Jeff “Bama” Tunnicliff had been working hard – shoveling and pounding posts into the ground. He figured his upper body aches were related to that and didn’t think too much of it.

The cough, he thought, was a result of the haze and smoke coming from the state’s second-largest wildfire in history north of Grand Junction. Like most other folks in these parts, he sleeps with the windows open and doesn’t have air conditioning.

The 33-year-old thought he was just congest...