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H7N9 situation update

03 March 2021, 17:00 hours; Rome

The next issue will be distributed on 07 April 2021. If interested in a previous issue please send an email to EMPRES-Animal Health specifying the intended use of the document.

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: 1,568 confirmed; 616 deaths (since February 2013).
New findings in birds / environment since last update (03 February 2021):0
New human cases since last update (03 February 2021): 0

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

Human cases and positive findings in birds or the environment in China
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. Centroid geo-coordinates were used for H7N9 positive animal/environment samples where the precise geolocation is unknown.

 

Provinces/municipalities affected (since 2013): 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 66 poultry or environmental samples (46 chickens, 8 peacocks, 2 duck and 10 environmental samples); H7N9 virus isolates from 32 human cases were found to be HPAI virus.

 

Table 1. Number of locations testing positive for H7N9 HPAI virus (n=44) in birds and/or the environment, by province and sampling site as of 03 March 2021

Province

LBM*

Farm

Backyard

Others**

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

Liaoning 0 1 0 1 2

Inner Mongolia

0

2

0

0

2

Ningxia Hui

0

2

0

0

2

Shaanxi

0

2

0

0

2

Shanxi

0

1

0

0

1

Tianjin

0

1

0

0

1

Unknown

0

0

0

1

1

TOTAL

26

15

1

2 44

*LBM: live bird market; **Others include one airport and one zoo.

 

 Situation update

Animals

Since the last update (03 February 2021), no H7N9 outbreak or H7N9 positive animal or environment findings were reported.

 

Animal/environmental findings: Since 4 April 2013 around 2500 virological samples from the environment, chickens, pigeons, ducks, turkeys, peacocks, a tree sparrow and a magpie robin tested positive; positives mainly from live bird markets, vendors and some commercial or breeding farms.

 

Table 2. National H7N9 surveillance and post-vaccination monitoring results from January to November 2020 published by MARA, China

Reporting period

#serum samples collected from birds

Average post-vaccination monitoring immunization rate (target 70%)

#virological samples collected from birds and the environment

#H7N9 positive virological samples

January

72 845

96.24

17 536

0

February

107 409

94.27

34 501

0

March

127 074

95.05

42 190

0

April

104 650

95.34

24 017

0

May

180 261

95.59

21 961

3

June

221 577

95.77

31 183

0

July 166 193 92.32 43 404 0
August 110 926 96.08 17 053 0
September 106 163 95.67 16 410 0
October 78 070 95.15 11 647 14
November 168 938 95.87 32 425 0

Figure 1. Number of positive virological samples from birds or the environment, by province and origin as of 03 March 2021

Number of positive virological samples from birds or the environment, by province and origin
Click to enlarge - Data include both high and low pathogenic H7N9 viruses.

Figure 2. Distributions of low* and highly pathogenic H7N9 virologically positive samples (nLPAI=246; nHPAI=44).

Phylogenetic relationships of A(H7) Eurasian HA genes, including Chinese-origin H7N9
Click to enlarge - Note: * May contain unconfirmed HPAI at the time of publishing. Samples collected from birds or the environment, by sampling location, between October 2016 and 03 March 2021. Samples from the same location and time are grouped. Some data on H7N9 positive virological samples collected during national H7N9 surveillance could not be included due to absence of information on the sampling location and the sample origin.

Figure 3. Distributions of low* and highly pathogenic H7N9 virologically positive samples (nLPAI=281; nHPAI=50).

Distributions of low* and highly pathogenic H7N9 virologically positive samples (nLPAI=281; nHPAI=50)
Click to enlarge - Note: * May contain unconfirmed HPAI at the time of publishing. Samples collected from birds or the environment, by sample origin between October 2016 and 03 March 2021. Samples from the same origin, location and time are grouped. Some data on H7N9 positive virological samples collected during national H7N9 surveillance could not be included due to absence of information on the sampling location and the sample origin.

 

Humans

  • Since March 2019, no human cases were reported.
  • For detailed information on human cases, please refer to WHO report.

Figure 4. Number of officially reported human cases since February 2013, as of 03 March 2021

Number of officially reported human cases
Click to enlarge - Data include both high and low pathogenic H7N9 viruses.

Figure 5. Incidence of officially reported human cases by month, based on onset date from October 2015 (beginning of period 4) to 03 March 2021

Incidence of officially reported human cases by month, based on onset date
Click to enlarge - Note: For cases with unknown onset dates from period 2 (n=2), period 3 (n=146), period 4 (n=27) and period 5 (n=55), reporting dates were used instead. Both high and low pathogenic H7N9 viruses are included.

 

 Publications

  • Li, B., Xiang, G., He, J., Li, H., Xu, C., Yu, A., […], & Yu, D. H7N9 influenza virus surveillance in Gansu, China in 2017. Virus research, 296, 198335. Advance online publication. [reference]. This study analyses the results of H7N9 surveillance carried out in Gansu Province, China in 2017. During the monitoring five human cases with H7N9 virus infection were detected and a total of 88 environmental samples collected from March to June in poultry farms and live poultry markets tested positive for H7N9. The two human viruses were identified as LPAI viruses, and phylogenetic analysis showed that the viruses might be introduced into Gansu by two distinct trade routes.
  • Liu, L., Li, Z., Zhou, J., Lu, J., Li, X., Liu, J., Xiao, N., & Wang, D. The effect of single amino acid substitution at position 220 in the hemagglutinin glycoprotein on avian influenza H7N9 candidate vaccine virus. Virus genes, 10.1007/s11262-021-01827-y. Advance online publication. [reference]. In this study, the biological effects of a single substitution in the HA geneon receptor binding, neuraminidase (NA) activity, growth characteristics, genetic stability, and antigenicity were evaluated in two viruses constructed through reverse genetics. The results revealed both mutant viruses exhibited lower HA binding affinities to the two receptor type sand significant better growth characteristics compared to control virus. Importantly, both the substitutions conferred altered antigenicity to the mutant viruses.
  • Radvak, P., Kosikova, M., Kuo, Y. C., Li, X., Garner, R., Schmeisser, F., […], & Xie, H. Highly pathogenic avian influenza A/Guangdong/17SF003/2016 is immunogenic and induces cross-protection against antigenically divergent H7N9 viruses. NPJ vaccines, 6(1), 30. [reference]. The immunogenicity and efficacy of a H7 highly pathogenic avian influenza (HPAI) A/Guangdong/17SF003/2016 (GD/16)-extracted hemagglutinin (eHA) vaccine was assessed in this study. The vaccine induces robust H7-specific antibody responses in mice with a marked adjuvant antigen-sparing effect. Mice immunized with the vaccine were protected from the lethal LPAI and HPAI H7N9 challenges, in stark contrast to low antibody titers and high mortality in mice receiving adjuvanted LPAI H7 eHAs.

 FAO actions

  • WHO developed an online training course entitled Strengthening collaboration between human and animal health sectors for improved health security, freely available. The course covers the Tripartite Zoonosis Guide and associated tools in Module 2. [link]
  • FAO contributed to and participated in the Zoonotic Influenza Session of the WHO Vaccine Composition Meeting being held on 2-4 March 2021.
  • A Q&A on avian influenza with FAO’s Global Surveillance Coordinator is now available on the
  • FAO website. [link]
  • The Tripartite Joint Risk Assessment (JRA) Operational Tool to address zoonotic health threats at the animal-human-environment interface is now available online. [link]
  • As part of the OIE/FAO Network of Expertise on Animal Influenzas, FAO attended the Zoonotic Influenza Sessions of the WHO Vaccine Composition Meeting held from 29 September to 1 October 2020; Report – October 2020. [link]
  • A paper from FAO entitled “A literature review of the use of environmental sampling in the surveillance of avian influenza viruses” (Hood et al., 2020) was published in the Transboundary and Emerging Diseases journal. [link]
  • Report of the WHO Vaccine Composition Meeting – February 2020. [link]
  • The Tripartite Zoonoses Guide is now available in all UN languages. [link]
  • FAO published a risk assessment entitled, “Chinese-Origin H7N9 Avian Influenza: Spread in poultry and human exposure”. [reference]
  • A webinar entitled “Pros and cons on AI vaccination” was presented by Leslie Sims on 14 May 2018 with technical support from FAO HQ. A recording of the webinar is available. [link]
  • 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