Characterization of a Highly Pathogenic H5N1 Avian Influenza Virus Isolated from Infected Cows and Its Potential for Mammalian Transmission

Centrala begrepp

A highly pathogenic H5N1 avian influenza virus isolated from infected cow milk in the US exhibited systemic spread and tropism in mice and ferrets, as well as the ability to bind to human upper airway receptors, suggesting potential for increased mammalian infection and transmission.

Sammanfattning

The content describes the characterization of a highly pathogenic H5N1 avian influenza (HPAI H5N1) virus isolated from infected cow milk during an unprecedented outbreak in the US in 2024. The virus was found to spread systemically, including to the mammary glands, in both mice and ferrets, similar to an older HPAI H5N1 virus isolate. Importantly, the bovine HPAI H5N1 virus was also able to bind to sialic acids expressed in human upper airways, and it exhibited inefficient transmission to exposed ferrets, with one out of four ferrets seroconverting without detectable virus. These findings suggest that the bovine HPAI H5N1 virus possesses features that may facilitate increased infection and transmission in mammals, posing a potential public health risk.

Statistik

One out of four exposed ferrets seroconverted without virus detection.

Citat

"Bovine HPAI H5N1 virus thus possesses features that may facilitate infection and transmission in mammals."

Viktiga insikter från

Pathogenicity and transmissibility of bovine H5N1 influenza virus - Nature

by Amie J. Eisf... på www.nature.com 07-08-2024

https://www.nature.com/articles/s41586-024-07766-6

Djupare frågor

What other genetic or molecular factors might contribute to the increased pathogenicity and transmissibility of the bovine HPAI H5N1 virus compared to previous HPAI H5N1 strains?

The increased pathogenicity and transmissibility of the bovine HPAI H5N1 virus compared to previous strains could be attributed to several genetic or molecular factors. One key factor could be mutations in the hemagglutinin (HA) protein, which plays a crucial role in viral attachment and entry into host cells. Changes in the HA protein may enhance the virus's ability to bind to host cell receptors, facilitating infection and transmission. Additionally, mutations in the polymerase genes of the virus could lead to increased replication efficiency, allowing for higher viral loads and potentially more severe disease outcomes. Furthermore, alterations in other viral proteins, such as neuraminidase (NA) or nucleoprotein (NP), could also contribute to the enhanced pathogenicity and transmissibility of the bovine HPAI H5N1 virus.

How might the potential for human-to-human transmission of the bovine HPAI H5N1 virus be further evaluated, and what public health measures could be implemented to mitigate the risk of a pandemic?

To evaluate the potential for human-to-human transmission of the bovine HPAI H5N1 virus, further studies could be conducted using animal models, such as ferrets, to assess the virus's ability to spread between individuals. Additionally, epidemiological investigations in areas where human cases have been reported could help determine if there is evidence of sustained human-to-human transmission. Public health measures to mitigate the risk of a pandemic could include enhanced surveillance and monitoring of human and animal populations for HPAI H5N1 infections, rapid identification and isolation of cases, development of vaccines targeting the bovine HPAI H5N1 virus, and implementation of strict biosecurity measures in agricultural settings to prevent further spread of the virus.

Given the ability of the bovine HPAI H5N1 virus to infect multiple species, including cows, poultry, and cats, what broader implications does this have for the emergence and spread of zoonotic influenza viruses with pandemic potential?

The ability of the bovine HPAI H5N1 virus to infect multiple species raises concerns about the potential for zoonotic transmission and the emergence of novel influenza strains with pandemic potential. Cross-species transmission events, such as those observed in bovines, poultry, and cats, highlight the interconnectedness of human, animal, and environmental health. The spread of zoonotic influenza viruses underscores the importance of One Health approaches that integrate human, animal, and environmental health surveillance and response efforts. By understanding the factors driving the emergence and spread of zoonotic influenza viruses, public health authorities can better prepare for and mitigate the risks of future pandemics.