How fast is bird flu spreading in US cows? ‘We have no idea’

Avian flu is spreading rapidly among cattle, but public health and infectious disease experts are concerned the United States is too limited in its testing, leaving an incomplete picture of the virus’s spread.  

The threat to the general public is currently low, health officials say, and the country’s milk supply is safe. Just one person has been infected. ...

But the outbreak is widespread; officials have found the virus in 42 herds across nine states. Dairy farm workers are at risk every time they are exposed to potentially infected cattle, and viral mutations could cause an outbreak, experts warn.  

...