Tick-borne affliction, informally

LYME

["This bacterial infection often starts with a bullseye-shaped rash and is named after a Connecticut town where it was first identified."]

This clue hints at a disease spread by ticks, using "informally" to signal a casual or shortened name. "Lyme" refers to Lyme disease, a bacterial infection transmitted through tick bites, often associated with symptoms like rash and fatigue. The wordplay is straightforward—no tricks—just a common nickname for the condition.