[quote]The outbreak of H5N1 bird flu in US dairy cows has now spread to three herds in California, the largest milk-producing state in the country with around 1.7 million dairy cows. Fourteen states and 197 herds have now been affected by the unprecedented outbreak in dairy cows, which was first confirmed by federal health officials on March 25.
[quote]The herds in California are thought to have been infected through the movement of cattle, despite a federal order mandating testing of cattle prior to movement between states. So far, health officials believe that all of the dairy infections across the affected states stem from a single spillover event from wild birds to dairy cows in Texas. The virus is thought to spread from cow to cow, as well as from contaminated milking equipment, dirty hands, and boots.