The recent discovery of H5N1 (avian flu) in the US dairy herd creates more questions than answers. Since 2020, the highly pathogenic bird flu has been spreading across the globe, posing an existential threat to birds and wildlife. The virus has infected birds in more than 80 countries (as of December 2023) and has resulted in the culling of millions of chickens and turkeys at commercial poultry farms. Questions come to mind whether dairies in other countries have had bird flu undetected in their herds or if the recent discovery of bird flu in the USA dairy herd is a new localized phenomenon. If so, why only the US dairy herd? (Bird flu is yet to be discovered in Oceania). Milk pasteurization is said to kill the virus allowing the milk to be apt for human food applications. However, the science behind this and proof of such hasn't been published yet. One detail we do know, however is that the viral presence in the dairy herd causes cows to produce less milk. Anecdotal data from Texas anticipates ~ 3-5% effect on regional milk production. Virus cultures have been positive in cow's milk but not in cow's blood or noses, so it appears to be “actively replicating” only in their udders at this time. Sources:
H5N1 Avian Influenza's Flight to Cattle, and Beyond | American Council on Science and Health (acsh.org)