A strain of avian flu has been circulating among dairy cows for nearly five months
Lauren Justice/Bloomberg via Getty Images
US health officials are struggling to monitor people for avian influenza, a virus that is spreading among dairy cows. Lack of surveillance means human infections may go undetected, making it difficult to contain the virus’s spread. This could allow the pathogen to mutate and become more dangerous to people.
The virus, a type of avian influenza known as H5N1, has killed millions of birds and thousands of mammals around the world.
