印刷

鳥インフルエンザA(H7N9)ウイルスによる感染事例に関するリスクアセスメントと対応

令和4年4月22日現在
国立感染症研究所

 

背景

 A型インフルエンザウイルス(H7N9亜型)(以下、H7N9ウイルス)は、家禽や野鳥で流行していた少なくとも3種類の異なるA型インフルエンザウイルスの遺伝子再集合体であると考えられ (Liu WJ, 2021)、ヒトに感染すると重篤な症状を来し得ることが報告されている(CDC, 2017)。中国における2018-2019年シーズン以降のH7N9ウイルスの感染者数は1例のみであった。2018-2019年シーズン以降の状況について疫学情報及びリスクアセスメントをアップデートする。

 

疫学的所見

 

1)事例の概要

 

2)臨床情報

3)感染源・感染経路

ウイルス学的所見

日本国内の対応

リスクアセスメントと今後の対応 

【日本人渡航者が感染するリスク】

【鳥インフルエンザH7N9ウイルスが持続的なヒト-ヒト感染を起こすリスク】

 

参考文献

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•国立感染症研究所. 鳥インフルエンザA(H7N9)ウイルスによる感染事例に関するリスクアセスメントと対応. 2014年1月29日. https://www.niid.go.jp/niid/ja/diseases/a/flua-h7n9/2276-a-h7n9-niid/4324-riskassess-140129.html.
•CDC, Update: Increase in Human Infections with Novel Asian Lineage Avian Influenza A(H7N9) Viruses During the Fifth Epidemic — China, October 1, 2016–August 7, 2017 Weekly / September 8, 2017 / 66(35);928–932
•CDC. Summary of Influenza Risk Assessment Tool (IRAT) Results. last reviwed on December 2, 2021. https://www.cdc.gov/flu/pandemic-resources/monitoring/irat-virus-summaries.htm.
•CDC. Interim Guidance for Specimen Collection, Processing, and Testing for Patients with Suspected Infection with Novel Influenza A Viruses Associated with Severe Disease in Humans. last reviewed on January 14, 2022. https://www.cdc.gov/flu/avianflu/h7n9/specimen-collection.htm.
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•FAO. H7N9 situation update. 02 March 2022. http://www.fao.org/ag/againfo/programmes/en/empres/h7n9/Situation_update.html
•He D, Gu M, Wang X, et al, Spatiotemporal Associations and Molecular Evolution of Highly Pathogenic Avian Influenza A H7N9 Virus in China from 2017 to 2021. Viruses. 2021; 13(12):2524. https://doi.org/10.3390/v13122524; Yin X, Deng G, Zeng X, et al. Genetic and biological properties of H7N9 avian influenza viruses detected after application of the H7N9 poultry vaccine in China. PLoS Pathog. 2021,17(4):e1009561.
•Imai M, Watanabe T, Kiso M, et al. A highly pathogenic avian H7N9 influenza virus isolated from a human is lethal in some ferrets infected via respiratory droplets. Cell Host & Microbe. 2017; 22:1–12.
•Ip DK, Liao Q, Wu P, et al. Detection of mild to moderate influenza A/H7N9 infection by China’s national sentinel surveillance system for influenza-like illness: case series. BMJ. 2013;346:f3693.
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•Qi W, Jia W, Liu D, et al. Emergence and Adaptation of a Novel Highly Pathogenic H7N9 Influenza Virus in Birds and Humans from a 2013 Human-Infecting Low-Pathogenic Ancestor. J Virol. 2018;92(2):e00921-17.
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国立感染症研究所が提供する関連資料
•鳥インフルエンザA(H7N9)ウイルス感染症に関する臨床情報のまとめ:臨床像・検査診断・治療・予防投薬 (2013年4月26日)
http://www.nih.go.jp/niid/ja/diseases/a/flua-h7n9/2273-idsc/3492-clin-info.html
•鳥インフルエンザA(H7N9)ウイルス感染症に対する院内感染対策(2013年5月17日)http://www.nih.go.jp/niid/ja/diseases/a/flua-h7n9/2273-idsc/3550-hospital-infection.html
•鳥インフルエンザA(H7N9) 患者搬送における感染対策(2014年7月16日)http://www.nih.go.jp/niid/ja/diseases/a/flua-h7n9/2273-idsc/4859-patient-transport-mersandh7n9.html

作成
感染症危機管理研究センター 竹前喜洋、影山努、太田雅之、齋藤智也
実地疫学研究センター 島田智恵
FETP 23期 大森俊、田畑早季子
インフルエンザ・呼吸器系ウイルスセンター 渡邉真治、長谷川秀樹

 

H7N9ra220422 fig1

図1.鳥インフルエンザA(H7N9)ウイルスのヒトへの感染例 n=1568(2019年4月9日現在, 文献1から引用)

 

H7N9ra220422 fig2

図2.中国本土の鳥と環境における鳥インフルエンザA(H7N9)の検出地域別陽性検体数 2013年2月~2022年2月2日
  (Food and Agriculture Organization of the United Nations, H7N9 situation update, 02 March 2022 https://www.fao.org/ag/againfo/programmes/en/empres/H7N9/Situation_update.html

 

Copyright 1998 National Institute of Infectious Diseases, Japan