Health officials are monitoring an increase in cases of cyclosporiasis, a parasitic infection causing severe watery diarrhea, across Texas and 16 other states this summer.
As of mid-June 2026, the Centers for Disease Control and Prevention reported 145 confirmed domestic cases nationwide, with Texas recording between 11 and 30. Denton County Public Health has confirmed two cases, while officials note the local impact remains limited. Collin County has also reported two cases. No single source has been identified, and investigations into potential clusters continue.
The microscopic parasite Cyclospora cayetanensis spreads through contaminated food or water, often linked to fresh produce such as cilantro, basil or berries in past outbreaks. Symptoms typically appear about a week after exposure and can include watery diarrhea, loss of appetite, weight loss, cramping, bloating, nausea and fatigue. The illness is generally not life-threatening for healthy people but can last weeks or longer without treatment and may recur. Twenty people have been hospitalized nationwide, with no deaths reported.
The Texas Department of State Health Services issued a health advisory in May urging clinicians to watch for symptoms, especially in immunocompromised patients who face higher risks. Most cases occur seasonally between May and August. Direct person-to-person transmission is unlikely because the parasite needs time in the environment to become infectious.
Prevention focuses on food safety: wash hands before handling produce, rinse fruits and vegetables thoroughly under running water, and scrub firm items like melons. Pre-washed items do not need additional washing at home. Those with symptoms lasting more than a few days should see a doctor. Trimethoprim-sulfamethoxazole is the standard treatment for those who need it.
The CDC continues to work with state health departments and the FDA to trace possible sources while reminding the public that many mild cases may go unreported.
No single contaminated food item has been confirmed in the current cluster of cases.
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