Cyclosporiasis Tracker 2026
Where Cases Have Been Reported
Shading shows how many CDC-confirmed cases lived in each state since May 1. The five states outlined in red are the Taco Bell lettuce outbreak — hover any state for both figures.
The two counts use different definitions and won't match. Ohio, for example, has 420 people sick in the Taco Bell outbreak but only 1–10 CDC-confirmed cases, because CDC's lab-confirmation pipeline runs well behind what states report. Cases are also not limited to the states shown — many people recover without ever being tested.
About Cyclosporiasis
What is cyclosporiasis?
Cyclosporiasis is an intestinal illness caused by a tiny parasite called Cyclospora cayetanensis. People get infected by swallowing food or water that has been contaminated with feces containing the parasite. It is far too small to see, and it cannot spread directly from one person to another. In the United States, outbreaks are usually traced to fresh produce such as leafy greens, herbs, and berries.
What are the symptoms?
The most common symptom is watery diarrhea that can last for weeks and often comes and goes. Other symptoms include loss of appetite, weight loss, stomach cramps, bloating, increased gas, nausea, tiredness, and a low-grade fever. Some people notice their symptoms seem to improve and then return. Symptoms usually begin about a week after swallowing the parasite.
How is it treated?
The recommended treatment is an antibiotic combination called trimethoprim-sulfamethoxazole, sold under brand names like Bactrim or Septra. For people who are allergic to sulfa drugs, ciprofloxacin is a less effective alternative. Without treatment, the illness can drag on for weeks or come back. Anyone with prolonged watery diarrhea should see a healthcare provider and ask specifically about testing for Cyclospora, since a standard stool test may not detect it unless the lab is told to look.
Sources: CDC About Cyclosporiasis · CDC Clinical Care · CDC 2026 Outbreak
Treatments & Vaccines in Development
Cyclosporiasis is treatable with a common antibiotic, but there is no vaccine and none close to human trials. Here's the treatment that works and where prevention research stands.
The recommended treatment for cyclosporiasis. A 7–10 day course clears the parasite and shortens the illness, which can otherwise drag on for weeks. For people allergic to sulfa drugs, ciprofloxacin is a less effective backup. The main problem is not the drug but the diagnosis — Cyclospora is missed unless the lab is specifically asked to look for it.
CDC Clinical Care →There is no vaccine for cyclosporiasis and none in human trials. Research is at the computer-modelling and lab stage — designing candidate targets from the parasite's proteins. Progress is slowed by a basic obstacle: scientists still cannot grow the parasite in the lab, so there is little material to work with. Prevention today rests entirely on food and water safety.
ScienceDirect →