Cyclospora: The Parasite Behind the “Explosive Diarrhea” Outbreak — Symptoms and When to Get Care

Key Takeaways

1. Cyclospora is a microscopic parasite that causes cyclosporiasis — an intestinal illness whose hallmark is frequent, watery, sometimes “explosive” diarrhea.
2. What sets cyclospora apart from ordinary food poisoning is its persistence: without treatment, symptoms can come and go for weeks. It spreads through contaminated food or water — often fresh produce — not from person to person.
3. Cyclosporiasis is treatable with specific antibiotics, and testing requires a provider to order it specifically. If you have prolonged watery diarrhea, especially with loss of appetite and fatigue, getting tested and treated matters — and staying hydrated is essential.

Table of Contents

1. What’s Happening: The 2026 Cyclospora Outbreak
2. What Is Cyclospora?
3. Cyclospora Symptoms to Watch For
4. How Cyclospora Is Different From Regular Food Poisoning
5. How You Get Cyclospora
6. Is Cyclospora Contagious?
7. How to Protect Your Family
8. Produce Safety: What Actually Works
9. How Cyclospora Is Diagnosed and Treated
10. When to See a Doctor
11. Who’s at Higher Risk
12. Frequently Asked Questions
13. Get Tested and Treated in Bloomfield and Cresskill

If you’ve seen the headlines about a parasite causing “explosive diarrhea” across the country, you’re not imagining the alarm — 2026 has brought an unusually large outbreak of a foodborne illness called cyclosporiasis, caused by a microscopic parasite named Cyclospora. Case numbers have climbed far above what’s typical for this time of year, and public health officials are urging people to take some straightforward precautions.

Here’s the reassuring context: while cyclospora causes genuinely miserable symptoms, it’s rarely life-threatening, it doesn’t spread from person to person, and it’s treatable. The illness is worth understanding not because it’s dangerous for most people, but because it’s persistent — left untreated, it can drag on for weeks, and it’s easy to mistake for ordinary food poisoning and just wait out, which isn’t the best approach.

This guide covers what cyclospora is, the symptoms that distinguish it, how to protect your family when preparing fresh produce, and — most importantly — when to get tested and treated. Because the illness requires a specific test and a specific treatment, knowing when to see a provider is the key takeaway. If you’re in New Jersey and dealing with prolonged watery diarrhea, we’ll cover exactly when walking in for care makes sense.

What’s Happening: The 2026 Cyclospora Outbreak

A quick snapshot of the situation, with the important caveat that it’s actively evolving.

The Current Picture

As of mid-July 2026, the CDC has reported well over a thousand confirmed cases of cyclosporiasis across more than 30 states since May 1, with thousands of additional probable cases under investigation — substantially higher than the case count at the same point last year. A number of people have been hospitalized, though no deaths have been reported. The hardest-hit areas have included parts of the Midwest and Northeast.

The Source Is Still Being Investigated

As of this writing, health officials have not identified the specific food source driving the outbreak. Cyclospora investigations are notoriously difficult and slow, because the gap between infection and illness can be up to two weeks, making it hard for sick people to recall exactly what they ate. Investigators trace back common foods among those infected, but confirming a source can take weeks. Historically, cyclospora outbreaks have been linked to fresh produce like herbs and leafy greens.

A Note on These Numbers

Because this is an active, fast-moving situation, the case counts here will change — likely rise — after this is published. For the latest figures and any identified food sources or recalls, the CDC’s cyclosporiasis page is the authoritative, continuously updated source. The practical guidance in the rest of this article — symptoms, prevention, and when to get care — stays useful regardless of the day’s numbers.

What Is Cyclospora?

Cyclospora is a parasite so small you can’t see it, but its effects are unmistakable.

The Basics

Cyclosporiasis is an intestinal illness caused by the microscopic parasite Cyclospora cayetanensis. When someone consumes food or water contaminated with the parasite, it infects the small intestine and causes the characteristic watery diarrhea and other digestive symptoms. It’s a one-celled organism, far too small to see or taste on food, which is part of what makes it tricky to avoid.

Why It’s Seasonal

In the United States, cyclospora infections rise predictably in the warmer months. The CDC considers May 1 through August 31 the annual cyclosporiasis season, since cases cluster in spring and summer. This year’s outbreak fits that seasonal pattern but at an unusually high volume. That’s why produce safety gets extra attention during the summer months specifically.

It’s Not New

Cyclospora outbreaks aren’t a novel phenomenon. There have been notable outbreaks in past years linked to various fresh produce items. What’s different in 2026 is the scale — the number of cases is well above the typical seasonal level, which is why it’s generating national attention.

Cyclospora Symptoms to Watch For

Recognizing the symptoms — and especially their pattern over time — is what helps you tell cyclospora apart from a passing stomach bug.

The Main Symptoms

According to the CDC, the most common symptoms of cyclosporiasis include:

• Watery diarrhea, often frequent and sometimes described as “explosive” — the hallmark symptom
• Loss of appetite
• Weight loss
• Bloating and increased gas
• Stomach cramps
• Nausea
• Fatigue

Less commonly, people experience a low-grade fever and vomiting.

The Timing

Symptoms typically begin about a week after exposure, though onset can range anywhere from 2 to 14 days. This long and variable incubation period is part of why the illness is hard to trace — by the time you’re sick, the meal that caused it may be a distant memory.

The Telltale Pattern: It Comes and Goes

Here’s the feature that most distinguishes cyclospora: without treatment, the symptoms can follow a remitting-relapsing course, meaning they improve and then return, potentially lasting from a few days to a month or more. If you’ve had watery diarrhea that seemed to get better, then came roaring back, and this has stretched on far longer than a typical stomach bug, cyclospora is worth considering. That persistence is the biggest clue.

How Cyclospora Is Different From Regular Food Poisoning

This is a crucial distinction, because cyclospora is easy to mistake for common food poisoning — but the two behave differently and need different approaches.

The Key Differences

• Duration: Ordinary food poisoning usually resolves within a few days. Cyclospora can persist for weeks and relapse.
• The relapsing pattern: Most food poisoning steadily improves. Cyclospora characteristically comes and goes.
• Treatment: Much food poisoning resolves on its own without specific treatment. Cyclospora typically requires specific antibiotics to clear.
• Testing: Standard stool tests may not catch cyclospora unless it’s specifically requested — a provider has to order the right test.

Why This Matters

If you assume prolonged diarrhea is just a bad case of food poisoning and try to wait it out, you could be sick for weeks with a treatable infection. The relapsing, weeks-long nature of cyclospora is exactly why it’s worth getting evaluated rather than toughing out. Our guide on telling food poisoning from a stomach bug covers the more common causes of these symptoms — but when diarrhea drags on unusually long, cyclospora enters the picture.

The Overlap

To be clear, the early symptoms overlap heavily — watery diarrhea, cramps, nausea, and appetite loss look similar at first. You can’t distinguish them by symptoms alone in the first day or two. The distinguishing features are duration and the relapsing pattern, which is why persistent symptoms deserve testing.

How You Get Cyclospora

Understanding transmission helps you protect yourself and explains why produce safety is the focus.

The Fecal-Oral Route

Cyclospora spreads when someone consumes food or water contaminated with feces containing the parasite — the “fecal-oral route.” This typically happens when produce is grown, harvested, or washed using contaminated water, or handled by someone carrying the parasite without proper hygiene. The contamination happens before the food reaches you, which is why it’s so hard for consumers to detect.

Commonly Linked Foods

Historically, cyclospora outbreaks in the U.S. have been linked to fresh produce that’s typically eaten raw, including:

• Leafy greens and lettuce
• Fresh herbs like cilantro and basil
• Raspberries and other berries
• Snow peas and sugar snap peas

Because these foods are usually eaten uncooked, the parasite isn’t destroyed by heat before consumption. Note that in the current outbreak, no specific source has been confirmed — these are the foods linked to past outbreaks.

Contaminated Water

Cyclospora can also spread through contaminated water, whether from drinking untreated water or when such water contacts food during growing or preparation. This is why drinking treated water is part of the standard prevention advice.

Is Cyclospora Contagious?

This is one of the most reassuring facts about cyclospora, and an important one for families.

Not Spread Person to Person

The CDC is clear on this point: cyclosporiasis is not usually spread directly from person to person. Unlike a norovirus stomach bug that rips through a household, you can’t catch cyclospora from a sick family member through normal contact. This is because the parasite needs time — days to weeks — outside the body to become infectious after it’s shed, so it isn’t immediately transmissible the way contagious viruses are.

What This Means for Households

If one person in your home has cyclospora, the others aren’t at risk from being around them the way they would be with a contagious stomach virus. The concern is shared exposure — if the whole family ate the same contaminated produce, multiple people might get sick from that common source, not from each other.

Still Practice Good Hygiene

While person-to-person spread is unlikely, good hand hygiene remains important, especially for anyone handling and preparing food for others. Basic food-safety hygiene protects against cyclospora and a whole range of other foodborne illnesses.

How to Protect Your Family

Since the source of the current outbreak isn’t confirmed, the best protection is general produce and food safety. Here are the steps public health officials recommend.

Core Prevention Steps

• Wash all fresh produce thoroughly under running water before eating, cutting, or cooking
• Wash your hands with soap and water before and after handling or preparing food
• Drink treated or properly sourced water
• Scrub firm produce like melons and cucumbers with a clean produce brush
• Cut away any damaged or bruised areas on fruits and vegetables
• Wash and sanitize cutting boards, utensils, and surfaces before and after preparing produce
• Refrigerate perishable produce promptly

An Important Caveat About Washing

Here’s something many people don’t realize: washing produce reduces cyclospora but may not fully eliminate it, because the parasite can stick tightly to surfaces. Washing is still absolutely worth doing — it lowers your risk and removes other contaminants — but it’s not a guarantee against cyclospora specifically. That’s why the other measures, especially cooking when possible, matter too.

Cooking Kills It

One reliable way to eliminate cyclospora is heat. Cooking produce to 158°F (70°C) or higher kills the parasite. Obviously you won’t cook everything, but for produce you’re able to cook, heat provides certainty that washing alone can’t. During an active outbreak, some people choose to cook more of their vegetables as an extra precaution.

Produce Safety: What Actually Works

Building on the basics, here’s some nuance on produce safety during an outbreak — including guidance that’s come out of the 2026 investigation.

Whole Heads vs. Bagged

Public health guidance during this outbreak has suggested buying whole heads of lettuce rather than pre-washed bagged lettuce or pre-mixed salad kits. The reason: “pre-washed” doesn’t guarantee the produce is free of cyclospora, and re-washing bagged lettuce is unlikely to remove the parasite. Whole produce you wash yourself gives you more control.

The Realistic Approach

None of this means you should stop eating vegetables — fresh produce is important for your health, and the overall risk to any individual remains relatively low. The sensible approach during an outbreak is:

• Wash everything thoroughly under running water
• Cook produce when you reasonably can
• Favor whole produce you prepare yourself over pre-cut and pre-washed
• Stay informed about any specific recalls or identified sources

Watch for Recalls

Because the outbreak source may eventually be identified, keep an eye on public health advisories and recalls. If a specific product gets named, follow the guidance to avoid or discard it. The FDA tracks produce-related cyclospora safety and is a good source alongside the CDC for any developments.

How Cyclospora Is Diagnosed and Treated

The good news: cyclospora is both diagnosable and treatable — but both require seeing a provider.

Diagnosis Requires a Specific Test

Cyclospora isn’t caught by every routine stool test. A provider has to specifically request testing for Cyclospora when it’s suspected, often based on your symptoms (especially prolonged or relapsing diarrhea) and any known exposure or outbreak context. This is a key reason to mention it if you’ve had persistent diarrhea during an outbreak — it prompts the right test.

The Treatment

Cyclosporiasis is treated with a specific antibiotic. The standard treatment is trimethoprim-sulfamethoxazole (TMP-SMX), commonly known by brand names like Bactrim. For people allergic to sulfa drugs, providers can discuss alternatives, though options are more limited. Treatment is generally recommended for most people because the illness can be so prolonged without it.

Hydration Is Essential

Alongside antibiotics, managing the effects of the diarrhea matters:

• Drink plenty of fluids to replace what’s lost
• Use oral rehydration solutions for significant fluid loss
• Rest while recovering
• Seek care for signs of dehydration, which is the main complication

Because prolonged diarrhea can cause significant dehydration, staying ahead of fluid loss is important. For severe dehydration, IV fluids may be needed — our guide on when dehydration becomes an emergency covers the warning signs.

When to See a Doctor

Knowing when to get evaluated is the most practical takeaway of this whole guide.

Get Tested and Treated If You Have:

• Watery diarrhea lasting more than a few days, especially if it’s frequent
• Diarrhea that improved and then came back (the relapsing pattern)
• Diarrhea with significant loss of appetite, weight loss, and fatigue
• Symptoms during a known cyclospora outbreak
• Prolonged digestive symptoms you’d otherwise be tempted to wait out

Because cyclospora needs specific testing and treatment, these situations warrant a visit rather than waiting it out.

Seek Care Promptly for Signs of Dehydration:

• Excessive thirst and dry mouth
• Reduced urination or dark urine
• Dizziness or lightheadedness
• Weakness and fatigue
• In children: no wet diapers, no tears, sunken eyes, unusual lethargy

Dehydration is the main risk with any prolonged diarrheal illness, and it’s very treatable when addressed promptly.

Where to Go

For testing and treatment, walk-in urgent care is a practical option. At A+ Urgent Care, providers can evaluate your symptoms, arrange appropriate stool testing, prescribe the right treatment, and manage dehydration — including IV fluids when needed. Both the Bloomfield and Cresskill locations are open seven days a week, and you can reach them through the contact page. For severe symptoms — signs of serious dehydration, high fever, or bloody diarrhea — seek care promptly.

Who’s at Higher Risk

Cyclospora can affect anyone, but some people are more vulnerable to complications and should be especially cautious.

Higher-Risk Groups

• Older adults, who are more prone to dehydration and complications
• Young children, who can become dehydrated quickly
• People with weakened immune systems, who may experience more severe or prolonged illness
• Pregnant women, who should consult a provider about symptoms and treatment

Extra Caution for These Groups

For higher-risk individuals, it’s worth being more proactive — seeking testing and treatment sooner rather than later, and being especially attentive to hydration. What might be a manageable illness for a healthy adult can hit these groups harder.

Everyone Benefits From Prevention

Regardless of risk level, the produce-safety and hygiene steps in this guide protect everyone. During an active outbreak, they’re worth the small extra effort for every member of the household.

Frequently Asked Questions

What is cyclospora?

Cyclospora (Cyclospora cayetanensis) is a microscopic parasite that causes cyclosporiasis, an intestinal illness. People get infected by consuming food or water contaminated with the parasite. It’s too small to see or taste, infects the small intestine, and causes watery diarrhea and other digestive symptoms. It’s most common in spring and summer and is often linked to fresh produce.

What are the symptoms of cyclosporiasis?

The main symptom is frequent, watery, sometimes “explosive” diarrhea. Other common symptoms include loss of appetite, weight loss, bloating, gas, stomach cramps, nausea, and fatigue. Some people have a low-grade fever or vomiting. Symptoms usually begin about a week after exposure and, without treatment, can come and go for weeks.

How is cyclospora different from food poisoning?

Early symptoms overlap, but cyclospora is distinguished by its duration and pattern. Ordinary food poisoning usually resolves within days, while cyclospora can persist for weeks and characteristically improves then relapses. Cyclospora also requires specific antibiotic treatment and a specifically requested stool test, whereas much food poisoning resolves on its own.

How do you get cyclospora?

You get cyclospora by consuming food or water contaminated with the parasite through the fecal-oral route — often fresh produce grown, harvested, or washed with contaminated water. Historically linked foods include leafy greens, cilantro, basil, raspberries, and snow peas. Because these are usually eaten raw, the parasite isn’t killed by cooking before eating.

Is cyclospora contagious?

No, not directly from person to person. The parasite needs days to weeks outside the body to become infectious after being shed, so you can’t catch it from a sick person through normal contact. If multiple household members get sick, it’s usually from shared contaminated food, not from each other. Good hand hygiene during food prep is still important.

How do I wash produce to prevent cyclospora?

Wash all fresh produce thoroughly under running water before eating or preparing it, scrub firm produce with a clean brush, and cut away damaged areas. Importantly, washing reduces but may not fully eliminate cyclospora, since it sticks tightly to surfaces. Cooking produce to 158°F kills the parasite, and buying whole heads rather than pre-washed bagged produce gives you more control.

How long does cyclospora last?

Without treatment, cyclosporiasis can last from a few days to a month or more, often following a pattern of improving and then relapsing. With the correct antibiotic treatment, symptoms typically resolve more quickly and reliably. This prolonged, relapsing nature is a key reason to get tested and treated rather than waiting it out.

How is cyclospora treated?

Cyclosporiasis is treated with a specific antibiotic — trimethoprim-sulfamethoxazole (TMP-SMX), known by brand names like Bactrim. Treatment is generally recommended because the illness can be so prolonged otherwise. Alongside antibiotics, drinking plenty of fluids to prevent dehydration is essential, and severe dehydration may require IV fluids.

Can washing produce completely remove cyclospora?

Not entirely. Washing under running water reduces the parasite and is definitely worth doing, but it may not fully remove cyclospora because the parasite adheres tightly to produce surfaces. This is why additional measures — cooking when possible, choosing whole over pre-washed produce, and staying alert to recalls — add extra protection during an outbreak.

Should I stop eating salads and fresh produce during the outbreak?

You don’t need to stop eating produce, which is important for your health, and the individual risk remains relatively low. Instead, take precautions: wash thoroughly, cook produce when you can, favor whole produce you prepare yourself over pre-washed bagged items, and follow any specific recalls or public health advisories as the investigation develops.

When should I see a doctor for diarrhea during the outbreak?

See a provider if you have watery diarrhea lasting more than a few days, diarrhea that improved and came back, or diarrhea with significant appetite loss, weight loss, and fatigue — especially during a known outbreak. Because cyclospora needs specific testing and treatment, these situations warrant evaluation. Also seek care promptly for signs of dehydration.

Where can I get tested and treated for cyclospora in NJ?

A+ Urgent Care provides walk-in evaluation for prolonged diarrheal illness at both Bloomfield (Essex County) and Cresskill (Cresskill County) locations, seven days a week. Providers can assess your symptoms, arrange appropriate stool testing, prescribe treatment, and manage dehydration with IV fluids if needed. For persistent or relapsing diarrhea, walking in for evaluation gets you the right test and treatment.

Get Tested and Treated in Bloomfield and Cresskill

The 2026 cyclospora outbreak is a good reminder that not all diarrhea is the same — and that some cases, especially the ones that drag on for weeks or keep coming back, deserve a closer look. Cyclospora is genuinely miserable, but it’s also treatable, and the sooner it’s diagnosed, the sooner the right antibiotic can clear it. The everyday prevention steps — washing produce, cooking when you can, good hand hygiene — protect against cyclospora and a whole host of other foodborne illnesses.

If you’ve had persistent watery diarrhea, particularly the kind that improves and then relapses, and especially during this outbreak, don’t just wait it out. Walk in for evaluation, get the right test ordered, and if it’s cyclospora, start the treatment that actually resolves it. And whatever the cause, if diarrhea is leaving you dehydrated, getting fluids and care promptly will help you recover faster.

About A+ Urgent Care

A+ Urgent Care provides walk-in medical care for families across Essex and Bergen counties, with locations in Bloomfield and Cresskill open seven days a week, including evenings and weekends.

From stomach illnesses and dehydration to infections and injuries, the team provides same-day evaluation and treatment — including stool testing and on-site IV fluids — through a full range of services.

Led by Dr. Ajay Jetley, a board-certified emergency medicine physician with more than 15 years of experience, A+ Urgent Care gets patients diagnosed, treated, and on the mend quickly. No appointment necessary; walk in during operating hours, and for any medical emergency, call 911.