Record U.S. Cyclospora Outbreak Is Over: CDC Confirms Largest Foodborne Illness Event in U.S. History

The largest outbreak of cyclosporiasis ever recorded in the United States is officially over, the Centers for Disease Control and Prevention (CDC) announced on September 11, 2026. The foodborne illness event, linked to shredded iceberg lettuce supplied from Mexico by Taylor Farms, sickened 12,883 people across 21 states, hospitalised at least 570 and caused two deaths — both in Michigan, the outbreak’s epicentre.

Public health officials describe it as the biggest and longest cyclospora season in U.S. history. Across the 2026 season, the CDC recorded 19,595 laboratory-confirmed cases of cyclosporiasis nationwide, making this the most widespread year for the parasitic infection on record. At the peak of the outbreak, more than 1,000 infections were reported in a single day. By August, after a nationwide recall, that figure had fallen to fewer than two infections per day.

Here is what happened, why the cyclospora outbreak proved so difficult to control, and what it means for food safety going forward.

What Caused the Record Cyclospora Outbreak?

Cyclosporiasis is caused by Cyclospora cayetanensis, a single-celled parasite that infects the small intestine. People become ill after consuming food or water contaminated with the parasite. Unlike many common stomach bugs, cyclospora is not spread directly from person to person — an infected person sheds the parasite in a form that needs time in the environment before it can infect someone else.

CDC and Food and Drug Administration (FDA) investigators traced the largest cluster to iceberg lettuce processed by Taylor Farms de Mexico, a central-Mexico-based processor. Epidemiologic and traceback data showed the lettuce was contaminated with cyclospora and made people sick. The contamination drove a multistate outbreak that was ultimately reported from 21 states, with Virginia added in the final update.

How the Outbreak Unfolded

The timeline behind this food safety alert shows how quickly a single contaminated ingredient can ripple through a national food supply:

• June 14, 2026 — The first illnesses linked to the outbreak began.
• July 17, 2026 — Taylor Farms de Mexico recalled the implicated iceberg lettuce, and restaurant chains including Taco Bell pulled shredded lettuce from their locations. Packages sold at retailers such as Walmart were also recalled.
• Late July and August — Case counts climbed steadily. Investigators identified a cluster of hundreds of cases across Michigan, Ohio, West Virginia and Kentucky that appeared to share a common food source.
• August 17, 2026 — The last onset dates linked to the multistate outbreak.
• September 11, 2026 — The CDC declared the outbreak over after a significant decline in recent infections and confirmed that the recalled products had passed their best-by dates and were no longer available in stores or restaurants.

The human and economic toll was significant. Beyond the hospitalisations and two deaths, the outbreak depressed sales of fresh lettuce and hit restaurants that serve shredded iceberg lettuce. It also intensified scrutiny of how the U.S. monitors imported produce and how quickly agencies can respond to contamination in the food supply.

Cyclosporiasis Symptoms: What to Watch For

Cyclosporiasis typically causes watery diarrhoea, and the symptoms can be severe enough to require medical care. According to the CDC and public health guidance, common signs include:

• Watery diarrhoea, sometimes alternating with constipation
• Loss of appetite and weight loss
• Stomach cramps, bloating and increased gas
• Nausea and fatigue
• Low-grade fever in some cases

Symptoms usually begin about one week after exposure, though the incubation period can range from roughly two days to more than two weeks. Without treatment, illness can drag on for weeks or even months, with symptoms that seem to improve only to return.

How Is Cyclospora Treated?

Cyclosporiasis is treatable. Doctors typically prescribe a course of antibiotics — most commonly trimethoprim-sulfamethoxazole, sold under brand names such as Bactrim — along with rest and plenty of fluids to manage dehydration. Because the illness is caused by a parasite rather than a virus or bacteria, common over-the-counter stomach remedies will not resolve the infection on their own.

Anyone who develops prolonged or severe diarrhoea after eating lettuce or other fresh produce should speak to a healthcare professional and mention possible exposure, so the right tests can be ordered. Stool testing is used to confirm cyclospora.

Why the Outbreak Was So Hard to Trace

Cyclospora presents a unique challenge for food safety investigators. The parasite’s long incubation period means people may not fall ill until weeks after eating the contaminated food, by which time the produce has often been eaten, discarded or spoiled.

Detection also takes time: it can take up to six weeks after symptoms begin for a case to be reported to public health authorities. The CDC noted that because of the unprecedented number of cases this season, some infections that occurred earlier may still be reported. That lag makes it difficult to spot an outbreak quickly and to pinpoint a source while the evidence is still fresh.

Adding to the complexity, the true number of sick people was likely higher than the confirmed count. Many people recover without seeking medical care and are never tested, and public health agencies only report laboratory-confirmed cases.

Cyclospora Prevention: Protecting Your Food Supply

While the contaminated lettuce is no longer on shelves, the outbreak is a reminder that food safety starts at home. Practical steps include:

• Wash hands, utensils and surfaces before and after handling fresh produce.
• Rinse raw fruits and vegetables thoroughly under running water before eating, cutting or cooking.
• Purchase produce from reputable suppliers and follow recall notices promptly.
• Refrigerate cut produce promptly and avoid leaving it at room temperature for long periods.
• Seek medical advice if you develop persistent diarrhoea after eating fresh produce.

Note that washing produce reduces risk but does not guarantee removal of cyclospora, which is one reason regulators focus on preventing contamination at the source.

What Happens Next

Although the outbreak is over, the FDA continues to investigate how the lettuce became contaminated with cyclospora, and it may publish further updates. The record season is also likely to feed into broader policy discussions about imported produce oversight, testing capacity and the resources available to food safety agencies. For consumers, the immediate takeaway is reassuring: the implicated products have expired and are no longer in circulation.

Frequently Asked Questions About the Cyclospora Outbreak

What is cyclospora?

Cyclospora is a microscopic parasite, Cyclospora cayetanensis, that infects the intestine and causes the diarrhoeal illness cyclosporiasis. It is spread through food or water contaminated with the parasite.

Is cyclosporiasis contagious from person to person?

No. Cyclospora is not transmitted directly from one person to another. The parasite must mature in the environment before it can infect someone, so person-to-person spread is not a concern.

How long does cyclosporiasis last?

Symptoms usually begin about a week after exposure and can last from several days to weeks or longer. Without appropriate antibiotic treatment, the illness can persist or recur for months.

Is the recalled lettuce still on sale?

No. The CDC confirmed that the recalled iceberg lettuce linked to Taylor Farms de Mexico has passed its best-by dates and is no longer available in stores or restaurants.

How many people were affected by the 2026 outbreak?

The multistate outbreak linked to the lettuce sickened 12,883 people across 21 states, with at least 570 hospitalisations and two deaths in Michigan. Overall, the 2026 season saw 19,595 laboratory-confirmed U.S. cases of cyclosporiasis — the highest on record.

What should I do if I think I was exposed?

If you develop prolonged diarrhoea or other symptoms after eating fresh produce, contact a healthcare provider. Mention any possible exposure to contaminated lettuce so that appropriate testing and treatment can be arranged.