Health officials are urging the public to take extra precautions after a growing outbreak of Cyclospora, a microscopic parasite that causes prolonged diarrhea, has sickened more than 1,400 people across multiple U.S. states.

Michigan has reported the largest number of infections, with more than 1,200 confirmed cases, while Ohio has recorded nearly 200 cases. Smaller increases have also been reported in New York, Illinois, Indiana, North Carolina, and Texas, though investigators are still determining whether all of the cases are connected. More than 40 people have required hospitalization.

Cyclospora infection, known as cyclosporiasis, is not usually life-threatening but can cause severe gastrointestinal illness. Common symptoms include watery diarrhea, stomach cramps, bloating, nausea, fatigue, loss of appetite, and dehydration. Unlike many common stomach viruses that resolve within a few days, Cyclospora infections can last for weeks or even months if left untreated.

Health experts say the parasite spreads through contaminated food or water rather than direct person-to-person contact. Fresh fruits, vegetables, herbs, and contaminated recreational water sources such as swimming pools, splash pads, lakes, and rivers have previously been linked to outbreaks. Because the parasite is resistant to chlorine, standard pool treatments may not completely eliminate the risk.

To reduce the chances of infection, experts recommend thoroughly cooking fresh produce whenever possible, as high temperatures effectively kill the parasite. Raw fruits and vegetables should be washed carefully under clean water for at least one minute before consumption. Firm produce should be scrubbed with a clean brush, while leafy vegetables should have their outer leaves removed before washing.

People at higher risk of severe illness, including older adults and those with weakened immune systems, may wish to avoid consuming raw produce commonly associated with previous Cyclospora outbreaks until health authorities identify the source of the current infections.

Anyone experiencing diarrhea lasting longer than 48 hours should seek medical attention. Standard laboratory tests may not routinely detect Cyclospora, meaning doctors may need to request specialized testing. Because the parasite is not always present in every sample, multiple stool tests may be required to confirm the diagnosis.