The CDC is warning of an increase in cyclosporiasis cases. Here’s what you need to know:
Cases of cyclosporiasis are increasing across the United States as authorities warn of contaminated produce and symptoms.
Cases of the disease caused by a parasite that causes explosive diarrhea continue to spread across the United States, with hundreds of cases surging and authorities trying to track them down.
Cyclosporiasis, a painful illness caused by a parasite commonly found in produce and herbs, has sickened at least 843 people in 31 states since May 1, according to the latest data from the Centers for Disease Control and Prevention and state health data. Michigan is already battling an outbreak that exceeds the total number of cases in 2025 by more than 14 times, and several other states are reporting cases in the hundreds.
Additional state-level reports show significant spikes in cases that are not yet reflected in the CDC surveillance dashboard, which has previously only been updated monthly. The latest data, released July 9, still lags state reports as authorities work to confirm infections. At this time, there is no single source evidence linking the case clusters.
Here’s what you need to know since the CDC’s last update on June 16, which reflected only 145 cases from 18 states nationwide.
What is cyclosporosis? What are the symptoms?
Cyclosporiasis is a parasitic infection that causes unpleasant gastrointestinal symptoms associated with food poisoning, such as diarrhea, nausea, and vomiting. It is caused by the parasite Cyclospora caietanensis, also known simply as Cyclospora, and is usually transmitted through contaminated food.
Although unpleasant, it is generally not known to cause death, and many cases go unreported because people recover at home without seeking medical attention.
According to the CDC and Cleveland Clinic, the most common symptom is watery, frequent, and sometimes “explosive” diarrhea, but other problems include:
- vomiting
- loss of appetite
- Bloating, including belching and gas, or stomach cramps
- Extreme fatigue (malaise)
- heat
- nausea
View a map of states with cyclosporosis cases
The CDC tracks cystosis cases based on when and where a person was infected. As of July 9, 843 people in 31 states have been infected with the disease since May 1. A further 343 people were infected while traveling abroad and are being tracked and categorized separately.
Of the 843 people who became ill in the United States, 86 were hospitalized. No one died. Cases occurred in people aged 5 to 88 years, with a median age of 44 years. The cyclosporiasis “season,” or month when the U.S. typically sees a spike in the disease, begins May 1 and runs through the end of August, according to the CDC.
However, these numbers do not include hundreds more cases reported by individual states.
Why CDC numbers don’t match state releases
Even with recent updates, the CDC’s numbers still don’t match what each state is reporting individually. For example, the CDC lists only 161 to 300 cases in Michigan as of July 9, but state health officials reported 700 total cases to USA TODAY as of July 6.
The reason is simple. The CDC only reports laboratory-confirmed cases that occurred after May 1 and were “domestically confirmed,” meaning the person who became ill had not traveled internationally in the 14 days prior to developing symptoms. Meanwhile, many individual states are sharing data, including year-to-date numbers of cases and data that does not distinguish between domestic and foreign infections.
“CDC recognizes that states are likely reporting a higher number of cystospermia cases than reflected in CDC data and is working closely with states to update numbers as additional cases are confirmed,” the agency said in a statement at the top of its cystospermia surveillance page. “Since May 1, 2026, CDC has received reports of 843 confirmed cases of cyclosporiasis in the country and is aware of more than 1,500 cases that require further analysis to confirm that the disease is domestically acquired cyclosporiasis.”
In other words, authorities know there are others infected and now they just have to wait for tests to be completed. Additionally, even if states have had hundreds of cases since the beginning of the year, the CDC will not count the number of cases unless it can prove that people were infected after May 1st.
“We assume a six-week reporting lag between onset of symptoms and case reporting to CDC. Therefore, we expect the number of cases to continue to increase as data is received,” the portal page says. Officials told USA TODAY that the number of cases is rising so rapidly that they will begin requesting state data weekly instead of monthly.
States reporting the highest numbers
As of July 6, Michigan had more than 700 infections, making it the state with the highest number of infections to date, but other states are also reporting cases in the hundreds.
The Ohio Department of Health told USA TODAY on July 9 that it had recorded 364 cases of cyclosporiasis, all but six of which occurred after May 1. All cases were locally acquired, and 46 of them were hospitalized.
North Carolina told USA TODAY it had 205 cases between May 1 and July 9, while New York City had recorded 301 total cases as of July 7, 273 of which occurred after May 1. New York City’s case count includes not only people who may have been infected domestically, but also people who have recently traveled abroad.
New York state, which reports and tracks infectious diseases separately from New York City, confirmed 120 cases between May 1 and July 7. It has not been made clear whether all reported cases were infected within the country. The number of infections in the state has been relatively high in the past few years, ranging from 500 to 700 in 2024 and 2025.
How to avoid getting infected with parasites that cause diarrhea
Cyclosporiasis is transmitted through the fecal-oral route, that is, through contact with food, drinks, and surfaces contaminated with infected fecal particles. Usually this means directly consuming affected food or drink, or touching something contaminated and then touching your mouth without washing your hands.
A spike in cyclosporiasis infections is often seen during the warm summer months as infected fecal matter invades fresh summer crops such as basil, raspberries and lettuce, all of which have been linked to past outbreaks in the United States, according to the CDC.
Symptoms usually begin about a week after exposure, but symptoms can appear in as little as two days or up to two weeks later.
The infection is treated with antibiotics, and most healthy people can probably fight it off on their own, but the disease can last for months and come back if untreated, according to the CDC. As is often the case, children, older adults, and people with weakened immune systems are more likely to get seriously ill and even die and should contact a health care professional if they become ill.
To prevent getting cysticercosis in the first place, the CDC, Cleveland Clinic, and Michigan Department of Health recommend the following:
- Avoid consuming food or water that may be contaminated with feces. Avoid drinking or cooking with untreated water.
- Wash your hands with soap and water after using the restroom and before, during, and after preparing food.
- Wash all food preparation surfaces, including utensils, cutting boards, and countertops, before and after use.
- Wash and peel vegetables before eating. Give skinned produce such as melons and cucumbers a good rub. Cut out any damaged or bruised parts of fruits and vegetables before cooking and eating.
- Refrigerate cooked fruits and vegetables as soon as possible (within 2 hours).
