Washington man thought to be first to die from rare strain of bird flu

This undated electron microscopic image provided by the Centers for Disease Control and Prevention shows two Influenza A (H5N1) virions, a type of bird flu virus. (Cynthia Goldsmith, Jackie Katz/CDC via AP) - (ASSOCIATED PRESS)

A man in Washington state is believed to be the first human to die from a rare strain of bird flu.

The individual, an older adult with pre-existing health conditions, was being treated for the H5N5 bird flu strain, marking the first known human infection.