With reports of the first human death from bird flu in the US, some Americans are feeling an uncomfortable flashback to the early days of Covid-19, when infectious disease experts were talking about a new virus that was sending people to the hospital with respiratory infections.

The first human death caused by H5N1 in the U.S. was reported in Louisiana on Jan. 6. Here's what to know about bird flu.

The national spread of the disease has alarmed public health officials, who remain concerned it could spread to humans on a large scale.