Cyclosporiasis Outbreak in the United States has officially been declared over after becoming the largest recorded multistate outbreak of the intestinal illness. U.S. federal health officials announced on September 11, 2026, that the outbreak linked to processed iceberg lettuce from Taylor Farms de Mexico had ended. The contaminated lettuce was supplied from central Mexico and was connected to thousands of infections reported across several U.S. states.

The outbreak affected 12,883 people across 21 states. It also resulted in 570 hospitalisations and two deaths, with both deaths reported in Michigan. Health authorities had been monitoring the outbreak for several months while investigating the source of the infections and taking steps to remove the suspected food product from the market.

What Is Cyclosporiasis?

Cyclosporiasis is an intestinal infection caused by a microscopic parasite called Cyclospora cayetanensis. People can become infected when they consume food or water contaminated with the parasite.

The illness mainly affects the digestive system. Common symptoms include watery diarrhoea, loss of appetite, stomach cramps, nausea and tiredness. Symptoms can sometimes continue for weeks and may return after appearing to improve.

The infection is generally associated with contaminated fresh produce and other foods. Because the parasite can spread through contaminated food and water, food safety and proper handling are important in preventing infections.

Lettuce Linked to the Outbreak

The major Cyclosporiasis Outbreak was linked to processed iceberg lettuce supplied by Taylor Farms de Mexico. The lettuce was sourced from central Mexico and distributed for consumption in the United States.

After investigating the outbreak, food safety officials identified the lettuce as the suspected source connected to the infections. Taylor Farms responded by recalling iceberg lettuce sourced from central Mexico on July 17, 2026.

The recall was an important part of the response because removing potentially contaminated products from stores and food-service operations can help prevent additional infections.

By September 11, officials said the recalled products were no longer on the market and had passed their best-by dates. This allowed federal health authorities to declare the specific multistate outbreak over.

Thousands of Infections Reported

The Cyclosporiasis Outbreak was significant because of the large number of infections reported in multiple states. According to federal health data, 12,883 infections across 21 states were connected to the lettuce-linked outbreak.

Michigan was among the most severely affected areas. The state reported more than 14,000 cases and two deaths, according to the information released during the outbreak response.

Illinois, Indiana and Ohio were also among the states reporting major impacts. The spread across multiple states made the investigation more complicated because health officials had to compare laboratory results, patient information and food exposure histories from different locations.

Wider Cyclosporiasis Cases in 2026

The lettuce-linked outbreak was part of a much larger picture of cyclosporiasis infections in the United States during 2026.

Since May 1, 2026, the U.S. Centers for Disease Control and Prevention recorded 19,595 laboratory-confirmed cases of cyclosporiasis acquired in the United States. These cases were reported across 49 states and Washington, D.C.

During the same period, health authorities recorded 1,043 hospitalisations and two deaths.

The figures were considerably higher than the number reported during the comparable period in 2025. Between May 1 and August 31, 2025, only 1,180 cases had been reported. The increase in 2026 highlighted the importance of continued disease surveillance and food safety investigations.

Health Symptoms and Treatment

People infected with Cyclospora cayetanensis may develop symptoms several days after consuming contaminated food or water. The most common symptom is prolonged watery diarrhoea.

Other symptoms may include stomach cramps, nausea, loss of appetite, weight loss and fatigue. Some people may experience symptoms for an extended period if the infection is not properly treated.

Healthcare professionals can diagnose cyclosporiasis through laboratory testing. Treatment is available, and medical advice is important for people experiencing persistent diarrhoea or other serious digestive symptoms.

People who develop severe symptoms may also face dehydration, especially if diarrhoea continues for a long time. Drinking enough fluids is therefore an important part of managing diarrhoeal illness.

Food Recall and Safety Measures

The food recall played a major role in the response to the Cyclosporiasis Outbreak. Taylor Farms recalled all iceberg lettuce sourced from central Mexico on July 17.

Food recalls are used when authorities or companies identify a product that could pose a health risk. Removing the product from stores, restaurants and other food-service locations helps reduce the possibility of additional exposure.

Federal officials said the recalled lettuce was off the market by September 11 and had passed its best-by dates. This was one of the factors supporting the decision to declare the outbreak over.

However, ending an outbreak does not mean that all investigations stop immediately. Health authorities continued examining how Cyclospora may have entered the food supply and whether other clusters reported during the summer of 2026 had separate sources.

FDA Continues Investigation

The U.S. Food and Drug Administration (FDA) continued its investigation into the source of the contamination. Officials were examining how the parasite may have entered the food supply associated with Taylor Farms de Mexico.

The FDA was also looking into other cyclosporiasis clusters reported during the summer. These investigations are important because different clusters can have different sources, even when they occur during the same period.

Investigators may use laboratory testing, food distribution information, patient interviews and other evidence to identify possible links between infections and contaminated products.

Importance of Food Safety

The Cyclosporiasis Outbreak has once again highlighted the importance of food safety throughout the food supply chain. Fresh produce can become contaminated at different stages, including during farming, harvesting, processing, transportation or preparation.

Consumers can also reduce the risk of foodborne illness by following safe food-handling practices. Washing hands before preparing food, keeping food preparation areas clean and following proper storage instructions are important steps.

For food producers and suppliers, maintaining safe production and processing systems is essential. When a possible contamination problem is identified, rapid investigation and product recalls can help limit its impact.

Outbreak Declared Over, Monitoring Continues

Although federal officials declared the largest multistate Cyclosporiasis Outbreak over on September 11, 2026, health authorities continued monitoring cases and investigating other reported clusters.

The outbreak demonstrated how a contaminated food product can affect people across many states and create a major public health investigation. Laboratory confirmation, state-level reporting, food tracing and product recalls were important parts of the response.

The investigation into the 2026 cyclosporiasis cases also remains important for understanding how Cyclospora contamination can enter the food supply and how future outbreaks can be detected and controlled more quickly.