Genotype B3.13 influenza A(H5N1) viruses isolated from dairy cattle demonstrate high virulence in laboratory models, but retain avian virus-like properties

• Published in: Nature communications Vol. 16; no. 1; pp. 6771 - 12
• Main Authors: Fabrizio, Thomas P., Kandeil, Ahmed, Harrington, Walter N., Jones, Jeremy C., Jeevan, Trushar, Andreev, Konstantin, Seiler, Patrick, Fogo, Jonathan, Davis, Morgan L., Crumpton, Jeri Carol, Franks, John, DeBeauchamp, Jennifer, Vogel, Peter, Daniels, C. Scanlon, Poulson, Rebecca L., Bowman, Andrew S., Govorkova, Elena A., Webby, Richard J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 23.07.2025; Nature Publishing Group; Nature Portfolio
• Subjects: 13/106; 13/51; 14/63; 45/23; 45/88; 631/326/596/1578; 631/326/596/2555; 631/326/596/2563; 64/60; Animals; Antiviral agents; Antiviral Agents - pharmacology; Avian flu; Birds - virology; Cattle; Cow's milk; Dairy cattle; Disease Models, Animal; Epithelial cells; Epithelium; Fatalities; Female; Ferrets - virology; Genotype; Genotype & phenotype; Genotypes; Glycosylation; Humanities and Social Sciences; Humans; Influenza; Influenza A; Influenza A Virus, H5N1 Subtype - drug effects; Influenza A Virus, H5N1 Subtype - genetics; Influenza A Virus, H5N1 Subtype - isolation & purification; Influenza A Virus, H5N1 Subtype - pathogenicity; Influenza in Birds - virology; Influenza, Human - transmission; Influenza, Human - virology; Laboratory animals; Mice; Milk; Milk - virology; Mortality; multidisciplinary; Mustela; Orthomyxoviridae Infections - transmission; Orthomyxoviridae Infections - virology; Pathogenesis; Poultry; Preferences; Science; Science (multidisciplinary); Vaccines; Vigilance; Virulence; Virulence - genetics; Virus Replication; Viruses; Zoonoses; Louisiana; Ghana; Ohio; California; United States > US; Texas
• DOI: 10.1038/s41467-025-61757-3
• ISSN: 2041-1723

In March 2024, clade 2.3.4.4b highly pathogenic avian influenza A(H5N1) viruses were first detected in U.S. dairy cattle. Similar viruses have since caused 70 zoonotic human infections. To assess changes to zoonotic potential, we characterized A(H5N1) clade 2.3.4.4b viruses isolated from cows’ milk and birds. Bovine-derived viruses are lethal in mice and ferrets and transmit to direct but not airborne contact ferrets. All viruses replicate in human bronchial epithelial cells despite preferentially binding avian virus-like receptors. The bovine-derived viruses remain susceptible to FDA-approved antivirals, and they are inhibited by sera from ferrets vaccinated with WHO-recommended candidate vaccine viruses (CVV) or human sera from clade 2.3.4.4c vaccinees. While 2.3.4.4b viruses induce severe disease in mammalian models, they retain many avian virus-like characteristics. Combined, we conclude that the risk of contemporary bovine-derived viruses to humans not in contact with affected animals is low. However, heightened vigilance remains essential to promptly detect and respond to any changes. Bovine H5N1 viruses are lethal in laboratory animals, but they retain avian traits including limited transmission. Their responsiveness to approved antivirals and candidate vaccines lowers human risk, but ongoing surveillance is critically needed.