Cyclospora Cases Are Rising, But These Stomach Bugs Are Far More Common

The CDC is tracking a major cyclosporiasis outbreak, with over 1,600 confirmed cases across 34 states by mid-July 2026, nearly six times last year's figures. Over 5,000 additional cases are under review, and contaminated lettuce sold to Taco Bell is a suspected source. While norovirus, salmonella, and campylobacter are more common causes of diarrheal illness, cyclosporiasis is distinct. Its symptoms, including watery diarrhea, fatigue, and weight loss, can persist for weeks and relapse. It's linked to fresh produce, not meat, and often requires specific testing as routine stool cultures miss it. Cases are most common from May to August. If experiencing persistent, watery diarrhea with fatigue after eating fresh produce, individuals should ask their doctor about Cyclospora testing. Basic food safety, like washing produce and hands, is crucial.

The Centers for Disease Control and Prevention is tracking a major outbreak of cyclosporiasis, a diarrheal illness caused by the parasite Cyclospora cayetanensis. As of mid-July, the CDC has confirmed more than 1,600 cases across 34 states, with over 5,000 additional cases still under review.

This total is nearly six times higher than this point last year. Contaminated lettuce sold to Taco Bell is among the suspected sources of the outbreak.

But cyclosporiasis is far from the only infection that can cause diarrhea and gastrointestinal disease. Most acute diarrheal illnesses in the U.S. are not caused by Cyclospora, but by one of these common culprits.

Norovirus is the most common cause of acute gastroenteritis in the U.S., responsible for an estimated 19 to 21 million cases each year. It spreads efficiently from person to person and through contaminated food, especially in group settings like cruise ships, schools and restaurants. Symptom onset is rapid — often within 12 to 48 hours of exposure — and typically include vomiting, watery diarrhea and cramping. Fortunately, most infected individuals recover within one to three days.

Salmonella is a bacterial infection usually linked to undercooked poultry and eggs, unpasteurized dairy or contaminated produce. It can cause a fever, stomach cramps and diarrhea that typically start six hours to six days after exposure and generally resolve within a week after symptom onset. Blood in the stool and higher fevers are more common than with norovirus.

Campylobacter is another leading cause of bacterial gastroenteritis and food-borne illness, usually associated with undercooked poultry, raw milk or contaminated water. The CDC estimates that Campylobacter causes over 1.5 million cases each year, although many cases remain undiagnosed. Symptoms usually start two to five days after exposure and can include cramping, a fever and diarrhea that may be bloody. In contrast to norovirus infection, diarrhea resulting from Campylobacter may last for a week, or even longer.

Given the current outbreak, it’s worth knowing what makes cyclosporiasis different from other more common causes of gastrointestinal disease:

Due to the number of pathogens that can cause diarrhea and the nonspecific clinical presentation, it can be challenging to know what is causing gastroenteritis. If your diarrhea is watery, keeps coming back over more than a week and is associated with significant fatigue and/or weight loss — particularly if you’ve recently eaten fresh salad greens, herbs or berries — it’s worth asking your doctor if you should be tested for Cyclospora.

Regardless of the cause, the same food safety steps can help reduce your chances of coming down with a very unpleasant illness. These steps include washing produce thoroughly, cooking food to the recommended internal temperature, avoiding unpasteurized dairy and washing your hands with soap and water after using the bathroom and before preparing or eating food.