The Parasite in the Salad Bowl: What Cyclospora Means for Pregnancy

A parasite spread by raw berries and greens has now sickened more than 400 people across 18 states — and the standard cure is a drug we handle with care in pregnancy.

A parasite spread by raw berries and greens has now sickened more than 400 people across 18 states — and the standard cure is a drug we handle with care in pregnancy. Here is the bind, and what it means before, during, and after a pregnancy.

Right now, a microscopic parasite is moving through the American produce supply. As of early July 2026, the CDC has tracked more than 400 cases of an illness called cyclosporiasis across 18 states. Michigan alone, which usually sees about 50 cases in an entire year, has reported close to 600 in a matter of weeks. Twenty people have been hospitalized. So far, no one has died.

This illness does not spread the way a stomach flu does. You cannot catch it from a sick coworker. You catch it from food — most often raw berries, basil, cilantro, snow peas, or leafy greens that were grown or rinsed with water contaminated by human waste. Federal investigators have not yet named a single source, and they may never find just one.

For most healthy adults, this is a miserable week or two and then it is over. For a woman who is trying to conceive, is pregnant, or has just delivered, the calculation is different. Let me explain why.

What Cyclospora actually is

Cyclospora cayetanensis is a single-celled parasite too small to see. It settles in the small intestine and causes watery, often explosive diarrhea, along with cramping, nausea, low appetite, fatigue, and sometimes a low fever. The tiredness can outlast the diarrhea by weeks.

Two features make it stubborn. First, it is not infectious the moment it lands on a strawberry. It needs days to weeks in the environment to mature. That is why one person almost never passes it to another, and why an outbreak can smolder for weeks before anyone connects the dots. Second, it shrugs off the chlorine washes used on commercial produce. Rinsing your berries at home helps a little, but it does not reliably remove the parasite once it is there. And a routine stool test will miss it — the lab has to be told to look for it specifically.

Untreated, the illness can last a few days or drag on for more than a month, fading and then coming back. The treatment of choice is a common antibiotic combination: trimethoprim-sulfamethoxazole, sold as Bactrim, Septra, or Cotrim. One double-strength tablet twice a day for seven to ten days usually clears it. If you are allergic to sulfa drugs, there is no good backup. That single fact is the root of the problem for pregnancy.

How to lower your risk

Start with the honest part: you cannot fully wash this away.

Cyclospora clings to the crevices of berries and herbs, and it shrugs off the chlorine rinses used on commercial produce.

So the single most repeated tip — rinse your fruits and vegetables under running water — helps a little, but it is not a shield. If the parasite arrived on the food before it reached your kitchen, washing will not reliably remove it.

What does work is heat. Cooking reliably kills Cyclospora. The catch is that the foods most often blamed — raspberries and other berries, basil, cilantro, parsley, snow peas, mesclun and other mixed greens — are the ones we almost always eat raw. That is the whole problem in one sentence.

So this summer, the practical move is to think in tiers.

Cooked produce is safe.

Raw produce you peel yourself, like a banana or an orange, is low risk.

The higher-risk items are the raw berries, fresh herbs, and pre-packaged salad greens tied to past outbreaks. You do not have to swear them off, but during an active surge it is reasonable to cook them, buy them from a source you trust, or simply eat fewer of them for a few weeks.

The rest is basic kitchen hygiene that reduces many foodborne illnesses at once: wash your hands with soap before and after handling food, and clean cutting boards, counters, and knives so raw ingredients do not contaminate ready-to-eat ones. Watch for recalls and public health alerts, and if a specific food is named, throw it out rather than washing it and hoping.

One reassurance: because the parasite has to spend days maturing in the environment before it can infect anyone, you cannot catch it from a sick family member. It comes from the food, not the person.

Preconception

Here is the trap. A woman who is trying to conceive gets sick in, say, the third week of her cycle. She does not yet know she is pregnant. The drug that cures her, trimethoprim-sulfamethoxazole, blocks folic acid — the very vitamin we spend years telling women to take before conception to prevent neural tube defects like spina bifida. The neural tube closes about 28 days after the last period, often before a woman has even missed one. Giving a folate-blocking antibiotic during exactly that window is the last thing we want to do.

This does not mean a woman planning a pregnancy should panic over a salad. It means that if she gets a prolonged diarrheal illness this summer, she should tell whoever treats her that she could be pregnant, so the drug choice is made with eyes open. Staying on her folic acid supplement matters more now, not less.

Pregnancy

For a pregnant woman, the parasite itself is not the main danger. Cyclospora lives in the gut. It is not known to cross the placenta or infect the baby directly, the way some other parasites do. The real threats are indirect, and they are serious.

The first is dehydration. Days or weeks of heavy diarrhea drain fluid and salts. In pregnancy, low fluid volume can reduce blood flow to the placenta and can set off early contractions. A well woman can ride out a stomach bug on the couch. A pregnant woman losing fluid for a month is a different situation, and one that can land her in a hospital on IV fluids.

The second is the treatment bind. In the first trimester, we avoid trimethoprim-sulfamethoxazole when we can, because of the folate-blocking risk to the developing brain and spine and reported links to heart defects. Near the end of pregnancy, the sulfa half of the drug raises a separate concern: it can displace bilirubin in the newborn and raise the risk of jaundice and, rarely, brain injury from it. So the one reliable cure sits in a yellow zone at both ends of pregnancy. This is a genuine judgment call — weighing a prolonged, draining illness against a drug we would rather not use. It is not a decision to make from a website. It belongs in a conversation between a woman and her obstetrician.

Postpartum

A new mother is already running on empty — sleep-deprived, healing, often breastfeeding. A month of explosive diarrhea on top of that is not a minor inconvenience. Dehydration can cut into milk supply at the very moment supply is being established.

The good news is that treatment is usually simpler here. Trimethoprim-sulfamethoxazole is generally considered compatible with breastfeeding a healthy, full-term baby once the newborn period has passed. The exceptions matter: it should be avoided while nursing a premature, jaundiced, ill, or stressed infant, or one with G6PD deficiency, because of that same bilirubin concern. For most healthy nursing pairs a few weeks out, the mother can be treated and keep breastfeeding.

Conclusion

The headlines are about salad, and they should be. Wash your produce, understand that washing is not a force field, and pay attention to recalls. But the story underneath the story is about a specific vulnerability. The disease is usually mild. The cure is usually easy. The problem is that “usually” does not describe the woman who is newly pregnant, or trying to be, or just delivered. For her, both the illness and its treatment carry a cost, and the right move depends on exactly where she stands in that arc.

If you are pregnant or planning to be and you develop diarrhea this summer that will not quit, do not wait it out in silence. Get tested — and make sure whoever treats you knows your reproductive status before the prescription is written. The parasite is small. The decision is not.

Bottom line: a mild parasite turns into a real clinical problem the moment pregnancy enters the picture, because the standard cure is a drug we handle with care in pregnancy. If this kind of plain, honest analysis is useful to you, subscribe to ObGyn Intelligence. The evidence should travel.

References

1. Centers for Disease Control and Prevention. Clinical Care of Cyclosporiasis. Atlanta: CDC; 2024. Available from: https://www.cdc.gov/cyclosporiasis/hcp/clinical-care/index.html

2. Centers for Disease Control and Prevention. About Cyclosporiasis. Atlanta: CDC; 2024. Available from: https://www.cdc.gov/cyclosporiasis/about/index.html

3. Centers for Disease Control and Prevention. Domestically Acquired Cyclosporiasis Surveillance, 2026. Atlanta: CDC; 2026. Available from: https://www.cdc.gov/cyclosporiasis/outbreaks/ [case counts as of early July 2026; state totals per Michigan Department of Health and Human Services].