The highly contagious illness is linked to a parasite, usually found in food or water.
Illinois health officials say they're seeing an uptick in cases of cyclosporiasis.
So far 141 cases are confirmed statewide.
Of those, 62 reported travel outside the U.S., 59 were domestically acquired and 20 cases are pending investigation to determine travel status.
The epicenter of the outbreak seems to be Michigan.
Kristin Gustashaw is a clinical dietician at Rush. She shared some ways to keep from getting sick Tuesday.
"IDPH is seeing a higher-than-average number of reported cases of cyclosporiasis, consistent with what is being seen in several other states. It can be contracted by consuming food or water contaminated with feces. At this point, no single source or cause of this increase has been identified, and there is no evidence of a large outbreak accounting for all or most of these cases. IDPH continues to work with the CDC and other public health partners to look for trends. In the meantime, IDPH recommends following all guidelines for safe food handling, including washing produce (wash all fruits and vegetables under running water before eating, cutting, or cooking; scrub firm produce such as melons and cucumbers with a clean produce brush)," the Illinois Department of Public Health said.