H5N1 risk to dairy cows extends beyond US herd subtype
The Friedrich-Loeffler-Institut (FLI; Germany) is conducting an infection study to assess the susceptibility of dairy cows to the highly pathogenic avian influenza virus H5N1 (HPAIV H5N1). Initial findings indicate that both a US isolate (B3.13) and a recent H5N1 virus from a wild bird in Germany can replicate effectively in the udder. When the udder was directly infected through the teats, the dairy cows exhibited noticeable symptoms, including a significant reduction in milk production, altered milk consistency, and fever.
As a precaution, the FLI has tested approximately 1,400 bovine serum samples from cows in regions of Germany heavily impacted by avian influenza for antibodies and around 350 tank milk samples from various regions for virus genomes using PCR, all of which returned negative results. Further analyses of up to 1,500 tank milk samples are planned. It appears there is nothing unique about B3.13 that contributed to these infections.
