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ARCHIVE H7N9 situation update

03 April 2019, 17:00 hours; Rome

The next update will be issued on 08 May 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: 1,567 confirmed; 615 deaths (since February 2013).
New findings in birds / environment since last update (06 March 2019): 1

New human cases since last update (06 March 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=44) in birds and/or the environment, by province and sampling site as of 03 April 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

Liaoning Province reported an H7N9 highly pathogenic avian influenza (HPAI) outbreak in ornamental peacocks raised in Jinzhou Zoo in Linghe District, Jinzhou City. There were 394 ornamental/exhibition birds, of which 9 peacocks got sick and died. The local authorities culled 191 birds in accordance with the relevant plans and technical requirements for avian influenza prevention and control [reference1, reference2]. The Jinzhou Zoo is located right next to the Xiangying Park where a lake is present, potentially hosting susceptible bird species.

 

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 03 April 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 03 April 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 03 April 2019. Samples from the same origin, location and time are grouped.

 

Humans

  • Since the last update (06 March 2019), no human cases were reported.
  • For detailed informationon human cases, please refer to WHO report.

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

 

For a phylogenetic tree on relationships of A(H7) Eurasian HA genes, including H7N9 isolates, please click here. Acknowledgements: WHO report ‘Antigenic and genetic characteristics of zoonotic influenza viruses and development of candidate vaccine viruses for pandemic preparedness’ – February 2019 [reference].

 

 Publications

  • Pu, Z., Yang, J., Shen, X., Irwin, D.M., & Shen, Y. Human-isolated H7N9 obtained internal genes from duck and human influenza viruses. The Journal of Infection, 2019 March 14. pii: S0163-4453(19)30077-5. [reference]. In this study, available H7N9 sequences were analyzed to detect potential novel reassortments. The authors suggest that three human H7N9 isolates attained internal genes from duck and human AIVs.
  • Jiang, W., Hou, G., Li, J., Peng, C., Wang, S., Liu, S., Zhuang, Q., Chen, J., & Liu, H. Prevalence of H7N9 subtype avian influenza viruses in poultry in China, 2013-2018. Transboundary and Emerging Diseases, 2019 March 23. [reference]. Prevalence of H7N9 AIVs in China was assessed over time based on results from systematic large-scale surveillance in poultry during 2013-2018. Findings indicate that the poultry vaccination campaign implemented in 2017 not only significantly decreased the prevalence of H7N9 AIVs in poultry but also effectively prevented human infection with H7N9 viruses.
  • Zheng, H., Xinhua, O., Rusheng, Z., Dong, Y., Lingzhi, L., Ruchun, L., & Biancheng, S. Evolved avian influenza virus (H7N9) isolated from human cases in a middle Yangtze River city in China, from February to April 2017. Heliyon, 5(3), e01253. [reference]. Seven human cases of avian influenza A H7N9 virus infection were reported from February to April 2017 in Changsha City. Phylogenetic analysis indicates that these H7N9 viruses were of avian origin, and belong to the Yangtze River Delta lineage. The proportion of PB2 Ala588Val substitutions in virus genomes significantly increased over the years, from 0.8 % (1 of 128 cases) to 84.9 % (275 of 324 cases), which may be an indication for enhanced infectivity for mammals.
  • Chen, Y., & Wen, Y. Spatiotemporal Distributions and Dynamics of Human Infections with the A H7N9 Avian Influenza Virus. Computational and Mathematical Methods in Medicine, 2019 February 7. [reference]. This study aims at analyzing the spatiotemporal distributions and dynamics of A(H7N9) human infections in China. An eco-epidemiological model was built to explore different disease control measures by numerical simulations. Simulations indicate that measures like vaccination of poultry and stopping live poultry transactions are primary factors for disease control.

 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” [reference]
  • 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