Avian Influenza Outbreak in the United States: Current Knowledge and Unknown Aspects

  Highly pathogenic avian influenza is a contagious viral disease that primarily circulates among wild and domestic avian species. However, there are instances where the avian flu virus can cross species barriers, infecting animals such as dairy cattle and occasionally posing a risk to human health.

Pathogenicity refers to the severity of illness in the infected animal. Highly pathogenic avian influenza, the variant responsible for the ongoing outbreak, can spread from the respiratory system to other organs, frequently leading to fatal outcomes in birds within a span of 48 hours. In the past ten years, instances of avian influenza affecting mammals have shown an upward trend.

According to Abraham, mammal infection typically occurs when the animal consumes a bird that is carrying the infection. By 2024, initial notifications emerged concerning the transmission of avian influenza (H5N1 strain) among domesticated cattle in the United States, likely through cow-to-cow contact. Presently, this has escalated into a multi-state epidemic, albeit with low incidences of infection among cattle in each state, characterized by temporary declines in milk output.