What to know about cyclosporiasis, the food parasite making Marylanders sick

A nasty bug that causes severe diarrhea is making its way around the country and Maryland.

There are cases of cyclosporiasis every year, but lately there are much more than usual, and officials aren’t yet sure why.

In Maryland, there have been 32 cases so far this year, with 28 of them since May, according to the Maryland Department of Health. Other states are reporting far more cases, including Michigan, where health officials say there are more than 1,250 cases.

Here’s what you need to know about cases of cyclosporiasis.

What is cyclosporiasis?

The infection is caused by a parasite passed through feces and ingested through contaminated water or food, typically produce.

It was long traced to travel to countries where the microscopic pest is endemic. But U.S. health officials say they have increasingly detected the parasite in both locally grown and imported fruit and vegetables.

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How common is it here?

“There’s always cases, especially in the summer,” said Dr. Miriam Alexander, preventative health physician and medical director for occupational health at LifeBridge Health.

The Maryland Department of Health gathers reports from local health departments, and has confirmed 28 cases between the beginning of May through July 7.

By comparison, there were 18 reported during the same time period in 2025, and 19 during that time in 2024.

Nationally, there are typically about 1,000 cases annually, with the most reported in spring and summer. Maryland had a total of 128 last year, and 204 the year before.

Alexander said cases have been rising in recent years, but that may be in part due to better diagnostic testing methods.

Why are more people getting sick now?

State health officials say they have not identified a common link among the current cases, but investigations are ongoing.

How can you avoid it?

There isn’t a reliable way to avoid the parasite, other than avoiding all fruits and vegetables.

Routine chemical disinfection and sanitization of food and water is unlikely to kill cyclosporiasis, according to the U.S. Centers for Disease Control and Prevention.

Officials say washing produce thoroughly still is a good practice to avoid foodborne illness. But the best bet in this situation may be cooking vegetables to 185 degrees to try and kill the parasite, as most cases have been linked to raw produce.

The CDC say the parasite has been specifically linked to berries, such as raspberries that have lots of crevices for parasites to hide, but no cases so far have been tied to frozen or canned fruits and vegetables.

Lettuces may also be a source, and officials say avoid bagged greens and instead buy whole heads of the greens and peeling away the top layers.

“We should always be careful, especially with vegetables and especially from vegetables that are not grown locally,” said Alexander, adding that people should be mindful about eating at reputable restaurants and shopping from quality grocery stores, along with reviewing any health citations the eatery might have.

And, she said, don’t forget to wash your hands, especially after a bowel movement.

What are the symptoms?

The main symptom is watery, sometimes explosive, diarrhea, which can last days to a month or longer, according to the CDC. Sometimes it goes away and returns one or more times.

Other symptoms include extreme fatigue, loss of appetite, weight loss, increased gas or bloating, fever and cramps, nausea, and vomiting.

Symptoms usually appear about one to 14 days after eating the contaminated food or drinking contaminated water, but Maryland health officials say some people have no symptoms.

What should you do if you think you’ve caught it?

People with symptoms should call their doctors for guidance and to report a possible case.

Most people with healthy immune systems recover without any issues or specific treatment, according to the CDC.

There is no preventive vaccine, but the antibiotic TMP-SMX can be used to help clear an infection.

Also, be sure to rest and drink lots of fluids.