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EFSA J. 2023 Jun; 21(6): e08039.
Published online 2023 Jun 7. doi: 10.2903/j.efsa.2023.8039
PMCID: PMC10245295
PMID: 37293570

Avian influenza overview March – April 2023

European Food Safety Authority, European Centre for Disease Prevention and Control, European Union Reference Laboratory for Avian Influenza,corresponding author Cornelia Adlhoch, Alice Fusaro, José L Gonzales, Thijs Kuiken, Grazina Mirinaviciute, Éric Niqueux, Karl Stahl, Christoph Staubach, Calogero Terregino, Alessandro Broglia, Lisa Kohnle, and Francesca Baldinelli
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Abstract

Between 2 March and 28 April 2023, highly pathogenic avian influenza (HPAI) A(H5Nx) virus, clade 2.3.4.4b, outbreaks were reported in domestic (106) and wild (610) birds across 24 countries in Europe. Poultry outbreaks occurred less frequently compared to the previous reporting period and compared to spring 2022. Most of these outbreaks were classified as primary outbreaks without secondary spread and some of them associated with atypical disease presentation, in particular low mortality. In wild birds, black‐headed gulls continued to be heavily affected, while also other threatened wild bird species, such as the peregrine falcon, showed increased mortality. The ongoing epidemic in black‐headed gulls, many of which breed inland, may increase the risk for poultry, especially in July–August, when first‐year birds disperse from the breeding colonies. HPAI A(H5N1) virus also continued to expand in the Americas, including in mammalian species, and is expected to reach the Antarctic in the near future. HPAI virus infections were detected in six mammal species, particularly in marine mammals and mustelids, for the first time, while the viruses currently circulating in Europe retain a preferential binding for avian‐like receptors. Since 13 March 2022 and as of 10 May 2023, two A(H5N1) clade 2.3.4.4b virus detections in humans were reported from China (1), and Chile (1), as well as three A(H9N2) and one A(H3N8) human infections in China. The risk of infection with currently circulating avian H5 influenza viruses of clade 2.3.4.4b in Europe remains low for the general population in the EU/EEA, and low to moderate for occupationally or otherwise exposed people.

Keywords: avian influenza, captive birds, HPAI, humans, monitoring, poultry, wild birds.

Notes

Suggested citation: EFSA (European Food Safety Authority), ECDC (European Centre for Disease Prevention and Control), EURL (European Reference Laboratory for Avian Influenza) , Adlhoch C, Fusaro A, Gonzales JL, Kuiken T, Mirinaviciute G, Niqueux É, Stahl K, Staubach C, Terregino C, Broglia A, Kohnle L and Baldinelli F, 2023. Scientific report: Avian influenza overview March–April 2023. EFSA Journal 2023;21(6):8039, 45 pp. 10.2903/j.efsa.2023.8039 [PMC free article] [PubMed] [CrossRef] [Google Scholar]

Requestor: European Commission

Question number: EFSA‐Q‐2023‐00093 and Commission request 280 to ECDC (SANTE.B.2/IK/mo (2023)2182203).

Acknowledgements: In addition to the listed authors, EFSA, ECDC and the EURL wish to thank the Member State representatives who provided epidemiological data on avian influenza outbreaks or shared sequence data: Andrea Höflechner, Sandra Revilla‐Fernández and Irene Zimpernik (Austria), Ingeborg Mertens, Mieke Steensels and Steven Van Borm (Belgium), Aleksandra Miteva (Bulgaria), Vasiliki Christodoulou, Savvas Savva, and Giorgos Krasias (Cyprus), Alexander Nagy and Lucie Kalášková (Czechia), Savić Vladimir (Croatia), Charlotte Kristiane Hjulsager and Michelle Fischer Carlsen (Denmark), Imbi Nurmoja, Kärt Jaarma (Estonia), Célia Locquet, Béatrice Grasland, Audrey Schmitz and François‐Xavier Briand (France), Anne Pohlmann and Timm Harder (Germany), Georgina Helyes (Hungary), Paolo Mulatti, Francesca Scolamacchia, Isabella Monne, Bianca Zecchin, Ambra Pastori, Diletta Fornasiero, Luca Martelli and Francesco Bonfante (Italy), Audrey Jenkinson and Laura Garza Cuartero (Ireland), Chantal Snoeck (Luxembourg), Vitalie Caraus and Popa Oxana (Moldova), Britt Gjerset (Norway), Aleksandra Podrażka, Krzysztof Śmietanka and Edyta Swieton (Poland), Iuliana Onita and Flavius Prelipcean (Romania), Marcel Spierenburg and Nancy Beerens (the Netherlands), Martin Chudy, Barbora Pavlikova, Martin Tinak and Zuzana Dirbakova (Slovakia), Brigita Slavek, Aleksandra Hari, Jedrt Maurer Wernig, Tina Arič and Breda Hrovatin (Slovenia), Elena García Villacieros, Luis José Romero Gonzalez, Germán Cáceres Garrido, Monserrat Agüero García and Azucena Sánchez (Spain), Malin Grant and Siamak Zohari (Sweden), Dominique Suter and Claudia Bachofen (Switzerland); Ron Fouchier from Erasmus Medical Center (The Netherlands); Ian Brown from the Animal and Plant Health Agency (United Kingdom); Camille Delavenne from AUSVET Europe for conducting the data analysis under the contract OC/EFSA/ALPHA/2021/02; Linnea Lindgren Kero for the support provided under the contract OC/EFSA/DATA/2021/01; Barbara Lanfranchi from RANDSTAD for the support provided; the authors, originating and submitting laboratories of the sequences from GISAID's EpiFlu™ Database, which is used for this assessment (Annex D); Edoardo Colzani from ECDC as well as Inma Aznar and Gina Cioacata from EFSA for the support provided to this scientific output.

Approved: 10 May 2023

Note: This article was originally published on the EFSA website www.efsa.europa.eu on and ECDC website www.ecdc.europa.eu on 12 May 2023 as part of EFSA's urgent publication procedures. Sections 2.3.1, 2.3.3, 2.6 and 3 were updated on 5 June on the EFSA and ECDC websites. The article was published on the Wiley Online Library on 7 June 2023.

References

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