A(H5N1) Avian Influenza Virus: A New Pandemic Threat on the Horizon?

From Top Italian Scientists Journal
June 2, 2024
A(H5N1) Avian Influenza Virus: A New Pandemic Threat on the Horizon?
Giovanni Di Guardo
A(H5N1) avian influenza virus; viral neurotropism; viral neuropathogenicity; zoonoses; zoonotic pathogens; interhuman transmission; pandemic potential; One Health.
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Giovanni Di Guardo(a)

(a) Retired Professor of General Pathology and Veterinary Pathophysiology at the Veterinary Medical Faculty of the University of Teramo, Localita' Piano d'Accio, 64100 Teramo, Italy.

Correspondence to: gdiguardo@unite.it


The present Editorial deals with the highly pathogenic avian influenza (HPAI) virus A(H5N1), whose clade has been identified in several domestic and wild bird and mammalian species, both terrestrial and aquatic, with mass mortality outbreaks also affecting South American sea lions. Within this fast evolving scenario, the progressively and consistently expanding range of virus-susceptible host species alongside the prominent viral neurotropism and neuropathogenicity are a matter of concern, with A(H5N1) virus having additionally spread among USA cattle, which may also shed it through their milk. Although it is not happening at the moment, the possibility A(H5N1) virus may sooner or later become easily transmissible between people appears to be largely plausible. A collaborative, intersectorial and multidisciplinary approach, based upon the "One Health" concept/principle is strongly needed in order to properly counteract the global menace brought about by the HPAI A(H5N1) virus, thereby taking inspiration from the lessons learned during the COVID-19 pandemic.


Conflict of Interest

The Author declares that there is no conflict of interest.


  1. Di Guardo, G., Roperto S. (2024). AH5N1 avian influenza, a new pandemic behind the corner? (Rapid Response). BMJ https://www.bmj.com/content/380/bmj.p510/rr.
  2. Ariyama, N., et al. (2023). Highly Pathogenic Avian Influenza A(H5N1) Clade Virus in Wild Birds, Chile. Emerg. Infect Dis. 29:1842-1845. doi: 10.3201/eid2909.230067.
  3. Puryear, W., et al. (2023). Highly Pathogenic Avian Influenza A(H5N1) Virus Outbreak in New England Seals, United States. Emerg. Infect. Dis. 29:786-791. doi: 10.3201/eid2904.221538.
  4. Gamarra-Toledo, V., et al. (2023). Mass Mortality of Sea Lions Caused by Highly Pathogenic Avian Influenza A(H5N1) Virus. Emerg. Infect. Dis. 29:2553-2556. doi: 10.3201/eid2912.230192.
  5. Thorsson, E., et al. (2023). Highly Pathogenic Avian Influenza A(H5N1) Virus in a Harbor Porpoise, Sweden. Emerg. Infect. Dis. 29:852-855. doi: 10.3201/eid2904.221426.
  6. Murawski, A., et al. (2024). Highly pathogenic avian influenza A(H5N1) virus in a common bottlenose dolphin (Tursiops truncatus) in Florida. Commun. Biol. 7:476. doi: 10.1038/s42003-024-06.
  7. Reardon, S. (2024). Bird flu in US cows: Where will it end? Nature https://www.nature.com/articles/d41586-024-01333-9.
  8. Gerhard, D. (2024). Deciphering the unusual pattern of bird flu symptoms in cows. The Scientist Magazine. https://www.the-scientist.com/deciphering-the-unusual-pattern-of-bird-fl....
  9. Kristensen, C., et al. (2024). The avian and human influenza A virus receptors sialic acid (SA)-α2,3 and SA-α2,6 are widely expressed in the bovine mammary gland. bioRxiv 2024. 05.03.592326.
  10. Uyeki, T.M., et al. (2024). Highly pathogenic avian influenza A(H5N1) virus infection in a dairy farm worker. N. Engl. J. Med. doi: 10.1056/NEJMc2405371.