Overview

• Highly pathogenic avian influenza H5N1 has been spreading among U.S. dairy cattle, with cases now reported in several states.
• Genomic analyses reveal the virus has been circulating undetected for months, likely originating from a single spillover event from birds.
• Transmission among cattle is likely facilitated by practices such as using poultry litter as feed and fertilizer, raising concerns about agricultural biosecurity.
• Limited human cases have been identified, with symptoms ranging from mild to severe, highlighting the risk of zoonotic transmission.
• Critics have voiced concerns over the slow governmental response and lack of transparency in data sharing, which may hinder efforts to control the outbreak.