A large multistate outbreak of cyclosporiasis that has been tied to lettuce sold at restaurants such as Taco Bell and some grocery stores now accounts for cases across 15 states, according to federal health officials.

US cyclosporiasis cases have reached record levels this year, with the current epidemic among the largest foodborne illness outbreaks in recent US history.

The outbreak is linked to lettuce served at Taco Bell and sold in grocery stores, but it’s unlikely all of the cyclosporiasis cases were caused by a single item.