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ARCHIVE H7N9 situation update

07 November 2018, 17:00 hours; Rome

The next update will be issued on 05 December 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: 1,567 confirmed; 615 deaths (since February 2013).
New findings in birds / environment since last update (05 September 2018): 0

New human cases since last update (05 September 2018): 0

Map. 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. Regarding the fifth wave (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 07 November 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

Liaoning 0 1 0 0 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

1

43

*LBM: live bird market

 

 Situation update

Animals

No new official information was reported by the Ministry of Agriculture and Rural Affairs, China since the last update of 03 October 2018.

Since the beginning of wave 7 (1 October 2018), 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, 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 07 November 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=246; nHPAI=43) collected from birds or the environment, by sampling location, between October 2016 and 07 November 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=280; nHPAI=49) collected from birds or the environment, by sample origin between October 2016 and 07 November 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 (03 October 2018), 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 07 November 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 07 November 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.


 Publications

  • Lu, J., Raghwani, J., Pryce, R., Bowden, T. A., Thézé, J., Huang, S., […], & Ke, C. (2018). Molecular Evolution, Diversity, and Adaptation of Influenza A(H7N9) Viruses in China. Emerging infectious diseases, 24(10), 1795-1805 [reference]. In this study, they investigated the evolution and adaptation of H7N9 viruses by analyzing available data and newly generated virus sequences isolated in Guangdong Province, China, during 2015–2017. Phylogenetic analyses showed that circulating H7N9 viruses belong to distinct lineages with differing spatial distributions. Results indicated that mutations in hemagglutinin occur primarily at sites involved in receptor recognition or antigenicity. Highly pathogenic strains likely emerged from viruses circulating in eastern Guangdong Province during March 2016 and are associated with a high rate of adaptive molecular evolution.
  • Wu, J., Ke, C., H.Y. Lau, E., Song, Y., Cheng, K.L., Zou, L., […], & Yen, H.L. Influenza H5/H7 Virus Vaccination in Poultry and Reduction of Zoonotic Infections, Guangdong Province, China, 2017–18. [reference]. Emerging Infectious Diseases, January 2019, 25(1). In this study, they compared the detection frequency of avian influenza H7 subtypes at live poultry markets in Guangdong Province, China, before and after the introduction of a bivalent H5/H7 vaccine in poultry. The vaccine was associated with a 92% reduction in H7 positivity rates among poultry and a 98% reduction in human H7N9 cases.
  • Sun, X., Belser, J.A., Pappas, C., Pulit-Penaloza, J.A., Brock, N., Zeng, H., […], Maines, T.R. Risk assessment of fifth-wave H7N9 influenza A viruses in mammalian models. Journal of virology, 2018 October 10. [reference]. In this study, a group of fifth-wave HPAI and LPAI viruses were evaluated for their ability to infect, cause disease, and transmit in small animal models. The ability of HPAI H7N9 viruses to cause more severe disease and to replicate in brain tissues in animal models as well as their ability to fuse at a lower pH threshold compared to LPAI H7N9 viruses suggest that the fifth-wave H7N9 viruses have evolved to acquire novel traits with the potential to pose a higher risk to humans.
  • Shibata, A., Okamatsu, M., Sumiyoshi, R., Matsuno, K., Wang, Z.J., Kida, H., Osaka, H., & Sakoda, Y. Repeated detection of H7N9 avian influenza viruses in raw poultry meat illegally brought to Japan by international flight passengers. Virology, 2018 November; 524:10-17. [reference]. H7N9 highly and low pathogenic avian influenza viruses (HPAIV and LPAIV, respectively) have been isolated from duck meat products that were brought illegally into Japan by flight passengers in their hand luggage. These H7N9 virus isolates were phylogenetically closely related to those prevailing in China. The hemagglutinin of the H7N9 HPAIV isolate was slightly different from those of the H7N9 LPAIV and older H7 strains.

 FAO actions

  • Report of the WHO Vaccine Composition Meeting September [link] and February 2018 [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 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