Answering your questions about Cyclosporiasis, the stomach bug outbreak that could linger through summer

Digital Editor

Cyclosporiasis cases are surging across the country, leaving many people wondering what the parasite is and how worried they should be.

Health officials are still working to pinpoint the source, though lettuce and salad greens are among the foods being investigated in some states.

Above video | Dr. Steven Goldberg talks about the parasite behind explosive diarrhea

So, how does cyclospora spread, what symptoms should you watch for and which foods may carry the greatest risk?

Can washing produce keep you safe, and when should you call a doctor?

We’re answering the biggest questions about the illness and what you can do to protect yourself.

What is cyclospora?

Cyclospora is a microscopic, spherical parasite that commonly causes watery diarrhea “with frequent and sometimes explosive bowel movements,” according to the U.S. Centers for Disease Control and Prevention. The illness, called cyclosporiasis, is not usually life-threatening and is typically treated with antibiotics. Outbreaks tend to occur most often in the late spring and summer.

The heat-loving parasite infects the bowels and spreads through feces.

It’s less common than a number of other kinds of foodborne illnesses, including salmonella and E. coli. For years, few U.S. cyclospora outbreaks were reported each year. But the number started rising about a decade ago, with a particularly notable spike in 2018 and 2019. Experts attribute the increases to climate change and better detection.

About 1 in every 11 cases has been hospitalized, according to data reported to CDC. No deaths have been reported.

What’s the current situation?

Thousands of cases have been reported with more than a hundred hospitalizations.

Below is a map of where cases have been reported.

What foods have been linked to cyclospora?

The gut-churning parasite has been found in fresh produce such as:

• Parsley
• Cilantro
• Snow peas
• Mesclun lettuce
• Spinach
• Salad mixes
• Raspberries, blueberries and blackberries

How can you protect yourself from cyclospora?

People who have diarrhea that hasn’t gone away on its own within a few days should see a health provider and discuss the possibility of cyclospora, officials say.

The best way to prevent infection with a parasite is to avoid food or water that may have been contaminated.

Fresh produce should be thoroughly washed before being eaten. But be aware that cyclospora can really stick to some foods, so washing may not eliminate the risk of infection.

As Michigan officials investigate the potential source, they recommend consumers purchase whole heads of lettuce rather than pre-washed, bagged lettuce or salad mixes, and to remove the outer two to three leaves before washing the remaining leaves under running water.

They also say to cook vegetables when possible.

Is anyone more at risk?

Not really. But medical officials say those with compromised immune systems may have a harder time fighting the parasite.

How does this outbreak compare to previous ones in the US?

Comprehensive data on cyclospora outbreaks is lacking. But available information shows only a small number of documented outbreaks in the last 20 years have surpassed 1,000 cases. That short list includes a 1997 outbreak tied to Guatemalan raspberries that sickened more than 1,000 in the U.S. and Canada, and a 2019 outbreak linked to Mexican basil that sickened more than 2,400.

The Associated Press contributed to this report.