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23 May 2018

#Avian #Influenza #H7N9 – #Situation #Update, as of 23 May 2018 (#FAO, edited)

          

Title:

#Avian #Influenza #H7N9 – #Situation #Update, as of 23 May 2018.

Subject:

Avian Influenza, H7N9 subtypes, poultry enzootic and human cases in China, monthly update.

Source:

Food and Agriculture Organization (FAO), full page: (LINK).

Code:

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Avian Influenza H7N9 – Situation Update, as of 23 May 2018

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The next update will be issued on 27 June 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:
    • 1,625 confirmed;
    • 623 deaths (since February 2013).
  • New findings in birds / environment since last update (25 April 2018):
    • 1
  • New human cases since last update (25 April 2018):
    • 0


Map 1. Human cases and positive findings in birds or the environment

Human cases and positive findings in birds or the environment

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|-- 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:

  • [China]
    1. Beijing,
    2. Chongqing,
    3. Shanghai and
    4. Tianjin Municipalities;
    5. Anhui,
    6. Fujian,
    7. Gansu,
    8. Guangdong,
    9. Guizhou,
    10. Hebei,
    11. Heilongjiang,
    12. Henan,
    13. Hubei,
    14. Hunan,
    15. Jiangsu,
    16. Jiangxi,
    17. Jilin,
    18. Liaoning,
    19. Qinghai,
    20. Shaanxi,
    21. Shanxi,
    22. Shandong,
    23. Sichuan,
    24. Yunnan and
    25. Zhejiang Provinces;
    26. Hong Kong SAR,
    27. Macao SAR;
    28. Guangxi,
    29. Inner Mongolia,
    30. Ningxia Hui,
    31. Tibet and
    32. Xinjiang Uyghur Autonomous Regions;
  • [Taiwan],
  • [Malaysia]
    • Sabah;
  • [Canada]
    • British Columbia.


Highly pathogenic virus findings:

  • Since 10 January 2017, highly pathogenic avian influenza (HPAI) type H7N9 virus was detected in a total of 57 poultry or environmental samples (45 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=42) in birds and/or the environment, by province and sampling site as of 23 May 2018.

[Province - LBM* – Farm – Backyard – Airport – Total]

  1. Anhui  - 0  - 1  - 0  - 0 – 1
  2. Fujian  - 1  - 0  - 0  - 0  - 1
  3. Guangdong  - 22  - 0  - 0  - 0 – 22
  4. Guangxi  - 0  - 1  - 0  - 0  - 1
  5. Hebei  - 0  - 1  - 0  - 0  - 1
  6. Heilongjiang  - 0  - 1  - 0  - 0  - 1
  7. Henan  - 0  - 1  - 0  - 0  - 1
  8. Hunan  - 3  - 1  - 1  - 0  - 5
  9. Inner Mongolia  - 0  - 2  - 0  - 0  - 2
  10. Ningxia Hui  - 0  - 2  - 0  - 0  - 2
  11. Shaanxi  - 0  - 2  - 0  - 0  - 2
  12. Shanxi  - 0  - 1  - 0  - 0  - 1
  13. Tianjin  - 0  - 1  - 0  - 0  - 1
  14. Unknown  - 0  - 0  - 0  - 1  - 1
    • TOTAL – 26 – 14 – 1 – 1 – 42
      • {*} LBM: live bird market


Situation update

  • Animals
    • 23 May 2018:
      • The Ministry of Agriculture (MoA), China published the results of the national animal H7N9 surveillance and post-vaccination monitoring for the month of April 2018.
      • The overall post-vaccination monitoring result* from 28 provinces was 91.26%**.
      • Out of the 40,192 virology samples collected from 24 provinces, none of the samples tested positive for H7N9. [reference].
        • {*} antibody titre ≥ 24 as required by the MoA regulation.
        • {**} proportion of poultry samples which achieved required immunity level.
    • 7 May 2018, Ningxia Hui Autonomous Region:
      • The second H7N9 HPAI outbreak within a month occurred on 25 April in a layer chicken farm in Yuanzhou District, Guyuan City, where 3,000 birds showed clinical signs and 2,200 died [reference1, reference2].
      • The first outbreak, also in a layer chicken farm, occurred in Wuzhong City (reported in the previous update).
      • Results for the month of April from the countrywide compulsory post-vaccination monitoring showed that 86.14% (963 out of 1,118) of the samples taken in Ningxia had the required immunity level [reference3].
    • 1 May 2018:
      • Seasonal suspension of live bird trade (including LBM closures) ended in Shanghai and Hefei cities [reference1, reference2].
  • 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.
  • Humans
    • Since the last update (25 April 2018), no new human case was reported.
    • For detailed information on human cases, please refer to WHO report.

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Figure 1. Number of positive virological samples from birds or the environment, by province and origin as of 23 May 2018. Data include both high and low pathogenic H7N9 viruses.

Number of positive virological samples from birds or the environment, by province* and origin

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|-- Click to enlarge –|

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Figure 2. Distributions of low* and highly pathogenic H7N9 virologically positive samples (nLPAI=245; nHPAI=42) collected from birds or the environment, by sampling location, between October 2016 and 23 May 2018. Samples from the same location and time are grouped.

Number of positive virological samples from birds or the environment, by province* and origin

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|-- Click to enlarge –| *may contain unconfirmed HPAI at the time of publishing

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Figure 3. Distributions of low* and highly pathogenic H7N9 virologically positive samples (nLPAI=279; nHPAI=48) collected from birds or the environment, by sample origin between October 2016 and 25 April 2018. Samples from the same origin, location and time are grouped.

Incidence of officially reported human cases by week, based on onset date

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|-- Click to enlarge –|

{*} may contain unconfirmed HPAI at the time of publishing

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Figure 4. Number of officially reported human cases since February 2013 as of 23 May 2018. Data include both high and low pathogenic H7N9 viruses

Incidence of officially reported human cases by week, based on onset date

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|-- Click to enlarge –|

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Figure 5. Incidence of officially reported human cases by month, based on onset date from October 2013 (Beginning of wave 2) to 23 May 2018. Both high and low pathogenic H7N9 viruses are included.

Incidence of officially reported human cases by week, based on onset date

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|-- 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.

For a phylogenetic tree of H7N9 viruses isolated please click here. Acknowledgements:WHO report ‘Antigenic and genetic characteristics of zoonotic influenza viruses and development of candidate vaccine viruses for pandemic preparedness’ – September 2017 [reference].


Publications 

  1. Slomka, M.J., Seekings, A.H., Mahmood, S., Thomas, S., Puranik, A., Watson, S., Byrne, A.M.P., Hicks, D., Nunez, A., Brown I.H. & Brookes, S.M. Unexpected infection outcomes of China-origin H7N9 low pathogenicity avian influenza virus in turkeys. Scientific Reports, 2018;8, Article number: 7322 doi:10.1038/s41598-018-25062-y. [reference].
    • This study is the first description of H7N9 LPAIV (A/Anhui/1/13) infection in turkeys, demonstrating efficient transmission to two additional rounds of introduced contact turkeys which all became infected during cohousing.
    • Mortality was observed in six out of of eight (75%) second-round contact turkeys, with systemic dissemination to many organs, but no accompanying mutation to highly pathogenic AIV.
    • The intravenous pathogenicity index score for a turkey-derived isolate (0.39) affirmed the LPAIV phenotype.
    • An amino acid change L235Q in the haemagglutinin gene occurred in directly infected turkeys and transmitted to the contacts, including those that died and the two birds surviving infection.
    • This polymorphism was indicative of a reversion from mammalian to avian adaptation for the H7N9 virus.
  2. Jiao, P., Song, Y., Huang, J., Xiang, C., Cui, J.,Wu, S., […], Liao, M. H7N9 Avian Influenza Virus is efficiently transmissible and induces an antibody response in chickens. Frontiers in Immunology, 2018;9:789. doi:10.3389/fimmu.2018.00789. [reference].
    • In this study, H7N9 viruses replicated in multiple organs of chicken and viral shedding persisted up to 30 days post-inoculation (DPI).
    • The viruses were efficiently transmitted between chickens through direct contact.
    • Chickens infected with H7N9 had high antibody levels throughout the entire observation period and their antibody response lasted for 30 DPI.
    • The viruses isolated from these birds had low pathogenicity in mice, produced little weight loss and only replicated in lungs.
  3. El-Shesheny, R., Feeroz, M.M., Krauss, S., Vogel, P., McKenzie, P., Webby, R.J. & Webster R.G. Replication and pathogenic potential of influenza A virus subtypes H3, H7, and H15 from free-range ducks in Bangladesh in mammals. Emerging Microbes and Infections. 2018;7(1):70. doi: 10.1038/s41426-018-0072-7. [reference].
    • Antigenicity, replication and pathogenicity of influenza viruses isolated from Tanguar Haor (wetlands in Bangladesh) were studied in the DBA/2J mouse model.
    • All viruses replicated in the lung without prior mammalian adaptation, and H7N1 and H7N9 viruses caused 100% and 60% mortality, respectively.
    • H7N5 viruses replicated only in the lungs, whereas H7N1 and H7N9 viruses also replicated in the heart, liver, and brain.
    • Replication and transmission studies in mallard ducks showed that H7N1 and H7N9 viruses replicated in ducks without clinical signs of disease and shed at high titers from the cloaca of infected and contact ducks.
    • [Note: the H7N9 virus mentioned here was isolated from domestic ducks.
    • [Note: the H7N9 virus mentioned here was isolated from domestic ducks in Bangladesh; the paper does not mention any genetic similarity to the Chinese-origin strain.]
  4. Zhou, X., Zheng, J., Ivan, F.X., Yin, R., Ranganathan, S., Chow, V.T.K., Kwoh, C.K. Computational analysis of the receptor binding specificity of novel influenza A/H7N9 viruses. BMC Genomics, 2018 May 9;19(Suppl 2):88. doi: 10.1186/s12864-018-4461-z. [reference].
    • In this study, the sequence pattern and structural characteristics of novel influenza A/H7N9 were systematically investigated using computational approaches.
    • The sequence analysis highlighted mutations in protein functional Commented [VS(16]: Old ones deleted, new ones added domains of influenza viruses.
    • Molecular docking and molecular dynamics simulation revealed that the hemagglutinin (HA) of A/Taiwan/1/2017(H7N9) strain enhanced the binding with both avian and human receptor analogs, compared to the previous A/Shanghai/02/2013(H7N9) strain.
  5. Wang, J., Su, N., Dong, Z., Liu, C., Cui, P., Huang, J.A., Chen, C., Zhu, Y., Chen, L. The Fifth Influenza A(H7N9) Epidemic: A Family Cluster of Infection in Suzhou City of China, 2016. International Journal of Infectious Diseases. 2018. pii: S1201-9712(18)34406-0. doi: 10.1016/j.ijid.2018.04.4322. [reference].
    • This study aimed to investigate the possibility of human-to-human transmission of the virus and examine the virological features of a family cluster of influenza A(H7N9) virus infection identified in Suzhou, China.
    • Sequencing viral genomes isolated from the two patients showed nearly identical nucleotide sequence, and genetically resembled the viral genome isolated from a chicken in the wet market where the index patient once visited.
    • All three influenza A(H7N9) viruses shared similar mutations in HA and a single basic amino acid at the cleavage site.
    • Human-to-human transmission of influenza A(H7N9) virus most likely occurred in this household.
  6. Liu, T., Kang, M., Zhang, B., Xiao, J., Lin, H., Zhao, Y., Huang, Z., Wang, X., Zhang, Y., He, J., Ma, W. Independent and interactive effects of ambient temperature and absolute humidity on the risks of avian influenza A(H7N9) infection in China. Science of the Total Environment, 2018;619-620:1358- 1365. doi: 10.1016/j.scitotenv.2017.11.226. [reference].
    • The study aimed to investigate the independent and interactive effects of ambient temperature (TM) and absolute humidity (AH) on H7N9 infection risks in China.
    • The individual information of all reported H7N9 cases and daily meteorological data in five provinces/municipality (Zhejiang, Jiangsu, Shanghai, Fujian, and Guangdong) in China during 2013-2016 were collected.
    • A total of 738 H7N9 cases were included in the present study.
    • Significantly nonlinear negative associations of TM and VP with H7N9 infection risks were observed in all cases.
    • The risks of H7N9 infection were higher in cold-dry days than other days.
    • The risky windows of H7N9 infection were different in the northern and southern areas.
  7. Vidaña, B., Dolz, R., Busquets, N., Ramis, A., Sánchez, R., Rivas, R., Valle, R., Cordón, I., Solanes, D., Martínez, J., Majó N. Transmission and immunopathology of the avian influenza virus A/Anhui/1/2013 (H7N9) human isolate in three commonly commercialized avian species. Zoonoses Public Health. 2018;65(3):312-321. doi: 10.1111/zph.12393. [reference].
    • This work evaluates the pathogenicity, transmissibility and local innate immune response of three avian species.
    • Muscovy ducks, European quails and SPF chickens were intranasally inoculated with the human H7N9 (A/Anhui/1/2013) influenza isolate.
    • None of the avian species showed clinical signs or macroscopic lesions, only mild microscopic lesions in the upper respiratory tract of quail and chickens.
    • Quail presented more severe histopathologic lesions and AIV positivity by immunohistochemistry.
    • In contrast, Muscovy ducks were resistant to disease.
    • In all species, viral shedding was higher in the respiratory than in the digestive tract.
    • Higher viral shedding was observed in quail, followed by chicken and ducks, which presented similar viral titres.
    • Efficient transmission was observed in all contact quail and half of the Muscovy ducks, while no transmission was observed between chicken.
    • All avian species showed viral shedding in drinking water throughout infection.


FAO actions:

  • 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

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Keywords: FAO; Updates; Avian Influenza; H7N9; Human; Poultry; China.

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