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ARCHIVE H7N9 situation update

19 December 2017, 15:00 hours; Rome

The next update will be issued on 24 January 2018

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

Hazard: Influenza A(H7N9) virus with pandemic potential.
Country: China; imported cases in Malaysia (1) and Canada (2).
Number of human cases: 1,623 confirmed; 620 deaths (since February 2013).
New findings in birds / environment since last update (24 November 2017): 3

New human cases since last update (24 November 2017): 1

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 63 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 (38) Provinces are currently not known, these cases are therefore not shown on the map.

 

Provinces/municipalities affected: 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 (China); Sabah (Malaysia); British Columbia (Canada).

Highly pathogenic virus findings: Since 10 January 2017, highly pathogenic avian influenza (HPAI) type H7N9 virus was detected in a total of 54 poultry or environmental samples (42 chickens, 2 duck and 10 environmental samples); H7N9 virus isolates from 25 human cases were found to be HPAI virus.

 

Table. Number of locations testing positive for H7N9 HPAI virus (n=38) in birds and/or the environment, by province and sampling site as of 19 December 2017.

Province

LBM*

Farm

Backyard

Airport

Total

Anhui

0

1

0

0

1

Fujian

1

0

0

0

1

Guangdong

22

0

0

0

22

Guangxi

0

1

0

0

1

Hebei

0

1

0

0

1

Heilongjiang

0

1

0

0

1

Henan

0

1

0

0

1

Hunan

3

1

1

0

5

Inner Mongolia

0

2

0

0

2

Shaanxi

0

1

0

0

1

Tianjin

0

1

0

0

1

Unknown

0

0

0

1

1

TOTAL

26

10

1

1

38

 

*LBM: live bird market

 

 

 Situation update

Animals

  • 13 December, MoA published the results of the national animal H7N9 surveillance and post-vaccination monitoring for the month of November. Overall post-vaccination monitoring* result from 28 provinces was of 88.01%**, while vaccination in some provinces were not completed at the time of sampling;  and two chicken samples tested positive for H7N9 in Yunnan Province out of the 41,506 virology samples collected from 23 provinces [reference]. *: antibody titre ≥ 24 as required by the MoA regulation. **: ratio of poultry samples which achieved required immunity level.
  • 2 December, Yunnan Province: sick and dead chickens were reported in relation to the confirmed H7N9 human case in Kunming City on 30 November 2017. No information is available whether the deaths of  poultry was due to H7N9 infection [reference].
  • 2 December, Anhui Province: Hefei City announced a new plan to gradually withdraw live poultry trading from the city centre [reference].
  • 1 December, Guangdong Province: Huizhou City restricts live poultry trade in Zhongkai Hi-tech Industry Development District and promotes centralized slaughtering, cold chain distribution and fresh meat marketing from 20 December 2017[reference].
  • In November, Japan’s animal border control again detected a H7N9 virus strain in duck meat from China; No information is available about pathogenicity of the virus [reference].
  • 30 November, Guangdong Province: Zhongshan City closes all LBMs in the whole city from 1st to 3rd and from 15th to 17th (i.e. twice a month for three days each) from November 2017 to April 2018, and strengthen emptying cages, cleaning and disinfection. Random on site investigation on 11 live poultry markets will also be conducted [reference].
  • 28 November, MoA published the results of the national animal H7N9 surveillance for the month of October. A total of 19,936 virology samples have been collected from 27 provinces, no sample tested positive for H7N9 [reference].

Animal/environmental findings: Since 4 April 2013 around 2500 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.

Figure 1. Number of positive virological samples from birds or the environment, by province and origin as of 19 December 2017. Data include both high and low pathogenic H7N9 viruses.

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

Figure 2. Distributions of low* and highly pathogenic H7N9 virologically positive samples (nLPAI=224; nHPAI=38) collected from birds or the environment, by sampling location, between October 2016 and 19 December 2017 (wave 5). Samples from the same location and time are grouped.

Number of positive virological samples from birds or the environment, by province* and origin
Click to enlarge - *may contain unconfirmed HPAI at the time of publishing

Figure 3. Distributions of low* and highly pathogenic H7N9 virologically positive samples (nLPAI=260; nHPAI=44) collected from birds or the environment, by sample origin between October 2016 and 19 December 2017 (wave 5). Samples from the same origin, location and time are grouped.

Incidence of officially reported human cases by week, based on onset date
Click to enlarge - *may contain unconfirmed HPAI at the time of publishing

 

Humans

  • Since the last update (24 November 2017), one new human cases has been reported in Yunnan.
  • For detailed information on human cases, please refer to WHO's Disease Outbreak News

Figure 4. Number of officially reported human cases since February 2013 as of 19 December 2017. Data include both high and low pathogenic H7N9 viruses

Incidence of officially reported human cases by week, based on onset date
Click to enlarge

Figure 5. Incidence of officially reported human cases by month, based on onset date as of 19 December 2017. Both high and low pathogenic H7N9 viruses are included.

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=55), reporting dates were used instead.

 

Publications        

  • Jean Artois, et al. Changing Geographic Patterns and Risk Factors for Avian Influenza A(H7N9) Infections in Humans, China. Emerging Infectious Disease. 2018 Jan. doi: 10.3201/eid2401.171393 [reference]. An investigation on the effect of anthropogenic, poultry, and wetland variables on all epidemic waves showed that poultry predictor variables became much more important in the last two epidemic waves than they were previously, supporting the assumption of much wider H7N9 transmission in the chicken reservoir. Future range expansion of H7N9 to northern China may increase the risk of H7N9 epidemic peaks coinciding in time and space with those of seasonal influenza, leading to a higher risk of reassortments than before, although the risk is still low so far.
  • Wei Cheng, et al. Comparison of the three waves of avian influenza A(H7N9) virus circulation since live poultry markets were permanently closed in the main urban areas in Zhejiang Province July, 2014 –June, 2017.Influenza and Other Respiratory Viruses. 2017 Dec 15. doi: 10.1111/irv.12532. [reference]. A study showed that epidemiological characteristics of human cases infected with avian influenza A(H7N9) virus had generally remained unchanged since the massive closure of LPMs in the main urban area of Zhejiang province. The sudden increase of the number of H7N9 cases in the fifth wave were mainly attributed to the excessive cases reported from areas where LPMs were not permanently closed. 

FAO actions:

  • FAO published a risk assessment entitled, “Chinese-Origin H7N9 Highly Pathogenic Avian Influenza: Spread in poultry and human exposure” [reference]
  • FAO guidance and risk assessments are available on a dedicated website [link]
  • Liaise with China and partners, monitor situation, monitor virus evolution, conduct market chain analysis, risk assessment, surveillance guidance and communication.

FAO’s support to countries