mGem: Transmission and exposure risks of dairy cow H5N1 influenza virus.

Abstract

In March 2024, highly pathogenic H5N1 was detected in dairy cows; as of 12 December 2024, it had spread to over 800 herds in 16 states. The ongoing outbreak is a public health crisis affecting both humans and animals, as interspecies transmission has emerged as a common characteristic of this virus. As of 12 December 2024, >30 humans have been infected in the United States related to dairy cow exposure. In this mGem, we discuss transmission modalities between cows within herds, the spread of the virus between dairy farms, and exposure risks for humans. We also highlight major gaps in knowledge constituting barriers to our ability to effectively control the spread of H5N1 in dairy cows and reduce the risks to humans.