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ARCHIVE H7N9 situation update

05 June 2019, 17:00 hours; Rome

The next update will be issued on 03 July 2019

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 (08 May 2019): 0

New human cases since last update (08 May 2019): 0

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

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. Regarding the fifth period (October 2016-September 2017), precise location of 20 human cases in Guangdong (1), Guangxi (1), Hebei (3), Hunan (1), Hubei (1), Jiangsu (1), Jiangxi (5), Zhejiang (2) and unknown (5) 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 58 poultry or environmental samples (46 chickens, 2 duck and 10 environmental samples); H7N9 virus isolates from 32 human cases were found to be HPAI virus.

 

Table. Number of locations testing positive for H7N9 HPAI virus (n=43) in birds and/or the environment, by province and sampling site as of 05 June 2019.

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 1

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 (08 May 2019), 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.

Figure 1. Number of positive virological samples from birds or the environment, by province and origin as of 05 June 2019

Number of positive virological samples from birds or the environment, by province and origin as of 03 April 2019. Data include both high and low pathogenic H7N9 viruses
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 05 June 2019. Samples from the same location and time are grouped.

Figure 3. Distributions of low* and highly pathogenic H7N9 virologically positive samples (nLPAI=280; nHPAI=50)

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. collected from birds or the environment, by sample origin between October 2016 and 05 June 2019. Samples from the same origin, location and time are grouped.

 

Humans

  • Since the last update (08 May 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 05 June 2019

Phylogenetic relationships of A(H7) Eurasian HA genes, including Chinese-origin H7N9
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 2014 (beginning of period 3) to 05 June 2019

Phylogenetic relationships of A(H7) Eurasian HA genes, including Chinese-origin H7N9
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

  • Su K., Ye S., Li Q., Xie W., Yu H., Qi L., […], & Li Y. Influenza A(H7N9) Virus Emerged and Resulted in Human Infections in Chongqing, Southwestern China since 2017. International Journal of Infectious Diseases 81 (April 1, 2019): 244–50. [reference]. This study aimed to describe the epidemiological characteristics of the first epidemic in Chongqing Province. Since the confirmation of the first patient infected with influenza A(H7N9) virus on 5 March 2017, nine patients had been identified within four months in Chongqing. All patients reported exposure to live chickens. Phylogenetic analysis indicated that the viruses isolated in Chongqing belonged to the Yangtze River Delta lineage and resembled those circulating in Jiangsu and Anhui provinces between late 2016 and early 2017. LPMs and poultry related workers were impacted the most.
  • Yu D., Xiang G., Zhu W., Lei X., Li B., Meng Y., & Wang D. The re-emergence of highly pathogenic avian influenza H7N9 viruses in humans in mainland China, 2019. Eurosurveillance 24, no. 21, May 23, 2019. [reference]. This article describes the influenza A(H7N9) human case that occurred in Inner Mongolia in March 2019. Among H7N9 HPAI viral sequences, those recovered from the case and from environmental samples of a poultry slaughtering stall near the home formed a clade distinct from 2017 viral sequences. Several mutations possibly associated to antigenic drift occurred in the haemagglutinin gene, potentially warranting update of H7N9 vaccine strains.
  • Bangaru S., Lang S., Schotsaert M., Vanderven H.A., Zhu X., Kose N., & Crowe J.E.Jr. A Site of Vulnerability on the Influenza Virus Hemagglutinin Head Domain Trimer Interface. Cell, 2019 May 16;177(5):1136-1152.e18. [reference]. This publication describes the discovery of a naturally occurring human antibody, FluA-20, that recognizes a new site of vulnerability on the hemagglutinin (HA) head domain and reacts with most influenza A viruses. The Ab rapidly disrupted the integrity of HA protein trimers, inhibited cell-to-cell spread of virus in culture, and protected mice against challenge with viruses of H1N1, H3N2, H5N1, or H7N9 subtypes when used as prophylaxis or therapy. The FluA-20 Ab has uncovered an exceedingly conserved protective determinant in the influenza HA head domain trimer interface that is an unexpected new target for anti-influenza therapeutics and vaccines.
  • Wang W.H., Erazo E.M., Ishcol M.R.C., Lin C.Y., Assavalapsakul W., Thitithanyanont A., & Wang S.F. Virus-Induced Pathogenesis, Vaccine Development, and Diagnosis of Novel H7N9 Avian Influenza A Virus in Humans: A Systemic Literature Review. Journal of International Medical Research, May 8, 2019. [reference]. This systemic review summarizes H7N9 virus-induced pathogenesis, vaccine development, and current diagnostic assays for H7N9 AIV infection in humans.
  • Zhang W., Zhao K., Jin J., He J., Zhou W., Wu J., Tang R., Ma W., Ding C., Liu W., Zhang L., & Gao R. A Hospital Cluster Combined with a Family Cluster of Avian Influenza H7N9 Infection in Anhui Province, China. Journal of Infection 79, no. 1; July 1, 2019: 49–55. [reference]. This study aimed at identifying human-to-human transmission of H7N9 avian influenza virus within a hospital cluster combined with a family cluster. Exposure on a poultry farm was the source of infection for the index case, while airborne transmission may have resulted in both hospital and family clusters.

 FAO actions

  • Report of the WHO Vaccine Composition Meeting – February 2019 [link]
  • FAO published a risk assessment update entitled, “Chinese-origin H7N9 avian influenza: spread in poultry and human exposure” [link]
  • A webinar entitled “Pros and cons of avian influenza 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