the results of the national animal H7N9 surveillance for the month of June. 329,580 serum and 66,094 virological samples were collected from 19,413 locations in 28 provinces. 4 virology samples tested positive for H7N9 virus in Fujian (2 chickens from a market and a slaughterhouse in different cities), Shanghai (1 environmental sample from a market), Guangxi (1 chicken from a farm) Provinces. In addition, 3,018 serum samples tested positive for H7 antibodies in 17 provinces [reference].
Figure 1. Number of positive virological samples from birds or the environment, by province and origin as of 26 July 2017. Information provided corresponds to both high and low pathogenic H7N9 viruses.

Click to enlarge

Humans

  • Since the last update (12 July 2017), 2 new human cases have been reported in Jiangsu (1) and Yunnan (1).

Figure 2. Number of officially reported human cases since February 2013 as of 26 July 2017. Information provided corresponds to both high and low pathogenic H7N9 viruses.

Click to enlarge

Figure 3. Incidence of officially reported human cases by month, based on onset date as of 26 July 2017. Information provided corresponds to both high and low pathogenic H7N9 viruses.

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=189) reporting dates were used instead.

Publications

  • A review summarizes and compares the different waves of H7N9 regarding their epidemiology, pathogenesis, evolution, and characteristic features, and speculate on factors behind the recent increase in the number of human cases and sudden outbreaks in chickens. H7N9 infections represent an ongoing public health threat that has resulted in 1344 cases with 511 deaths as of 9 April 2017, highlighting the continued threat posed by the current poultry trade and live poultry market system in China. Until now, there have been five H7N9 influenza epidemic waves in China; however, the steep increase in the number of humans infected with H7N9 viruses observed in the fifth wave, beginning in October 2016, the spread into western provinces, and the emergence of highly pathogenic (HP) H7N9 influenza. outbreaks in chickens and infection in humans have caused domestic and international concern [reference].
  • Circulation of H7N9 in live poultry markets of China, the five waves of H7N9 infection in humans, recently identified drug resistant mutants, and potential antiviral drugs against H7N9 are discussed. The data reveal that the major source of H7N9 viruses are LPMs and the H7N9 virus is still circulating widely in China. It is concerning that the recent emergence of highly pathogenic H7N9 viruses may result in highly transmissible viruses in mammalian species. [reference].

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