More than 200 cases of cyclosporiasis, a parasitic illness that can cause “explosive” diarrhoea, have been confirmed in Indiana as the CDC logs 1,645 cases across 34 states. Investigators suspect contaminated salad greens as the source of the outbreak.
Outbreak Details and Geographic Spread
The Centers for Disease Control and Prevention (CDC) reported on July 13 that 1,645 confirmed cases have been recorded across 34 states, with thousands more illnesses still under review. The outbreak's epicentre is the Midwest, particularly Indiana, which has recorded 206 confirmed cases. The highest concentrations are in the northwest, central, and northeast of the state, including 28 cases in Marion County, which covers the Indianapolis metro area.
Nearby states have been hit harder, with Michigan surpassing 3,300 cases and Ohio reporting more than 500, according to reports linked to the investigation. Health officials believe the parasite is spread when people consume food or water contaminated with infected human faeces.
Suspected Source and Investigation
The exact source of the 2026 outbreak remains under investigation, but authorities strongly suspect fresh lettuce or salad greens, as reported by The Hill. Past outbreaks have been linked to imported produce including raspberries, basil, cilantro, snow peas, and pre-packaged salad mixes. Notably, the parasite cannot be caught directly from another person; it needs days to weeks outside the body to become infectious, according to NPR.
The CDC also notes that Cyclospora can survive in chlorinated water features, although there is currently no evidence linking this outbreak to swimming pools.
Symptoms and Treatment
Symptoms usually strike about a week after exposure, ranging from two to 14 days, and can include watery, “explosive” diarrhoea, severe stomach cramps, bloating, loss of appetite, rapid weight loss, fatigue, and a low-grade fever. Without proper treatment, the illness can come and go for days to more than a month. Doctors are warned that routine stool tests can miss Cyclospora, meaning specific Cyclospora testing or molecular PCR tests may be needed, as reported by Infection Control Today.
The illness is treatable with a seven- to 10-day course of the antibiotic trimethoprim sulfamethoxazole (Bactrim or Septra). Around 9% of confirmed patients nationwide (141 people) have been hospitalised with severe dehydration, though no deaths have been reported.
Prevention Advice
Officials advise people not to stop eating fresh produce but to wash fruit and vegetables thoroughly under running water, scrub firm produce such as melons or cucumbers, and dry items with a clean paper towel. Heat destroys the parasite, so cooked vegetables and commercially frozen fruits have not been linked to the outbreak.
