Monika Z Ballmann, Luca Bordes, Kim M Bouwman, Marc Y Engelsma, Sandra Venema-Kemper, Sylvia BE Pritz-Verschuren, Rene Heutink, Marit Roose, Marcel AH Spierenburg, Arco van der Spek, Hendrik IJ Roest and Evelien A Germeraad

Detection of antibodies against avian influenza in European dairy cattle, the Netherlands, January 2026

In December 2025, highly pathogenic avian influenza (HPAI) H5N1 clade 2.3.4.4b genotype DI.2.1 virus was detected in a cat living on a dairy cattle farm. Milk and serum samples from the dairy cattle were tested for avian influenza virus. No viral RNA was detected; however, H5N1-specific antibodies were identified in serum samples from 34 (47.2%) of 72 lactat