The Download: bird flu concerns, and tracking AI's impact on elections

Bird flu has been spreading in dairy cows in the US--and the scale is likely to be far worse than it looks. In addition, 14 human cases have been reported in the US since March. Both are worrying developments, say virologists, who fear that the country's meager response to the virus is putting the entire world at risk of another pandemic. Infections in dairy cattle, first reported back in March, brought us a step closer to human spread. Since then, the situation has only deteriorated. The virus appears to have passed from cattle to poultry on multiple occasions, and worse, this form of bird flu that is now spreading among cattle could find its way back into migrating birds.