In a groundbreaking study published in the journal Cell, researchers have unveiled alarming details about the airborne transmission of the avian H3N8 influenza virus, a strain previously isolated from humans. The study, led by Honglei Sun and a team of experts, reveals the virus’s potential to cause a pandemic, highlighting its high virulence in mammalian hosts and efficient replication in human respiratory epithelial cells.
In recent years, the H3N8 avian influenza viruses have caused confirmed human infections in China, with a fatal case reported in 2023. These viruses are prevalent in chicken flocks, but their zoonotic characteristics are not well understood. The recent study, however, paints a concerning picture, demonstrating that human isolates of the H3N8 virus can cause severe pathology in mice and ferrets, indicating a high potential for human transmission.
The research, conducted by institutions including the National Key Laboratory of Veterinary Public Health and Safety and the Chinese National Influenza Center, reveals that the virus isolated from a patient with severe pneumonia was capable of transmission between ferrets through respiratory droplets. This finding underscores the urgent need for further research and preparedness to prevent potential outbreaks.
Key Findings from the Study
- Efficient Replication in Human Cells: The human-derived H3N8 viruses were found to replicate efficiently in human respiratory epithelial cells, with a significantly higher number of infected cells compared to chicken-derived H3N8 viruses.
- High Virulence in Mammalian Hosts: The study revealed that the human isolates of the H3N8 virus were highly virulent in mice and ferrets, causing severe pathology and displaying higher replication capacity than chicken isolates.
- Potential for Airborne Transmission: One of the human H3N8 isolates demonstrated efficient respiratory droplet transmission in ferrets, a model organism for studying influenza virus transmission in humans. This finding indicates a potential for airborne transmission in humans, raising concerns about the virus’s pandemic potential.
Given the potential public health implications of these findings, it is crucial to ramp up research efforts to understand the zoonotic features of H3N8 viruses better. The study calls for a comprehensive investigation into the virus’s infection performance in human respiratory epithelial cells and mammalian models, as well as an evaluation of host immunity in human populations against H3N8 avian influenza viruses.
For more details on the study, you can access the full article DOI: 10.1016/j.cell.2023.08.011.