Cows in Nevada have been infected with a strain of H5N1 bird flu different from the strain detected in all other herds to this point in the ongoing dairy outbreak. It's the same strain that killed a Louisiana resident in early January and sent a Canadian teenager to intensive care in early November.
The new Nevada dairy infections were first detected through milk testing conducted on January 31, according to an update Wednesday by the US Department of Agriculture. Whole genome sequencing confirmed the finding of H5N1 clade 2.3.4.4b, genotype D1.1. To this point, all other dairy herds affected by the outbreak have been infected with H5N1 clade 2.3.4.4b, genotype B3.13.
To date, 957 herds across 16 states have been infected with H5N1 since the outbreak began last March. That tally includes four new herds from Nevada.