Evidence collection30 April 2024

Influenza H5N1 in mammals

Evidence-based veterinary medicineSmall animalsEquineExoticsFarm animalsMedicine

Introduction

Recent cases of Highly Pathogenic Influenza H5N1, in dairy cattle in the United States, have raised concerns about whether this strain of influenza, which is currently circulating widely in birds, is becoming adapted to mammalian species, and poses a potential threat to human health.

The purpose of this evidence collection is to bring together current reports and evidence regarding cases of Influenza H5N1 in mammals. It does not include papers relating to the situation in birds but does include links to other agencies which report and provide advice on Avian Influenza.

The focus is on Influenza H5N1, as this is the strain of current concern. As this is a rapidly evolving area we include news reports, from reputable sources, and pre-prints, but these will be replaced with peer reviewed articles as soon as these become available.

Overview

Risk to mammals

Lin, T-H. et al (2024) A single mutation in bovine influenza H5N1 hemagglutinin switches specificity to human receptors. Science, 386 (6726), pp. 128-1134. https://doi.org/10.1126/science.adt0180
Gu, C. et al. (2024) A human isolate of bovine H5N1 is transmissible and lethal in animal models. Nature, 636, pp. 711-718. https://doi.org/10.1038/s41586-024-08254-7
Sacristán, C. et al. (2024) Novel Epidemiologic Features of High Pathogenicity Avian Influenza Virus A H5N1 2.3.3.4b Panzootic: A Review. Transboundary and Emerging Diseases, 5322378. https://doi.org/10.1155/2024/5322378
Alberts, F. et al. (2024) Predicting host species susceptibility to influenza viruses and coronaviruses using genome data and machine learning: a scoping review. Frontiers in Veterinary Science. https://doi.org/10.3389/fvets.2024.1358028
Ahrens, A.K. et al. (2024) Novel genotypes of highly pathogenica avian influenza H5N1 clade 2.3.4.4b viruses, Germany, November 2023. Emerging Infectious Disease, 30 (8), pp. 1737-1739. https://doi.org/10.3201/eid3008.240103
Eisfeld, A.J. et al. (2024) Pathogenicity and transmissibility of bovine H5N1 influenza virus. Nature. https://doi.org/10.1038/s41586-024-07766-6
Caserta, L.C. et al. (2024) Spillover of highly pathogenic avian influenza H5N1 virus to dairy cattle. Nature. https://doi.org/10.1038/s41586-024-07849-4
Puryear, W.B. and Runstadler, J.A. (2024) High-pathogenicity avian influenza in wildlife: a changing disease dynamic that is expanding in wild birds and having an increasing impact on a growing number of mammals. Journal of the American Veterinary Medical Association, 262 (5), pp. 601-609. https://doi.org/10.2460/javma.24.01.0053
Runstadler, J.A. and Puryear, W.B. (2024) The virus is out of the barn: the emergence of HPAI as a pathogen of avian and mammalian wildlife around the globe. American Journal of Veterinary Research. https://doi.org/10.2460/ajvr.24.01.0018
Plaza, P.I. et al. (2024) Recent changes in patterns of mammal infection with highly pathogenic avian influenza A (H5N1) virus worldwide. Emerging Infectious Diseases, 30 (3), pp. 444-452. https://doi.org/10.3201%2Feid3003.231098
Elsmo, E.J. et al. (2023) Highly pathogenic avian influenza A (H5N1) virus clade 2.3.4.4b infections in wild terrestrial mammals, United States, 2022. Emerging Infectious Diseases, 29 (12), pp. 2451-2460. https://doi.org/10.3201%2Feid2912.230464
Gilbertson, B. and Subbarao, K. (2023) Mammalian infections with highly pathogenic avian influenza viruses renew concerns of pandemic potential. Journal of Experimental Medicine, 220 (8), no. e20230447. https://doi.org/10.1084/jem.20230447

Risk to humans

Lowen, A.C. et al (2025) Controlling bird flu is urgent—for dairy, wildlife, poultry, pets, and people. Journal of the American Veterinary Medical Association. https://doi.org/10.2460/javma.25.05.0294
Kaiser, F. et al. (2025) Highly pathogenic avian influenza A(H5N1) virus stability in irradiated raw milk and wastewater and on surfaces, United States. Emerging Infectious Diseases, 31 (4), pp. 833–837. https://doi.org/10.3201/eid3104.241615
Avian flu is evolving but what risk does it pose to us? (2024) [BBC Radio 4: The Briefing Room] [Podcast]. Available from: https://www.bbc.co.uk/programmes/m001z6q3 [Accessed 6 June 2024]
Xie, R. et al. (2023) The episodic resurgence of highly pathogenic avian influenza H5 virus. Nature, 622 (7984), pp. 810-817. https://doi.org/10.1038/s41586-023-06631-2
Limb, M. (2023) Fears for human cases of avian influenza. Veterinary Record, 193 (30), pp. 93. https://doi.org/10.1002/vetr.3316
European Food Safety Authority (EFSA) et al. (2024) Drivers for a pandemic due to avian influenza and options for One Health mitigation measures. EFSA Journal, 22 (4), no. e8735. https://doi.org/10.2903/j.efsa.2024.8735
Human case of avian flu detected in England. UKHSA confirms rare case of bird flu A(H5N1) in the West Midlands region [UK Health Security Agency] [online]. Available from: https://www.gov.uk/government/news/human-case-of-avian-flu-detected-in-england [Accessed 18 February 2025]
Hosseini, P. et al. (2025) Qualitative studies on farm managers perception of risk from HPAIV and implementation of biosecurity measures on UK poultry farms. Preventive Veterinary Medicine, 239, 106445. https://doi.org/10.1016/j.prevetmed.2025.106445
Notes from the field: Seroprevalence of highly pathogenic Avian Influenza A(H5) virus infections among bovine veterinary practitioners — United States, September 2024. Morbidity and Mortality Weekly Report, 74 (4), pp. 50-52. Available from: https://www.cdc.gov/mmwr/volumes/74/wr/mm7404a2.htm [Accessed 3 April 2025]

Sources of information on disease outbreaks in animals

United Kingdom

Influenza A (H5N1) infection in mammals: suspect case definition and diagnostic testing criteria [Department for Environment, Food & Rural Affairs and Animal and Plant Health Agency] [online]. Available from: https://www.gov.uk/government/publications/influenza-a-h5n1-of-avian-origin-in-domestic-livestock-in-the-usa [Accessed 3 April 2025]
Housing measures introduced in parts of Yorkshire and the East to protect poultry and other captive birds [Department for Environment, Food & Rural Affairs] [online]. Available from: https://www.gov.uk/government/news/housing-measures-introduced-in-the-north-east-and-east-to-protect-poultry-and-other-captive-birds [Accessed 24 January 2025]
Bird flu (avian influenza): latest situation in England [Department for Environment, Food & Rural Affairs and Animal and Plant Health Agency] [online]. Available from: https://www.gov.uk/government/news/bird-flu-avian-influenza-latest-situation-in-england [Accessed 3 April 2025]
BVA, BVZS, BVPA and BSAVA Avian influenza (AI) advice for vets dealing with wild birds and backyard poultry [BVA] [Online]. Available from: https://www.bva.co.uk/media/5909/ai-guidance-for-vets-july-2024.pdf [Accessed 13 August 2024]

United States

Highly Pathogenic Avian Influenza (Bird Flu) Resource Center. [Cornell University College of Veterinary Medicine] [online]. Available from: https://www.vet.cornell.edu/highly-pathogenic-avian-influenza-bird-flu-resource-center [Accessed 28 October 2025]
Lombard, J. et al. (2025) Invited review: The One Health challenges and opportunities of the H5N1 outbreak in dairy cattle in the United States. Journal of Dairy Science, 108 (7), pp. 6513-6537. https://doi.org/10.3168/jds.2024-26222
Brock, N. et al. (2025) Avian influenza A(H5N1) isolated from dairy farm worker, Michigan, USA. Emerging Infectious Diseases, 31 (6), pp. 1253-1256. https://doi.org/10.3201/eid3106.250386
Influenza A (H5N1) of avian origin in domestic livestock in the USA [Department for Environment, Food & Rural Affairs and Animal and Plant Health Agency] [online]. Available from: https://www.gov.uk/government/publications/influenza-a-h5n1-of-avian-origin-in-domestic-livestock-in-the-usa [Accessed 3 April 2025]
Detections of highly pathogenic avian influenza in mammals [Animal and Plant Health Inspection Service: U.S. Department of Agriculture] [online]. Available from: https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/mammals [Accessed 3 April 2025]
HPAI confirmed cases in livestock [Animal and Plant Health Inspection Service: U.S. Department of Agriculture] [online]. Available from: https://www.aphis.usda.gov/livestock-poultry-disease/avian/avian-influenza/hpai-detections/hpai-confirmed-cases-livestock [Accessed 3 April 2025]
Avian influenza in pets and backyard flocks [American Veterinary Medical Association] [online]. Available from: https://www.avma.org/resources-tools/animal-health-and-welfare/animal-health/avian-influenza/avian-influenza-companion-animals [Accessed 24 January 2025]
Detection of highly pathogenic Avian Influenza (H5N1) in dairy herds: Frequently asked questions [Animal and Plant Health Inspection Service: U.S. Department of Agriculture] [online]. Available from: https://www.aphis.usda.gov/sites/default/files/hpai-dairy-faqs.pdf [Accessed 3 April 2025]

World

Global strategy for the prevention and control of high pathogenicity Avian Influenza (2024–2033) [World Organisation for Animal Health] [online]. Available from: https://www.woah.org/en/document/global-strategy-for-the-prevention-and-control-of-high-pathogenicity-avian-influenza-2024-2033/ [Accessed 3 April 2025]
High pathogenicity avian influenza (HPAI) in cattle [World Organisation for Animal Health] [online]. Available from: https://www.woah.org/en/high-pathogenicity-avian-influenza-hpai-in-cattle/ [Accessed 24 January 2025]
WAHIS: World Animal Health Information System [WAHIS] [online]. Available from: https://wahis.woah.org/#/home [Accessed 3 April 2025]
Influenza: A(H5N1) [World Health Organization] [online]. Available from: https://www.who.int/news-room/questions-and-answers/item/influenza-h5n1 [Accessed 3 April 2025]
European Food Safety Authority et al. (2024) Avian influenza overview March-June 2024. EFSA Journal, 22 (7), no. e8930. https://doi.org/10.2903/j.efsa.2024.8930

Guidance for handling animals

Lyons, K. et al. (2025) Assessing stakeholder inclusion within high pathogenicity avian influenza risk governance strategies in the United Kingdom and United States. Frontiers in Veterinary Science, 12. https://doi.org/10.3389/fvets.2025.1547628
Public health resources for veterinarians and veterinary staff handling animals with HPAI A (H5N1) virus infection on dairy farms [U.S. Centers for Disease Control and Prevention] [online]. Available from: https://www.cdc.gov/bird-flu/hcp/animals/resources-veterinarians-dairy.html [Accessed 4 November 2024]
Interim guidance for employers to reduce exposure to novel influenza A (such as H5N1 bird flu) for people working with or exposed to animals [U.S. Centers for Disease Control and Prevention] [online]. Available from: https://www.cdc.gov/bird-flu/prevention/worker-protection-ppe.html? [Accessed 4 November 2024]
Highly pathogenic avian influenza A (H5N1): Guidance for veterinarians assessing HPAI H5N1 in domestic felines [Colorado Department of Public Health & Environment] [online]. Available from: Guidance for Veterinarians assessing H5N1 HPAI in domestic felines [Accessed 4 November 2024]
Considerations for veterinarians: Evaluating and handling of cats potentially exposed to highly pathogenic avian influenza A (H5N1) virus [U.S. Centers for Disease Control and Prevention] [online]. Available from: https://www.cdc.gov/bird-flu/hcp/animals/index.html?CDC_AA_refVal=https%3A%2F%2Fwww.cdc.gov%2Fflu%2Favianflu%2Fveterinarians-handling-cats.htm [Accessed 4 November 2024]
FDA outlines ways to reduce risk of HPAI in cats. [US Food and Drug Administration] [online] Available form: https://www.fda.gov/animal-veterinary/cvm-updates/fda-outlines-ways-reduce-risk-hpai-cats?utm_medium=email&utm_source=govdelivery [Accessed 24 January 2025]

Reports and information on Influenza H5N1 in mammals

Cats

Bonilla-Aldana, K. et. al. (2025) Highly pathogenic avian influenza H5N1 in cats (Felis catus): a systematic review and meta-analysis. Animals, 15 (10), no. 1441. https://doi.org/10.3390/ani15101441
Joint press release by the FASFC, Sciensano and the FPS Public Health, Food Chain Safety and Environment: Avian influenza detected in two cats of a poultry keeper in Saint-Gilles-Waes [Federal Agency for the Safety of the Food Chain] [online]. Available from: https://favv-afsca.be/fr/publication/communique-de-presse-conjoint-de-lafsca-sciensano-et-du-spf-sante-publique-securite-de-la-chaine [Accessed 3 April 2025]
Highly pathogenic Avian Influenza A(H5N1) virus infection of indoor domestic cats within dairy industry worker households — Michigan, May 2024. Morbidity and Mortality Weekly Report, 74 (5), pp. 61–65. Available from: https://www.cdc.gov/mmwr/volumes/74/wr/mm7405a2.htm [Accessed 3 April 2025]
Kang, Y.M. et al. (2024) Highly pathogenic avian influenza A(H5N1) virus infection in cats, South Korea, 2023. Emerging Infectious Diseases, 30 (12), pp. 2510-2520. https://doi.org/10.3201/eid3012.240154
Influenza A (highly pathogenic avian influenza H5N1) in domestic cats [Colorado Veterinary Medical Association] [online]. Available from: https://www.colovma.org/cvma-news/influenza-a-highly-pathogenic-avian-influenza-h5n1-in-domestic-cats/ [Accessed 19 September 2024]
Weese, S. (2024) H5N1 influenza in cats in Colorado [Worms & Germs Blog] [online]. Available from: https://www.wormsandgermsblog.com/2024/08/articles/animals/cats/h5n1-influenza-in-cats-in-colorado/ [Accessed 19 September 2024]
Frymus, T. et al. (2021) Influenza virus infections in cats. Viruses, 13 (8), no. 1435. https://doi.org/10.3390/v13081435
Mainenti, M. et al. (2024) Distribution of lesions and detection of influenza A(H5N1) virus, clade 2.3.4.4b, in ante- and postmortem samples from naturally infected domestic cats on U.S. dairy farms. Journal of Veterinary Diagnostic Investigation. https://doi.org/10.1177/10406387241300464
Szaluś-Jordanow, O. et al. (2023) A fatal A/H5N1 avian influenza virus infection in a cat in Poland. Microorganisms, 11 (9), no. 2263. https://doi.org/10.3390/microorganisms11092263
Kang, Y-M. et al. (2024) Highly pathogenic avian influenza A(H5N1) virus infection in cats, South Korea, 2023. Emerging Infectious Diseases, 30 (12), pp. 2510-2520. https://doi.org/10.3201/eid3012.240154
Rabalski, L. et al. (2023) Emergence and potential transmission route of avian influenza A (H5N1) virus in domestic cats in Poland, June 2023. Eurosurveillance, 28 (31), no. 2300390. https://doi.org/10.2807/1560-7917.ES.2023.28.31.2300390
Briand, F.X. et al. (2023) Highly pathogenic avian influenza A (H5N1) Clade 2.3. 4.4 b virus in domestic cat, France, 2022. Emerging Infectious Diseases, 29 (8), pp. 1696-1698. https://doi.org/10.3201/eid2908.230188
Villanueva‐Saz, S. et al. (2024) Serological exposure to influenza A in cats from an area with wild birds positive for avian influenza. Zoonoses and Public Health, 71 (3), pp. 324-330. https://doi.org/10.1111/zph.13085
Sillman, S.J. et al. (2023) Naturally occurring highly pathogenic avian influenza virus H5N1 clade 2.3. 4.4 b infection in three domestic cats in North America during 2023. Journal of Comparative Pathology, 205, pp.17-23. https://doi.org/10.1016/j.jcpa.2023.07.001

Cattle

Sanchez-Rojas, I.C. et al. (2025) Highly pathogenic avian influenza (H5N1) clade 2.3.4.4b in cattle: a rising One Health concern. Animals, 15 (13), no. 1963. https://doi.org/10.3390/ani15131963
Stachler, E. et. al. (2025) Establishing methods to monitor influenza (A)H5N1 virus in dairy cattle milk, Massachusetts, USA. Emerging Infectious Diseases, 31 (13), pp. S70–S75. https://doi.org/10.3201/eid3113.250087
Rodriguez, Z. et. al. (2025) Characterization and health, productivity, and economic effects of highly pathogenic avian influenza H5N1 outbreak in dairy cattle. Journal of Dairy Science, 108 (6), pp. 6349-6358. https://doi.org/10.3168/jds.2025-26377
Peña-Mosca, F. et al. (2025) The impact of influenza A H5N1 virus infection in dairy cows. Research Square. https://doi.org/10.21203/rs.3.rs-6101018/v1
Highly pathogenic avian influenza H5N1 genotype B3:13 in dairy cattle: National epidemiologic brief [Animal and Plant Health Inspection Service: U.S. Department of Agriculture] [online]. Available from: https://www.aphis.usda.gov/sites/default/files/hpai-dairy-national-epi-brief.pdf [Accessed 5 November 2024]
Mostafa, A. et al. (2025) Replication kinetics, pathogenicity and virus-induced cellular responses of cattle-origin influenza A(H5N1) isolates from Texas, United States. Emerging Microbes & Infections, 14 (1). https://doi.org/10.1080/22221751.2024.2447614
Baker, A.L. et al. (2024) Experimental reproduction of viral replication and disease in dairy calves and lactating cows inoculated with highly pathogenic avian influenza H5N1 clade 2.3.4.4b. bioRxiv, https://doi.org/10.1101/2024.07.12.603337
Nelli, R.K. et al. (2024) Sialic acid receptor specificity in mammary gland of dairy cattle infected with highly pathogenic avian influenza A (H5N1) virus. Emerging Infectious Diseases, 30 (7), pp. 1361-1373. https://doi.org/10.3201/eid3007.240689
Oguzie, J.U. et al. (2024) Avian influenza A (H5N1) virus among dairy cattle, Texas, USA. Emerging Infectious Diseases, 30 (7), pp. 1425-1429. https://doi.org/10.3201/eid3007.240717
Hu, X. et al. (2024) Highly Pathogenic Avian Influenza A (H5N1) clade 2.3.4.4b Virus detected in dairy cattle. bioRxiv. https://doi.org/10.1101/2024.04.16.588916
Weese, S. (2024) Update: Dairy cattle and H5N1 flu (April 11) [Worms & Germs blog] [online]. Available from: https://www.wormsandgermsblog.com/2024/04/articles/animals/other-animals/h5n1-in-dairy-cattle-april-11-2024-update/ [Accessed 30 April 2024]
High pathogenicity avian influenza in cattle [World Organisation for Animal Health] [online]. Available from: https://www.woah.org/en/high-pathogenicity-avian-influenza-in-cattle/ [Accessed 23 April 2024]
USDA, FDA and CDC share update on HPAI detections in dairy cattle [Animal and Plant Health Inspection Service: US Department of Agriculture] [online]. Available from: https://www.aphis.usda.gov/news/agency-announcements/usda-fda-cdc-share-update-hpai-detections-dairy-cattle [Accessed 23 April 2024]
News and updates: USDA Actions to Protect Livestock Health From Highly Pathogenic H5N1 Avian Influenza
[Animal and Plant Health Inspection Service: US Department of Agriculture] [online]. Available from: https://www.aphis.usda.gov/news/agency-announcements/usda-actions-protect-livestock-health-highly-pathogenic-h5n1-avian [Accessed 23 April 2023]
Kozlov, M. and Mallapaty, S. (2024) Bird flu outbreak in US cows: why scientists are concerned. Nature, 628, pp. 484-485 https://doi.org/10.1038/d41586-024-01036-1
Sreenivasan, C.C. et al. (2019) Influenza A in bovine species: a narrative literature review. Viruses, 11 (6), no. 561. https://doi.org/10.3390/v11060561

Companion animals

Sykes, J.E. (2025) Companion animals and H5N1 highly pathogenic avian influenza: cause for concern? Journal of the American Veterinary Medical Association, 263 (11), pp. 1355-1363. https://doi.org/10.2460/javma.25.06.0388
Ly, H. (2024) Highly pathogenic avian influenza H5N1 virus infection of companion animals. Virulence, 15 (1), no. 2289780. https://doi.org/10.1080/21505594.2023.2289780

Dogs

Brown, J.D. et al. (2024) Antibodies to influenza A(H5N1) virus in hunting dogs retrieving wild fowl, Washington, USA. Emerging Infectious Diseases, 30 (6), pp. 1271-1274. https://doi.org/10.3201/eid3006.231459
Szaluś-Jordanow, O. et al. (2024) Upper respiratory tract disease in a dog infected by a highly pathogenic avian A/H5N1 virus. Microorganisms, 12 (4), no. 689. https://doi.org/10.3390/microorganisms12040689

Horses

Newton, J.R. et al. (2025) Comments on ‘Should the equine community be concerned about the emergence of the H5N1 subtype of highly pathogenic avian influenza in US cattle?’ Equine Veterinary Journal, 57 (2), pp. 532-534. https://doi.org/10.1111/evj.14460
Murcia, P.R. et al. (2025) Should the equine community be concerned about the emergence of the H5N1 subtype of highly pathogenic avian influenza in US cattle? Equine Veterinary Journal, 57 (2), pp. 530-531. https://doi.org/10.1111/evj.14439
Damdinjav, B. et al. (2025) Evidence of Influenza A(H5N1) spillover infections in horses, Mongolia. Emerging Infectious Diseases, 31 (1), pp. 183-185. https://doi.org/10.3201/eid3101.241266.

Marine mammals

Haman, K.H. et al. (2024) A comprehensive epidemiological approach documenting an outbreak of H5N1 highly pathogenic avian influenza virus clade 2.3.4.4b among gulls, terns, and harbor seals in the Northeastern Pacific. Frontiers in Veterinary Science, 11. https://doi.org/10.3389/fvets.2024.1483922
de Carvalho Araujo, A. et al. (2024) Mortality in sea lions is associated with the introduction of the H5N1 clade 2.3.4.4b virus in Brazil October 2023: whole genome sequencing and phylogenetic analysis. BMC Veterinary Research, 20, no. 285. https://doi.org/10.1186/s12917-024-04137-1
Puryear, W. (2023) Highly pathogenic avian influenza A (H5N1) virus outbreak in New England seals, United States. Emerging Infectious Diseases, 29 (4), pp. 786-791. https://doi.org/10.3201/eid2904.221538
Thorsson, E. et al. (2023) Highly pathogenic avian influenza A (H5N1) virus in a harbor porpoise, Sweden. Emerging Infectious Diseases, 29 (4), pp.852-855. https://doi.org/10.3201/eid2904.221426
Lair, S. (2023) Outbreak of Highly Pathogenic Avian Influenza Virus H5N1 in Seals in the St. Lawrence Estuary, Quebec, Canada. bioRxiv, 2023.11.16.567398. https://doi.org/10.1101/2023.11.16.567398
Gamarra-Toledo, V. et al. (2023) Mass mortality of sea lions caused by highly pathogenic Avian Influenza A (H5N1) virus. Emerging Infectious Diseases, 29 (12), pp. 2553-2556. https://doi.org/10.3201/eid2912.230192

Multispecies outbreaks

Burrough, E.R. et al. (2024) Highly pathogenic avian influenza A(H5N1) Clade 2.3.4.4b virus infection in domestic dairy cattle and cats, United States, 2024. Emerging Infectious Diseases, 30 (7), pp. 1335-1343. https://doi.org/10.3201/eid3007.240508
Rimondi, A. et al. (2024) Highly pathogenic avian influenza A (H5N1) viruses from multispecies outbreak, Argentina, August 2023. Emerging Infectious Diseases, 30 (4), pp. 812-814. https://doi.org/10.3201%2Feid3004.231725

Mustelids

Kareinen, L. et al. (2024) Highly pathogenic avian influenza A(H5N1) virus infections on fur farms connected to mass mortalities of black-headed gulls, Finland, July to October 2023. Euro Eurosurveillance, 29 (25), 2400063. https://doi.org/10.2807/1560-7917.ES.2024.29.25.2400063
Oguzie, J.U. et al. (2024) Avian influenza A(H5N1) virus among dairy cattle, Texas, USA. Emerging Infectious Diseases, 30 (7), pp. 1425-1429. https://doi.org/10.3201/eid3007.240717
Belser, J.A. et al. (2024) Fatal infection in ferrets after ocular inoculation with highly pathogenic avian influenza A(H5N1) virus. Emerging Infectious Diseases, 30 (7), pp. 1484-1487. https://doi.org/10.3201/eid3007.240520
Agüero, M. et al. (2023) Highly pathogenic avian influenza A (H5N1) virus infection in farmed minks, Spain, October 2022. Eurosurveillance, 28 (3), no. 2300001. https://doi.org/10.2807/1560-7917.ES.2023.28.3.2300001
Pulit-Penaloza, J.A. et al. (2024) Highly pathogenic avian influenza A (H5N1) virus of clade 2.3. 4.4 b isolated from a human case in Chile causes fatal disease and transmits between co-housed ferrets. Emerging Microbes & Infections, no. 2332667. https://doi.org/10.1080/22221751.2024.2332667

Pigs

Mena-Vasquez, J. et al. (2025) Emerging threats of HPAI H5N1 clade 2.3.4.4b in swine: knowledge gaps and the imperative for a One Health approach. Frontiers in Veterinary Science, 12. https://doi.org/10.3389/fvets.2025.1648878
Parys, A. et al. (2023) Surveillance and genomic characterization of influenza A and D viruses in swine, Belgium and the Netherlands, 2019–2021. Emerging Infectious Diseases, 29 (7), pp. 1459-1464. https://doi.org/10.320/eid2907.221499
Mace, J.L. and Knight, A. (2023) Influenza risks arising from mixed intensive pig and poultry farms, with a spotlight on the United Kingdom. Frontiers in Veterinary Science, 10, no. 1310303. https://doi.org/10.3389/fvets.2023.1310303
Graaf, A. et al.(2023) Low susceptibility of pigs against experimental infection with HPAI virus H5N1 clade 2.3. 4.4 b. Emerging Infectious Diseases, 29 (7), pp. 1492-1495. https://doi.org/10.3201/eid2907.230296
Arruda, B. et al. (2024) Divergent pathogenesis and transmission of highly pathogenic avian influenza a (H5N1) in swine. Emerging Infectious Diseases, 30 (4), pp. 738-751. https://doi.org/10.3201/eid3004.231141

Poultry

Drehoff, C.C. et al. (2024) Cluster of influenza A(H5) cases associated with poultry exposure at two facilities — Colorado, July 2024. Morbidity and Mortality Weekly Report, 73 (34), pp. 734-739. http://dx.doi.org/10.15585/mmwr.mm7334a1

Sheep

Influenza of avian origin (H5N1) has been confirmed in a single sheep in Yorkshire [Department for Environment, Food & Rural Affairs and Animal and Plant Health Agency]. Available from: https://www.gov.uk/government/news/influenza-of-avian-origin-confirmed-in-a-sheep-in-yorkshire [Accessed 3 April 2025]

Wildlife

Turner, H.M. et al. (2025) Highly pathogenic avian influenza virus exposure and infection in free-ranging bobcats (Lynx rufus) in New York, USA. Journal of Wildlife Diseases. Available from: https://meridian.allenpress.com/jwd/article/doi/10.7589/JWD-D-24-00137/506133/Highly-Pathogenic-Avian-Influenza-Virus-Exposure [Accessed: 9 May 2025]
Paravinja, N. et al. (2025) Highly pathogenic Avian Influenza virus in mammals: Lack of detection in cattle with respiratory tract infections and genetic analysis of sporadic spillover infections in wild Mammals in Bavaria, Southern Germany, 2022–2023. Zoonoses and Public Health. https://doi.org/10.1111/zph.13217
Guan, L. et al. (2024) Cow’s milk containing avian influenza A (H5N1) virus – Heat inactivation and infectivity in mice. New England Journal of Medicine, 391 (1), pp. 87-90. https://doi.org/10.1056/NEJMc2405495
Vreman, S. et al. (2023) Zoonotic mutation of highly pathogenic avian influenza H5N1 virus identified in the brain of multiple wild carnivore species. Pathogens, 12 (2), no. 168. https://doi.org/10.3390/pathogens12020168
Bordes, L. et al. (2023) Highly pathogenic avian influenza H5N1 virus infections in wild red foxes (Vulpes vulpes) show neurotropism and adaptive virus mutations. Microbiology spectrum, 11 (1), e02867-22. https://doi.org/10.1128/spectrum.02867-22
Rijks, J.M. et al. (2021) Highly pathogenic avian influenza A (H5N1) virus in wild red foxes, the Netherlands, 2021. Emerging infectious diseases, 27 (11), pp. 2960-2962. https://doi.org/10.3201/eid2711.211281
Baechlein, C. et al. (2023) Neurotropic highly pathogenic avian influenza A (H5N1) virus in red foxes, Northern Germany. Emerging Infectious Diseases, 29 (12), pp. 2509-2512. https://doi.org/10.3201/eid2912.230938
Jakobek, B.T. et al. (2023) Influenza A (H5N1) virus infections in 2 free-ranging black bears (Ursus americanus), Quebec, Canada. Emerging Infectious Diseases, 29 (10), pp.2145-2149 https://doi.org/10.3201/eid2910.230548

Immunity / vaccination

Li, Q. et al. (2025) Highly pathogenic avian influenza H5N1 clade 2.3.4.4b hemagglutinin and/or neuraminidase elicit immunity in a recombinant nanoparticle vaccine. Cell Biomaterials, no. 100070. https://doi.org/10.1016/j.celbio.2025.100070
Levine, M.Z. et al. (2025) Neutralizing antibody response to influenza A(H5N1) virus in dairy farm workers, Michigan, USA. Emerging Infectious Diseases, 31 (4), pp. 876–878. https://doi.org/10.3201/eid3104.250007
Sun, X. et al. (2025) Effect of prior Influenza A(H1N1)pdm09 virus infection on pathogenesis and transmission of human Influenza A(H5N1) Clade 2.3.4.4b virus in ferret model. Emerging Infectious Diseases, 31 (3), pp. 458-466. https://doi.org/10.3201/eid3103.241489
Domínguez-Odio, A. et al. (2025) Research publications and global manufacture of veterinary vaccines against avian influenza A (2019-2023). Frontiers in Veterinary Science, 12. https://doi.org/10.3389/fvets.2025.1394675

About evidence collections

Evidence collections bring together collections of published papers on topics of interest and importance to the veterinary professions. Papers are chosen for relevance and accessibility, with the full text of articles either being available through the RCVS Knowledge library, on open access or from other publications to which a significant number of veterinary professionals are likely to have access. This means that there may be relevant evidence that is not included.

If you would like assistance in searching for further evidence on this topic you may find the following helpful EBVM Toolkit 2: Finding the best available evidence.

If you would like to suggest a paper for inclusion in one of our published evidence collections, or a topic for a future collection, please email library@rcvsknowledge.org