This tick can give you a life-threatening allergy. It’s spreading across the U.S.

Peak tick season is here — and the fastest-growing tick-borne illness in the country is alpha-gal syndrome, a condition that causes an often-severe allergy to red meat and other animal products. It’s primarily spread by lone-star ticks, once confined to the Southeast but now found as far north as Maine and Michigan. The syndrome can trigger a range of reactions — from hives to anaphylaxis — and at least one death has been attributed to it. New Yorker staff writer Burkhard Bilger, who has reported on the syndrome’s rise, joins Apple News In Conversation guest host David Greene to explain how it was discovered, why it can take years to diagnose, and how it’s reshaping the way people eat, work, and spend time outdoors.