
A new H5N1 bird flu mutation has appeared in a cluster of infected dairy cows.
It's a genetic change that scientists say could not only make the virus more lethal, but increase its spread between mammals and possibly humans.
A new H5N1 bird flu mutation has appeared in a cluster of infected dairy cows.
It's a genetic change that scientists say could not only make the virus more lethal, but increase its spread between mammals and possibly humans.