Federal health officials are investigating a growing outbreak of cyclosporiasis, a parasitic infection that can cause weeks of severe gastrointestinal illness. More than 1,000 cases have been diagnosed in Michigan and over 500 in Ohio, marking one of the largest outbreaks of its kind in Michigan's history and one of the country's largest in recent years.
Michigan officials reported over 1,200 cases and at least 40 hospitalizations as of the latest figures. In Ohio, northwest counties have identified more than 500 cases, with at least 306 in Lucas County. Texas has reported at least 48 cases, and illnesses have been noted in dozens of other states.
The Centers for Disease Control and Prevention (CDC) identified an uptick in infections in mid-June, with cases continuing to climb. The official outbreak season for the parasite typically runs from May 1 through August 31, coinciding with warmer temperatures.
Cyclosporiasis infections are characterized by watery, often "explosive" diarrhea that can persist for weeks or even months if untreated. Other symptoms include severe abdominal cramping, bloating, nausea, fatigue, and significant weight loss. While some infections may resolve on their own, treatment with antibiotics is frequently required.
The CDC, in conjunction with the Food and Drug Administration and state health officials, is actively investigating the multi-state clusters but has not yet identified a definitive source. Past outbreaks have been linked to contaminated fresh produce or irrigation water. Health officials recommend washing all produce thoroughly before consumption, though this may not eliminate the risk of infection. Michigan officials have advised consumers to purchase whole heads of lettuce rather than pre-washed bagged varieties and to wash lettuce leaves from the outer layers before preparation. Cooking vegetables when possible is also recommended.