Cyclospora Outbreak Linked to Iceberg Lettuce Spreads to Nine States

A multistate Cyclospora outbreak linked to iceberg lettuce has spread to nine states, with the CDC confirming more than 4,000 laboratory cases since May 1, 2026.

The affected states are Illinois, Indiana, Kansas, Kentucky, Michigan, Ohio, Oklahoma, Pennsylvania, and West Virginia. The CDC is investigating thousands of additional potential infections beyond the confirmed laboratory cases.

Cyclospora cayetanensis is a microscopic parasite that causes an intestinal illness called cyclosporiasis. Symptoms include watery diarrhea, loss of appetite, weight loss, stomach cramps, nausea, fatigue, and low-grade fever. The illness can last from a few days to several weeks if not treated.

Health officials linked the outbreak to iceberg lettuce through epidemiological investigation. Consumers are urged to check the source of their produce and avoid iceberg lettuce from affected supply chains until the investigation is complete.

The outbreak was reported by the Urgent Care Association and the National Community Pharmacists Association in their July 30, 2026, news roundups. The CDC has not yet identified a specific brand or distributor responsible for the contaminated lettuce.

Cyclospora outbreaks in the United States have previously been linked to fresh produce including raspberries, basil, snow peas, and various types of lettuce. The parasite is typically spread through food or water contaminated with feces.

Treatment with the antibiotic trimethoprim-sulfamethoxazole is effective. People who develop symptoms after eating iceberg lettuce are advised to contact their healthcare provider.