This July 4th weekend, you may want to give those raw berries or green salad the side-eye.

That’s because a parasite that can contaminate raw produce and causes ferocious and long-lasting bouts of diarrheal illness is making people sick across several states.

Nationwide, 145 cases were reported by 17 states between May 1 and June 16, according to the US Centers for Disease Control and Prevention. At least 20 of those have been hospitalized, according to the CDC.

The agency says it’s typical for case counts to rise in the summer, and several states are reporting an unusually sharp jump in cases.

Michigan, which typically identifies around 50 cases of cyclosporiasis in a year, has reported at least 170 cases, clustered in 7 counties, over the past nine days, according to the state’s Department of Health. The state’s numbers do not appear to be included in the CDC’s count.