A fecal parasite that can contaminate food and water is causing “explosive” diarrhea across more than a dozen states, including Colorado, health officials said Tuesday.

Preliminary data show Colorado has recorded 90 cases of cyclosporiasis since January, Hope Shuler, a spokesperson for the Colorado Department of Public Health and Environment, said in an email.

That’s about 23% higher than this time last year, when Colorado had recorded 73 cases. The state reported 204 cases in all of 2025.

The five-year average in Colorado is 160.

“The majority of Colorado cyclosporiasis cases reported international travel,” Shuler said.

She added that Colorado cases are not clustered in any particular region of the state.

Nationally, about 145 cases in 17 states — including Colorado — were reported to the Centers for Disease Control and Prevention (CDC) during the first six weeks of cyclosporiasis season, which starts May 1 and typically runs through the end of summer.

The national and Colorado figures cover different time periods.

Colorado’s count includes cases reported since January, while the CDC figure covers cases reported since May 1.

States reporting cases include Texas, Florida, Illinois, Pennsylvania and New York.

Health officials believe the actual number of cases is likely higher because some people may have recovered without seeking medical care or being tested.

Those sickened range in age from 5 to 86. The median age is 42, and six in 10 are female.

No deaths have been reported.

Colloquially referred to as “cyclo,” cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis.

The most common symptom is watery diarrhea with frequent “explosive” bowel movements, according to the state Health Department. Other symptoms can include loss of appetite, weight loss, increased gas, abdominal cramps, bloating, nausea and fatigue.

Vomiting, body aches, headaches and other flu-like symptoms may also occur.

The incubation period averages about seven days but can range up to 14 days or longer. If left untreated, symptoms can linger for a month or longer.

People become infected by ingesting food or water contaminated with the parasite.

The parasite found in stool is not immediately infectious, meaning person-to-person transmission is unlikely.

In the U.S., previous outbreaks have been linked to fresh produce, according to the CDC. Cyclosporiasis is typically treated with a combination antibiotic known as TMP-SMX, along with rest and hydration.

The CDC recommends washing hands with soap and water before and after handling or preparing raw fruits and vegetables.

Consumers should also thoroughly wash fruits and vegetables and scrub firm produce, such as melons and cucumbers, with a clean produce brush. Damaged or bruised areas should be cut away before preparing or eating produce.

Washing produce can reduce contamination but may not completely eliminate Cyclospora.