Federal health officials are searching for the source of a microscopic parasite that has left Americans suffering from intense gastrointestinal illness as infections begin to spike this summer.

The Centers for Disease Control and Prevention has confirmed 145 cases of cyclosporiasis across 17 states as of mid-June 2026. All confirmed infections were acquired within the United States.

The illness is caused by Cyclospora, a parasite that triggers cyclosporiasis.

The CDC notes that the infection’s signature symptom is watery and often “explosive” diarrhea that can persist for weeks or even months without treatment.

Patients commonly experience abdominal cramps, bloating, nausea, fatigue and weight loss as part of the infection’s course.

The CDC says the official outbreak season runs from May 1 through August 31, a stretch when warmer conditions typically coincide with higher infection rates.

Cases have appeared across the country, from Texas to Alaska. New York has been the hardest hit so far, reporting between 31 and 80 cases, while Texas and Illinois have recorded between 11 and 30 each.

Although some infections may resolve on their own, many patients require antibiotics to recover, according to federal officials.

Of the 145 confirmed cases, 20 have led to hospitalization. No deaths have been reported to date.

Patients’ ages range from 5 to 86 years old, with a median age of 42. Women represent 61 percent of confirmed cases.

The CDC has joined forces with the Food and Drug Administration and state health departments to investigate multiple clusters of the illness.

However, investigators have yet to identify a single cause linking all infections.

“There is currently no evidence of a single, multistate Cyclospora outbreak linking all cases,” the CDC stated in its recent surveillance summary.

Officials continue to urge anyone experiencing symptoms of cyclosporiasis to seek prompt care and testing through a healthcare provider.

The agency’s latest data show that the parasite’s annual cycle mirrors a predictable seasonal curve, but this year’s geographic spread is drawing additional scrutiny.

Experts emphasize that understanding the infection sources is vital for prevention, especially as summer temperatures rise and case counts climb.

Public health teams are currently monitoring trends in produce distribution and supply chains, while laboratories analyze stool samples and genetic sequences to track parasite patterns.

Federal investigators say more findings will be shared as laboratory testing and traceback efforts continue over the coming weeks.

For now, the CDC’s message remains consistent: awareness, early diagnosis, and communication with local health departments are key to halting further spread of the illness.