An estimated 500,000 Americans have alpha-gal syndrome, a tick-borne allergy that can make eating red meat and other mammal-derived products trigger serious reactions.
Tick bites can sensitize the body to alpha-gal sugar found in most mammals, causing symptoms such as hives, nausea and vomiting that may not appear for 2 to 6 hours.
The delayed onset makes the condition hard to diagnose, and experts say it can also be triggered by pharmaceuticals, vaccines and some beauty products containing animal-derived ingredients.
The CDC says there is no cure, though over-the-counter test kits now exist and typically return results in 1 to 2 weeks.
Michigan health officials are watching the risk as Lone Star ticks spread, urging residents to avoid brushy habitat, use repellents and check for ticks after being outdoors.