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ARCHIVE LATEST H7N9 situation update

28 March 2018, 17:00 hours; Rome

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: 1,625 confirmed; 622 deaths (since February 2013).
New findings in birds / environment since last update (28 February 2018): 6

New human cases since last update (28 February 2018): 0

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 32 human cases were found to be HPAI virus.

 

Table. Number of locations testing positive for H7N9 HPAI virus (n=39) in birds and/or the environment, by province and sampling site as of 28 March 2018.

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

2

0

0

2

Tianjin

0

1

0

0

1

Unknown

0

0

0

1

1

TOTAL

26

11

1

1

39

 

*LBM: live bird market

 

 

 Situation update

Animals

  • 22 March 2018, Ministry of Agriculture, China published the results of the national animal H7N9 surveillance and post-vaccination monitoring for the month of February 2018. The overall post-vaccination monitoring result* from 28 provinces was 86.85%**. Out of the 49,113 virology samples collected from 26 provinces, five samples tested positive for H7N9: two chicken samples in Anhui Province, two duck samples in Fujian Province and one chicken sample in Hubei Province, all located in live bird markets. [reference].
    *antibody titre ≥ 24 as required by the MoA regulation.
    **proportion of poultry samples which achieved required immunity level.
  • 17 February 2018, Shaanxi Province: An H7N9 outbreak occurred in a layer chicken farm in Wang Yi District, Tongchuan City, where 1,000 birds were found sick and 810 died [reference]. An investigation conducted by the local veterinary authority found that the sick layer chickens were only vaccinated once last September, instead of twice with a month interval as per official H7N9 vaccination procedure [unpublished information through FAO ECTAD China].

Animal/environmental findings: Since 4 April 2013 around 2500 virological samples from the environment, chickens, pigeons, ducks, 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 28 March 2018. 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=238; nHPAI=39) collected from birds or the environment, by sampling location, between October 2016 and 28 March 2018. 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=274; nHPAI=45) collected from birds or the environment, by sample origin between October 2016 and 28 March 2018. 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 (28 February 2018), no new human case was reported.
  • For detailed informationon human cases, please refer to WHO report.

Figure 4. Number of officially reported human cases since February 2013 as of 28 March 2018. 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 from October 2013 (Beginning of wave 2) to 28 March 2018. 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 2 (n=2), wave 3 (n=146), wave 4 (n=27) and wave 5 (n=55), reporting dates were used instead.

Figure 6. Phylogenetic relationships of different A(H7N9) virus isolates from 2013 until September 2017

Incidence of officially reported human cases by week, based on onset date
Click to enlarge - Note: The candidate vaccine viruses available or in preparation appear in blue. The scale bar represents the number of substitutions per site. Bootstrap supports of topology are shown above selected nodes. Taken from WHO report ‘Antigenic and genetic characteristics of zoonotic influenza viruses and development of candidate vaccine viruses for pandemic preparedness’ – September 2017 [reference].

 

Publications  

  • Yao Y., Zhang T., Yang W., Shao Z., He B., Chen X., […], Chen J. Avian Influenza A (H7N9) Virus in a Wild Land Bird in Central China, Late 2015. Virologica Sinica, 2018 March 5. doi: 10.1007/s12250-018-0001-x. [reference]. This study reports the first isolation of H7N9 virus from a magpie-robin (Copsychus saularis) in Hubei Province, Central China, in late 2015. Genetic analysis showed that it shares a common ancestor with the poultry H7N9 viruses from Jiangxi in 2014.
  • Quan C., Shi W., Yang Y., Yang Y., Liu X., Xu W., [...], Bi Y. New threats of H7N9 influenza virus: the spread and evolution of highly and low pathogenic variants with high genomic diversity in Wave Five. Journal of Virology, 2018 Mar 21. pii: JVI.00301-18. doi: 10.1128/JVI.00301-18. [reference]. In this study, the geographical distribution, phylogeny and genetic evolution of 240 H7N9 viruses in Wave Five (October 2016 to September 2017), including 35 new isolates from patients and poultry in nine provinces, were analyzed together with strains from the first four waves. The enhanced prevalence and diverse genetic characteristics with mammalian-adapted and NAI-resistant mutations may have contributed towards increased numbers of human infections in Wave Five.
  • Qi X., An X., Jiao Y., Yu H., Xu K., Cui L., […], Bao C. Co-circulation of multiple genotypes of influenza A (H7N9) viruses in eastern China, 2016-2017. Archives of Virology. 2018 March 14. doi: 10.1007/s00705-018-3800-3. [reference]. In this study, 41 H7N9 viruses from patients and live-poultry markets were isolated and full-sequenced to further elucidate the genetic features of viruses of the fifth wave in Jiangsu province; and the HA genes of other H7N9 viruses from humans (n = 91) and the environment (n = 32) were also sequenced (data not shown). Phylogenetic analysis revealed substantial genetic diversity in the internal genes, and 18 genotypes were identified from the 41 H7N9 virus strains. Data also revealed that the 41 isolates from Jiangsu contained mutations in their haemagglutinin protein (HA), which may increase the ability of these viruses to bind the human receptor. Four basic amino acid insertions were not observed in the HA cleavage sites of 167 H7N9 viruses from Jiangsu.

FAO actions:

  • FAO published a risk assessment update entitled, “Chinese-origin H7N9 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