In its announcement this week of the first human death from bird flu in the United States, health officials in Louisiana were quick to note that the patient was over age 65 and “reported to have underlying medical conditions.

The death of a Louisiana resident who was over the age of 65 signals that future H5N1 infections are not guaranteed to be mild, health experts say

How deadly is the bird flu? The US has reported its first death from avian influenza, H5N1. Here's what to know about bird flu mortality rate and who is at risk.