Infectious Diseases 2024

Infectious Diseases 2024

Bovine H5N1 influenza transmissible and lethal in animal models

Gu, C., Maemura, T., Guan, L. et al. (2024) Nature 28 October, 2024

A new study published in Nature investigates the transmissibility and pathogenicity of the human isolate huTX37-H5N1, derived from a bovine H5N1 outbreak, using ferrets as a model. The research reveals significant insights into the behavior of this virus and its implications for public health. The huTX37-H5N1 isolate is capable of respiratory droplet transmission in ferrets, indicating that it can spread efficiently among mammals. This transmissibility occurs regardless of the viral load used for infection, suggesting that the virus can reach sufficient levels for transmission even at lower doses. The virus is highly lethal in ferrets and mice, with infected animals exhibiting severe disease characterized by systemic virus spread. However, the human infected with huTX37-H5N1 did not show the severe symptoms typically associated with highly pathogenic avian influenza (HPAI) infections. The study compares huTX37-H5N1 with other H5N1 isolates, noting that it transmits more efficiently than some dairy cattle H5N1 strains. The presence of specific mutations, such as PB2-627K, is suggested to play a role in the virus's pathogenicity.
The researchers concluded that the huTX37-H5N1 isolate poses a significant risk for respiratory droplet transmission among mammals, with potential implications for human health. Despite its lethality in animal models, the virus may not cause severe symptoms in humans, complicating detection and response efforts.