Everything You Need to Know About Cyclospora


Dr. Todd Ellerin

Todd Ellerin, MD, Director of Infectious Disease

While outbreaks of foodborne illness in the United States aren’t nearly as common as they used to be, we still see them occur from time to time. Foodborne illness can be caused by dozens of different types of bacteria or parasites, and symptoms can range from mild to severe, depending on the patient.

Many people are familiar with the most common causes of foodborne illness, including viruses like the Norovirus and bacteria like E. coli, Listeria monocytogenes, and Salmonella. Outbreaks of illness related to these pathogens appear in the news every so often, forcing product recalls, store closures, or advisories from local health boards.

Recently, another pathogen began appearing in the news: Cyclospora.

What is Cyclospora?

Cyclospora is the shorthand name for Cyclospora cayetanensis, which is a parasite. This parasite can contaminate food or water; if a human then ingests that food or water, it can lead to illness. The illness caused by Cyclospora is called cyclosporiasis.

Like most of the illnesses caused by the common pathogens mentioned above, cyclosporiasis is a gastrointestinal illness. The most common symptom of cyclosporiasis is diarrhea; other symptoms can include nausea, fatigue, cramping, and flu-like symptoms.

Where does Cyclospora come from?

Fresh produce is usually the cause of cyclosporiasis outbreaks in the United States. According to the CDC, past American outbreaks of cyclosporiasis were caused by raspberries, lettuce, peas, and basil.

In those cases, the affected produce was imported from outside of the country. The produce was contaminated by Cyclospora at some point during the growing or packaging process, and was then sold to American consumers.

Any consumers who ingested that produce without cooking it or washing it thoroughly were exposed to Cyclospora.

Why is Cyclospora in the news?

When the Massachusetts Department of Public Health issues a warning about a foodborne illness, people tend to pay attention!

That’s exactly what happened with Cyclospora, with the Department of Public Health issuing a press release on Monday warning of an increase in the number of cyclosporiasis cases seen in the state.

The increase we’re seeing in Massachusetts coincides with an increase in cases in other states, including Florida, Michigan, New York, and Virginia.  

According to the DPH, Massachusetts has seen more than 100 cases of cyclosporiasis since the beginning of May; to put that in perspective, the DPH reported seeing just a few dozen cyclosporiasis cases over the past three years!

The DPH noted that most of the reports have originated from the greater Boston area, but also mentioned that it has received reports of infections from other parts of the state as well.

The increase in the number of cases around the United States makes it likely that a particular type of produce is the culprit, but state health departments and the CDC have yet to determine the specific source.

How can you avoid Cyclospora?

While the increase in reports of cyclosporiasis may be alarming, you don’t need to take drastic steps to prevent yourself from encountering Cyclospora. Instead, basic food safety rules should be enough to avoid encountering this parasite.

As is the case with most foodborne pathogens, cooking food properly will eliminate any concerns about Cyclospora, but we know you can’t really cook a salad.

Instead, it’s important to wash, wash, wash.

  • Wash your hands with soap and water before and after handling any fresh food.
  • When preparing produce, wash the fruits and vegetables thoroughly before cutting or peeling.
  • Wash your hands in between handling different kinds of foods, like produce and raw meat.
  • The CDC recommends scrubbing the surface of firm fruits and vegetables with a brush, and also recommends removing and discarding any parts of the produce that look bruised or damaged.


What should I do if I think I have cyclosporiasis?

Dozens of different gastrointestinal illnesses can cause symptoms like diarrhea and nausea, so it’s important to contact your primary care provider if you’re experiencing the symptoms discussed above. Normally, we only suspect something like cyclosporiasis if the symptoms have persisted for 7-10 days.

During your visit, your provider can run tests to find the cause of your symptoms. If a case of cyclosporiasis is confirmed, treatment can begin. While it’s possible for healthy individuals to fight off a Cyclospora infection without treatment, the normal recommended treatment for cyclosporiasis is a course of Trimethoprim-sulfa (TMP-SMX), which is an antibiotic. Fluids may be given as well to help replenish those lost from diarrhea.

Also, in cases like this where there are concerns about a potential outbreak, your primary care provider confirming a case of cyclosporiasis can help entities like the DPH and CDC better identify the source of the contamination, preventing further illness.


Todd Ellerin, MD is Director of Infectious Disease at South Shore Health.