A One Health Investigation into H5N1 Avian Influenza Virus Epizootics on Two Dairy Farms.

This article focuses on the investigation of highly pathogenic avian influenza virus (HPAIV) H5N1 infections in two Texas dairy farms during early 2024. Using molecular assays, virus culture, and genomic sequencing, researchers detected H5N1 HPAIV in a majority of milk samples (64%) but rarely in cattle nasal swabs (2.6%), with no viral RNA found in farm workers' nasopharyngeal swabs; however, 14.3% of tested workers had neutralizing antibodies against a related H5N1 strain, indicating possible exposure. The viral isolates belonged to clade 2.3.4.4b and contained mutations linked to increased spillover potential. Additionally, SARS-CoV-2 RNA was unexpectedly identified in a nasal swab from a sick cow. The study highlights the need for expanded surveillance and collaboration with dairy farms to better understand H5N1 epidemiology and to develop effective interventions while protecting agricultural interests.