An outbreak of diarrhea caused by a parasite has hit at least 1,400 people. Here’s how to stay safe

By Brenda Goodman, CNN

(CNN) — Summer is the best time to be enjoying fresh berries and cool caprese salads with a sprinkling of fresh basil, preferably poolside.

But this summer, with cases of diarrhea caused by a microscopic parasite called cyclospora climbing across several states, you may want to take extra care with how you prepare your produce and where you swim.

The epicenter of an outbreak is Michigan, where more than 1,200 people have fallen ill. Ohio has also seen nearly 200 cases. Other states, including New York, Illinois, Indiana, North Carolina, and Texas have also reported a jump in cases, although it’s not clear whether they’re all part of the same outbreak. More than 40 people have been hospitalized.

While it’s not likely to kill you, cyclosporiasis, by all accounts, is not something you want to deal with. The watery diarrhea, cramping and bloating it causes can quickly leave you dehydrated and even land you in the hospital.

“If you get norovirus or something, you might have a rough 24 or 48 hours, but people with this parasite can be sick for weeks or sometimes even months with a sort of relapsing pattern, and so that can really wear down your body,” said Dr. Caitlin Rivers, an epidemiologist and senior scholar at the Johns Hopkins Center for Health Security. She recently wrote about the outbreak in her “Force of Infection” newsletter.

Importantly, investigators say they haven’t yet been able to determine the source or sources causing this year’s cyclosporiasis cases.

But based on past experience with this bug, there are some ways you can try to keep yourself safe.

Know how it infects people

The good news is that cyclosporiasis doesn’t pass directly from person to person. You get it by eating or drinking something that’s been contaminated several weeks prior, usually fresh produce or water from a swimming pool.

This parasite is resistant to bleach, so it can show up in recreational water sources like chlorinated swimming pools and splash pads, but also in lakes and rivers. If you have an outbreak in your area, especially, it might be best to avoid public swimming areas.

Cook your fruits and veggies

When it comes to fresh fruits and vegetables, the safest thing to do to prevent getting sick is to cook them, Rivers said.

Cooking food to an internal temperature of 158 degrees Fahrenheit or higher kills cyclospora, according to the Michigan Department of Health and Human Services.

How long that takes will depend on your cooking method. Using a food thermometer can help you know that you’ve reached a safe temperature.

Always wash your produce

If it’s something you can’t really cook, like salad greens, you’ll want to wash it thoroughly — for at least a minute — by immersing it in water and swishing gently by hand. The bowl of a salad spinner is effective for this, for example.

Researchers have also tested a rinse of one part vinegar to three parts water, and this also works to remove most cyclospora spores from produce.

In one study, even careful washing couldn’t remove all cyclospora, however, which proved to be stickier than other parasites.

“My read of this study is that rinsing helps, but it’s not reliable,” said Rivers.

Other practices that may help reduce the risk include breaking off and discarding the outer leaves of a head of lettuce, and scrubbing firm fruits and vegetables with a soft brush while rinsing.

Consider steering clear of certain high-risk foods

You don’t have to avoid all raw fruits and vegetables because of an outbreak with an undetermined cause. But if you are particularly vulnerable, perhaps because of age or medications that lower your immune function, you could consider steering clear of foods that have been involved in outbreaks in the past.

They include foods that are harder to wash, or that people might be less diligent about washing, including:

• Raspberries
• Basil
• Salad mixes (including vegetable trays and coleslaw)
• Cilantro
• Berry/fruit mixes
• Lettuce
• Snow peas

What to do if you get sick

In the midst of a known outbreak, infectious disease experts recommend heading to the doctor for a diagnosis and treatment if you have diarrhea for longer than 48 hours.

“If it’s been more than 48 hours, it’s reasonable to test for it,” said Dr. Rebecca Schein, an infectious disease expert at Michigan State University Health Care.

Standard tests to look for stomach bugs don’t typically include cyclospora. Your doctor may need to special order it. Because the parasite sheds intermittently, you may also need several tests spaced 24 hours apart to get an accurate diagnosis.

Treatment is seven to 10 days of the combination antibiotic sulfamethoxazole-trimethoprim, which is sold as Bactrim or Septra.

“The recommendation is to treat people who have cyclosporiasis because it can last so long and it’s just uncomfortable,” Schein said. “And it can increase, you know, spread into the environment if we don’t treat it.”

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