Cyclospora, ‘Explosive Diarrhea’ & Fresh Produce: What to Know

July 13, 2026

An intestinal infection that causes “explosive diarrhea” has been spreading across several U.S. states this summer. Called cyclosporiasis, the infection has sickened at least 3,000 people so far.

“Cyclosporiasis is usually not life-threatening, but the symptoms can be very uncomfortable,” says gastroenterologist Brooke Glessing, MD, GI Medical Director at University Hospitals Ahuja Medical Center. “In severe cases, the illness can even lead to hospitalization.”

What Is Cyclosporiasis?

Cyclosporiasis is an infection caused by a microscopic parasite called cyclospora. Previous outbreaks have been linked to eating fresh produce or drinking water that has been contaminated by human feces containing the parasite. Although cases of cyclosporiasis appear each year from May through August, the recent surge is especially large.

Cyclospora is resistant to bleach, which means it can survive in chlorinated water used in swimming pools, splash pads and water parks. It also lives in lakes and rivers.

What Are the Symptoms?

The main symptom of cyclosporiasis is watery or “explosive” diarrhea. This type of diarrhea involves passing liquid or loose stool more frequently and forcefully than regular diarrhea.

Other symptoms of cyclosporiasis include:

Cramping
Bloating
Increased gas
Loss of appetite
Weight loss
Nausea
Fatigue

Symptoms can develop days and even weeks after ingesting infected food or water. Less common symptoms may include body aches, headache, vomiting, low-grade fever and other flu-like symptoms.

“Most people recover from common gastrointestinal illnesses, such as norovirus, within a day or two,” says Dr. Glessing. “Cyclosporiasis is different. Symptoms can last for weeks or even months, often improving for a time only to return.”

How Many People Are Infected?

The current cyclosporiasis outbreak has reportedly affected at least 3,000 people so far. Michigan appears to be the epicenter, where more than 2,600 cases have been reported. Ohio, New York, Illinois and North Carolina are other states that have reported more than 100 cases.

About 30 states have reported cases of cyclosporiasis although not all of these cases may be a part of the same outbreak.

“Because some people recover from the illness without getting medical care, the actual number of cases is likely much higher than what is reported,” says Dr. Glessing.

Who Is Most at Risk to Get Sick?

While anyone can contract the illness, health officials warn that people with a higher risk of becoming dehydrated and those with weakened immune systems should be extra cautious during the outbreak. Infants, young children and elderly people are most at risk for experiencing severe or prolonged illness due to cyclosporiasis.

How to Reduce Your Risk of Getting Sick

Here are steps you can take to reduce your risk of contracting the illness:

Wash all fresh produce thoroughly, even fruits and vegetables that will be peeled. Rinsing produce is always a good food safety practice, but it may not eliminate the Cyclospora parasite.
Choose produce with a thick rind, such as melons, pineapple and squash. Wash it thoroughly before cutting into it.
Eat cooked fruits and vegetables instead of raw food whenever possible. A temperature of 158 degrees Fahrenheit or higher kills cyclospora.

As of early July 2026, authorities have not traced the current outbreak to a specific grower, supplier or type of produce. However, past outbreaks in the U.S. and Canada have involved foods that are harder to wash thoroughly, including:

Bagged salad mixes (pre-cut lettuce blends with romaine, iceberg, red cabbage and carrots)
Raspberries
Berry/fruit mixes
Basil
Cilantro
Snow peas

“Thoroughly washing all produce, cooking it or temporarily avoiding fresh produce if you’re at risk for more severe illness can reduce your chances of infection,” says Dr. Glessing.

Other tips to reduce your risk include:

Wash your hands for 20 seconds with warm water and soap before and after handling fresh produce.
Cut off damaged or bruised areas of produce before preparing or eating.
Scrub firm vegetables and fruits with a soft brush when rinsing.
Break off and discard the outermost leaves of the heads of lettuce and cabbage.

“Also, if there’s an outbreak near where you live, you may want to avoid public swimming areas or at least be extra careful not to swallow water,” says Dr. Glessing.

What to Do If You’re Sick

Experts recommend seeing a doctor for a diagnosis and treatment if you’ve had diarrhea for longer than 48 hours.

Depending on your symptoms, your doctor may test you for cyclosporiasis, which is done by taking a stool sample. Because cyclospora eggs shed from the body inconsistently, you may need as many as three tests spaced 24 hours apart to obtain an accurate diagnosis.

Cyclosporiasis is treated with the combination antibiotic sulfamethoxazole-trimethoprim, which is sold as Bactrim or Septra, for 7 to 10 days.