When your child has been sick for days with vomiting and diarrhea, every parent asks the same question.

Is this just a stomach bug or is something else going on?

This summer that question matters more than usual. A parasite called Cyclospora is circulating nationally with over 1,600 confirmed cases and four already identified right here in Northern Virginia. And because it looks a lot like food poisoning and the typical stomach virus, it keeps getting missed.

Here is a clear breakdown of all three so you know exactly what you are dealing with and when to come in.

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The Stomach Virus

The stomach virus is the most common cause of vomiting and diarrhea in children and what most parents are used to dealing with. The most well known culprit is norovirus, though several other viruses can cause the same symptoms.

What it looks like

Vomiting and diarrhea that comes on suddenly, often accompanied by a low fever, nausea, and stomach cramps. Your child may feel completely fine one hour and then be sick the next. The onset is typically rapid and the first 12 to 24 hours are usually the worst.

How it spreads

This is where the stomach virus stands out from the other two. It spreads easily and quickly from person to person through direct contact, shared surfaces, and contaminated food or water. If one person in the household gets it, others usually follow within a day or two.

How long it lasts

Most stomach viruses resolve within 24 to 72 hours with rest and fluids. Symptoms tend to improve steadily after the first day.

The key tell

Multiple people in the household get sick within a short window. Symptoms come on fast and improve just as fast.

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Food Poisoning

Food poisoning occurs when contaminated food or drink introduces bacteria, viruses, or toxins into the digestive system. Common culprits include Salmonella, E. coli, Staph aureus, and Listeria.

What it looks like

Vomiting, diarrhea, and stomach cramps that come on quickly, usually within a few hours of eating the contaminated food. It can be intense but tends to move through the system relatively fast. Some types of food poisoning also cause fever.

How it spreads

Food poisoning does not spread person to person the way a stomach virus does. It comes from a specific contaminated food source. Others in the household may get sick if they ate the same food, but not from being around the sick person.

How long it lasts

Most cases of food poisoning resolve within 24 to 48 hours. The faster onset and faster resolution is what typically distinguishes it from other causes.

The key tell

Symptoms begin within hours of a specific meal. The timeline from eating to getting sick is usually short and obvious.

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Cyclospora

This is the one making headlines this summer and the one most likely to get missed. Cyclospora cayetanensis is a microscopic parasite, not a virus or bacterium, and it behaves very differently from the other two.

What it looks like

Watery diarrhea that will not quit, loss of appetite, bloating, cramping, fatigue, and sometimes a low fever. Symptoms usually appear about a week after exposure, though anywhere from two days to two weeks is considered normal. This delayed onset is one of the reasons it gets missed.

How it spreads

Cyclospora does not spread from person to person. This is one of its most important distinguishing features. It spreads through contaminated food or water, most often fresh produce like lettuce, herbs, and berries. Past outbreaks have been linked to fresh basil, cilantro, raspberries, and salad greens.

How long it lasts

This is the biggest red flag. Without treatment, Cyclospora can drag on for weeks, often easing up and then coming back. The CDC describes this relapsing pattern as a hallmark of the illness. A child who seems to be getting better and then gets sick again with the same symptoms is a significant warning sign.

With the right antibiotic treatment, trimethoprim-sulfamethoxazole, symptoms resolve relatively quickly.

The key tell

Diarrhea that keeps coming back after seeming to improve. No one else in the household is sick. Your child recently ate fresh produce. Symptoms started gradually about a week after exposure rather than within hours.

One critical thing to know about testing

Standard stool tests do not always detect Cyclospora. It requires specific laboratory testing that is not part of a routine ova and parasite panel. If you suspect Cyclospora based on your child’s symptoms, mention it specifically when you come in. The earlier it is identified and treated, the faster your child recovers.

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Side by Side Comparison

Onset Stomach virus: sudden, within hours Food poisoning: fast, within hours of eating Cyclospora: gradual, about a week after exposure

Duration Stomach virus: 24 to 72 hours Food poisoning: 24 to 48 hours Cyclospora: weeks if untreated, relapsing pattern

Spreads person to person Stomach virus: yes, easily Food poisoning: no Cyclospora: no

Source Stomach virus: contact with infected person or surface Food poisoning: specific contaminated food Cyclospora: contaminated fresh produce

Treatment Stomach virus: rest and fluids, supportive care Food poisoning: rest and fluids, supportive care Cyclospora: specific antibiotic required

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When to Come In

Any of these three conditions can lead to dehydration, which is the most serious complication in children. Come in to Night Watch if your child has any of the following.

We offer on-site evaluation and IV hydration therapy for children who are significantly dehydrated. Walk in anytime. No appointment needed.

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How to Protect Your Family from Cyclospora This Summer

Since Cyclospora is the one circulating right now, here are the prevention steps that matter most.

👉 Wash hands with soap and water. Hand sanitizer does not kill this parasite. Soap and water does. 

👉 Skip pre-washed bagged salad. Buy whole heads of lettuce and wash thoroughly yourself. 

👉 A 3 parts water to 1 part vinegar soak helps lift the parasite off produce. 

👉 Cooking to 158°F kills the parasite outright. A fully cooked meal is lower risk than a raw salad bar.

 👉 For kids who love fresh fruit, frozen fruit in a smoothie is a safer option right now.

This blog post is for educational purposes only and does not constitute medical advice. Please consult with a qualified healthcare provider for personalized guidance regarding your child's health.