At least 843 Americans have been diagnosed with cases of cyclosporiasis, a gastrointestinal disease that causes severe diarrhea, since the beginning of May.

The illness has been reported in 31 states and has hospitalized 86 people as of Thursday, July 9, according to statistics reported to the Centers for Disease Control and Prevention. Another 1,500 instances could possibly be cyclosporiasis but require further analysis, as the CDC said the “true number” of cases is likely higher than the reported number.