A pig on an Oregon farm tested positive for bird flu for the first time in the U.S. on Oct. 30, concerning virologists because pigs have been a source of prior human pandemics. The USDA said on Nov. 6 that a second pig on the farm had also tested positive.

The general public health threat remains low, but some infectious disease experts worry about a thinning line that's kept bird flu from spreading between people.

A suspected case of bird flu is under investigation in Gibson County. President-elect Donald Trump has pledged to shake things up in Washington in his second term. Here are the two main changes he wants to make to Social Security.

The H5N1 bird flu outbreak in the U.S. has so far been shockingly mild. Researchers have some theories as to why.