The virus is poised to become a permanent presence in cattle, raising the odds of an eventual outbreak among people... So far, this virus, H5N1, does not easily infect humans, and the risk to the public remains low. But the longer the virus circulates in cattle, the more chances it gains to acquire the mutations necessary to set off an influenza pandemic. Source: The New York Times - How U.S. Farms Could Start a Bird Flu Pandemic