Explosive Diarrhea Parasite Is Making People Sick Across the U.S. — Here's What to Know

Health officials are investigating a growing explosive diarrhea parasite outbreak after cases of a gastrointestinal illness caused by the parasite Cyclospora cayetanensis were reported in multiple states. While the source of the outbreak has not yet been identified, the U.S. Centers for Disease Control and Prevention (CDC) says the illness is seasonal and often linked to contaminated fresh produce.

The illness, known as cyclosporiasis, affects the small intestine and can leave people dealing with weeks of unpleasant digestive symptoms if left untreated.

The outbreak is being caused by Cyclospora cayetanensis, a microscopic parasite that spreads through food or water contaminated with human feces. Unlike many stomach bugs, Cyclospora is not typically spread from person to person because the parasite needs time to mature in the environment before it becomes infectious.

According to the CDC, investigators are working alongside state health departments and the U.S. Food and Drug Administration to determine whether the recent illnesses are connected to a single contaminated food source or several separate outbreaks. So far, no specific product has been identified.

Historically, Cyclospora outbreaks have been linked to fresh produce, including cilantro, basil, raspberries, lettuce, and bagged salad mixes.

The most commonly reported symptom is watery diarrhea with frequent — and sometimes explosive — bowel movements, but the parasite can cause a range of gastrointestinal issues.

Other symptoms may include:

• Stomach cramps
• Bloating and increased gas
• Nausea and vomiting
• Fatigue
• Loss of appetite
• Weight loss
• Low-grade fever

Symptoms usually begin about one week after exposure, although they can appear anywhere from a few days to two weeks later. Without treatment, the illness can last for several weeks or even longer, and symptoms may temporarily improve before returning.

While most healthy adults recover, dehydration can become a concern, particularly for older adults, young children, and people with weakened immune systems.

The CDC has confirmed cases across multiple states, with health officials noting that the true number of infections is likely higher than reported because many people never seek medical care or testing.

Michigan has seen one of the largest surges, with hundreds of confirmed cases reported in recent weeks. Other states, including Ohio and North Carolina, have also reported increases as investigators continue tracking the outbreak.

Because investigators have not yet identified the source of the outbreak, there is no way to avoid one specific food item. However, health experts recommend taking a few basic precautions:

• Wash fresh fruits and vegetables thoroughly under running water before eating them.
• Peel produce when possible.
• Cook produce when appropriate, since heat can help destroy the parasite.
• Wash hands before preparing or eating food.
• Drink safe, clean water, especially while traveling.

If you develop persistent watery diarrhea, especially after eating fresh produce or traveling, health experts recommend contacting a healthcare provider. Cyclosporiasis can often be treated with prescription antibiotics, and early treatment may help shorten the illness and reduce the risk of complications.