H5N1 bird flu continues to evolve, threatening poultry, mammals and humans. Scientists track its spread and mutations, exploring strategies to prevent outbreaks and cross-species infections.
H5N1 bird flu found in cow's milk raises concerns about human transmission, though that hasn't happened yet. The virus reaches high levels in cow mammary glands. Other animals are also affected.
Rather, because the strain has spread so far and wide among birds — both wild and domesticated — there are simply more opportunities for mammals to be exposed, says virologist Emmie de Wit of the National Institutes of Health’s Rocky Mountain Laboratories in Hamilton, Mont.
