Parasite that causes explosive diarrhea detected in El Paso, but risk remains low

by Priscilla Totiyapungprasert

El Paso health officials have confirmed one case of cyclosporiasis, an intestinal illness caused by a parasite, this year. The report comes during a multi-state outbreak that has prompted the Federal Drug Administration to investigate contaminated produce.

The cyclospora parasite, known for causing severe diarrhea, is not new to the region. Isolated cases of cyclospora infections occur each year in El Paso, said Dr. Hector Ocaranza, city and county health authority. The El Paso Department of Public Health is monitoring the situation and the level of concern for the community remains low, he said.

This year’s case, a man in his 60s, was reported to city epidemiologists June 16. The man was not hospitalized and epidemiologists did not identify a confirmed source of exposure. This was the first case of cyclosporiasis reported in El Paso since July 2025.

The Centers for Disease Control and Prevention reported 1,645 cases across 34 states, including Texas, as of July 13. But national reporting lags significantly behind state reporting, resulting in an undercount of cases.

“Because no single source has yet been identified, the investigation remains active and continues to receive significant attention,” Ocaranza said.

What is cyclospora?

Cyclospora is a microscopic parasite that infects the small intestine, causing watery and explosive diarrhea. The parasite spreads when people eat raw produce or drink water contaminated by infected feces. Unlike other stomach bugs, cyclosporiasis does not transmit directly from person to person.

The parasite is endemic to tropical and subtropical regions. Cases tend to rise in the summer because cyclospora requires a warm environment to mature to an infectious stage, it is the peak season for many fruits and vegetables, and people are spending more time in pools, lakes and splash pads.

Many people recover from cyclospora infections without seeking medical care, which contributes to the undercount of cases, Ocaranza said. 

Diagnosing cyclosporiasis requires health care providers to order a stool test, which is not routine. The diarrhea caused by cyclospora often cannot be distinguished from other common gastrointestinal illnesses, such as norovirus or rotavirus, based on symptoms alone, Ocaranza said.

What makes the parasite infections so bad this year?

A sudden surge in cyclosporiasis cases and hospitalizations, starting in the Midwest, has stumped investigators and revealed gaps in surveillance. More than 3,000 cases have been reported in Michigan and Ohio alone, where contaminated lettuce is a suspected source, but state health officials have not identified a specific type, grower or supplier.

In July 2025, the Trump administration scaled back the CDC’ Foodborne Diseases Active Surveillance Network and made monitoring cyclosporiasis optional for states, though Texas continues to report cases as a notifiable condition. The administration last year also made massive budget and staffing cuts to the FDA, the agency in charge of investigating foodborne illness outbreaks along with the CDC and U.S. Department of Agriculture.

The CDC and FDA did not immediately respond to requests for comment.

How can I protect myself from the diarrhea outbreak?

The El Paso Department of Public Health recommends the following measures to reduce the risk of cyclospora infection and spread:

• Wash fresh fruits and vegetables thoroughly under running water before consumption.
• Cook foods to their recommended internal temperatures.
• Avoid drinking untreated water from recreational or natural water sources, including lakes and creeks.
• Wash your hands thoroughly before preparing or eating food and after using the restroom.
• Avoid swimming or participating in recreational water activities if you are experiencing gastrointestinal symptoms.
• When traveling, use caution when consuming raw produce or food from unregulated street vendors.
• If you develop persistent gastrointestinal symptoms, contact your healthcare provider and be sure to share any recent travel history, particularly to areas experiencing outbreaks or where cyclospora is endemic.
• If you care for someone with a weakened immune system, avoid providing care while experiencing gastrointestinal symptoms.

Ocaranza said the health department is conducting outreach with healthcare providers. 

If patterns or potential sources of illness are identified, the department may coordinate with the city’s Food Inspection Division to collect samples for testing and request help from the state health department’s rapid response team, which investigates food contamination, traces the source of infection in outbreaks and implements measures to control transmission.