Here’s what to know about the diarrhea-causing disease before your next trip to the supermarket

Summer salads are meant to be fruity, refreshing and part of a healthful diet. Unfortunately, they’ve also recently developed a bad reputation as cases of the diarrhea-causing intestinal illness cyclosporiasis have risen nationwide and across New York City. 

The disease, perhaps best known for causing explosive diarrhea that can last for weeks, has been linked to contaminated water and produce in the past. The current outbreak has largely affected residents in Michigan and New York state. It is associated with consuming food containing traces of feces infected with Cyclospora. The parasite can also cause bloating, stomach cramps, nausea, vomiting, fatigue, loss of appetite and a low-grade fever. 

The most recent data the New York City Health Department reported was 374 cases since May 1. While cyclosporiasis cases tend to rise in spring and summer, the case count is about three times higher than the same period last year. 

Hand washing for the win

City officials are reminding the public to practice basic hygiene, such as washing your hands, especially before handling food and after using the bathroom or changing diapers. While cyclosporiasis does not spread directly from person to person, hand hygiene can still protect your loved ones. After all, if you end up having rotavirus or another gastrointestinal illness, those do pass person to person. 

“I don’t want someone to think, ‘Great, come over and you won’t get sick from me,’” said Dr. Sharon Nachman, the division chief for pediatric infectious disease at Stony Brook Children’s Hospital. “Good hand hygiene is good for whatever pathogen you have.”

How to have your veggies and clean up well

Experts say New Yorkers shouldn’t skip salads because of concerns about cyclosporiasis. 

“We want you to continue to enjoy your fruits and vegetables,” Nachman said. “Fresh vegetables are much better than any processed food out there.”

City officials recommend rinsing produce thoroughly under running water. Peeling the outer skins of vegetables, according to guidance from New York Presbyterian, also helps. Other experts, including Nachman and the chief of gastroenterology at Northwell Plainview Hospital, have also recommended soaking produce in diluted vinegar. 

It is important to note that  water and cleaning agents such as vinegar and baking soda are not known to kill the parasite on produce. Because cyclospora has a protective outer shell, common sanitizers are unlikely to penetrate it. The only known way to kill cyclospora is to heat the contaminated food or water to 158 degrees Fahrenheit (70 degrees Celsius) or higher.

However, those cleaning methods may help remove some of the parasite from produce. A widely cited 2021 study found that washing berries in vinegar removed more parasites, including cyclospora, than rinsing them under running water. Using a salad spinner after rinsing the berries was also more effective than rinsing alone, though less effective than washing with vinegar. The study’s authors said it was unclear whether the improvement came from the vinegar itself or from swishing the berries in a bowl during washing. They noted that acids may reduce bacteria on berry surfaces that help parasites adhere.

Food safety practices such as washing knives, other utensils and cutting boards while preparing vegetables are just as important, Nachman said. The same advice applies to preparing meat, not just produce. “Just be smart about what you’re doing,” she said. “Take an extra minute, take that step and practice good hygiene.”

Produce to avoid 

City health officials say investigations of the current outbreak are ongoing. Meanwhile, they recommend the following precautions, particularly during summer travel and increased outdoors activity:  

• Avoid drinking water directly from streams, lakes, springs or swimming pools. 
• Avoid raw fruits and vegetables, unboiled tap water, ice and food from street vendors when traveling to countries with poor water treatment or food sanitation

Closer to home, as seasonal farm stands open around the city, there is no evidence that getting fresh produce there or at farmers markets is inherently better or worse than buying produce from a supermarket. 

Produce from local farms may be more traceable, but it is not guaranteed to be free of cyclospora, according to Dr. Adam C. Zimilover, an assistant hospital epidemiologist and infectious disease specialist at Montefiore Medical Center. Contamination, he added, could occur through irrigation, washing, handling or sanitation problems at various points in the growing process. 

“So I wouldn’t say that farm stands are automatically safer or riskier, especially in this

case where we don’t know the specific source of the parasite,” Zimilover said. 

What produce should New Yorkers be most cautious about? On Monday, Michigan officials announced that data points to lettuce or salad greens as a potential source for this outbreak. Still, they said other food items can’t be entirely ruled out, as no specific produce type, grower or supplier has been identified as the source. 

Past cyclosporiasis outbreaks in the U.S. have been linked to raspberries, basil, cilantro, snow peas, leafy greens, lettuce and bagged salad mixes. 

Some infectious disease experts have recommended people with compromised immune systems consider avoiding fresh lettuce and other high-risk fresh produce right now that are harder to clean. That means sticking to fruits with thicker peels that can be removed and cooking leafy vegetables.

What are the symptoms

In most people who are otherwise healthy, symptoms of cyclosporiasis can range from having no symptoms to mild symptoms that resolve on their own, according to Zimilover. 

“We get much more concerned in immunocompromised and elderly individuals,” he said, “who are more likely to have more severe symptoms that are prolonged, then they get worse, then get better, and then get worse again.”

Experts are not yet sure why, but cyclosporiasis differs from norovirus, E. coli and other common gastrointestinal infections, which typically have shorter incubation periods.

The general guidance for people with mild symptoms of cyclosporiasis is to rest and drink plenty of fluids. But when people’s symptoms progress and they are unable to eat or drink, that could lead to dehydration, which would be a “serious concern,” Zimilover said.

Anyone with persistent watery diarrhea and significant fatigue, dehydration or weight loss should seek medical care and tell their doctor, infectious disease experts say. Depending on their symptoms, they may get tested for cyclosporiasis, which is done through a stool sample. Even for people with healthy immune systems, treatment can reduce the length of time they are sick, according to health officials. If they meet the criteria, the recommended medicine for treatment is a combination antibiotic called trimethoprim-sulfamethoxazole. 

“Before we start giving antibiotics indiscriminately, we want to know what’s the pathogen, what’s the story, how often you’re sick,” Nachman said. “If you’re in the hospital and you’re having, for instance, 10 loose stools, and we can’t control it, that may be someone who does it.”

She recommends writing down your symptoms when you go to your physician. Nachman says her patients often forget what symptoms they experienced three days ago, so you should bring your notes with you so you can give them an accurate story of what’s going on, including the following: 

• Where have you been? 
• How long were you there? 
• What did you eat? 
• What are your symptoms now?

“It may be that you drank contaminated water from an overseas place, or you went to a big country fair and got Shigella there from contaminated water,” Nachman said, referencing a bacteria that causes an intestinal infection called shigellosis. “There are so many different pathogens. Giving half a story means you won’t get the whole picture.”