What’s Causing Your Diarrhea — Salmonella, Cyclosporiasis, or Something Else?

If you suddenly come down with a stomach bug, can you even be sure what caused it?

“These foodborne illnesses all involve the gastrointestinal tract, so they can have very similar symptoms,” says William Schaffner, MD, a professor of infectious diseases at Vanderbilt University in Nashville, Tennessee, and a spokesperson for the Infectious Diseases Society of America. “Most people feel miserable for a period of time and recover with supportive care, but specific treatments in more severe cases are different, so knowing which illness you have is important.”

By looking back at what you’ve eaten and identifying specific symptoms, doctors are better equipped to make a probable diagnosis and recommend the best treatment. Definitive diagnosis often requires lab testing, though.

Cyclosporiasis and Salmonella Are Usually Linked to Different Kinds of Foods

Cyclospora (the parasite that causes cyclosporiasis) and salmonella (the bacterium behind salmonellosis) both infect humans through food or water contaminated with human feces. However, they tend to be associated with different kinds of foods.

• Leafy greens and lettuce
• Cabbage
• Basil
• Cilantro
• Parsley
• Broccoli
• Snow peas
• Sugar snap peas
• Raspberries

• Chicken
• Beef
• Turkey
• Seeded vegetables like tomatoes
• Nuts

Contaminated foods can spread germs to other food items if not handled properly. Unwashed hands, chopping boards, and knives can also spread these germs in the kitchen.

Symptoms of Cyclosporiasis and Salmonella Can Overlap

• Diarrhea
• Stomach cramps
• Bloating
• Loss of appetite
• Nausea
• Vomiting
• Tiredness
• Headache

As with any illness that causes diarrhea or vomiting, dehydration is a primary complication and major concern, warns Dr. Schaffner.

“You can obviously lose fluid through vomiting and diarrhea, and we always underestimate the amount of fluid loss,” he says. “Dehydration is especially a risk for the very young and the very old because they’re more fragile, as well as for people with chronic underlying medical conditions such as diabetes. It can make your diabetes control go out of whack.”

When there is less water in your body, there’s less liquid in your bloodstream. This can cause glucose to concentrate more in your blood, leading to high blood sugar levels.

How Do Cyclosporiasis Symptoms Differ From Those of Salmonella Poisoning?

While similar signs of illness make the two hard to distinguish, there are differences.

Symptom Onset

Symptoms of salmonella poisoning can begin six hours to six days after exposure, and they come on fast.

Cyclosporiasis takes time to build up in the body, so symptoms begin later, from two days to two weeks after eating contaminated food.

Duration

Salmonella symptoms tend to last four to seven days, while cyclosporiasis symptoms can continue for weeks or even months.

Recurrence

Salmonella sickness is a one-and-done episode. Cyclosporiasis symptoms can pass and then start up again. “The body has a more successful method in its inflammatory response to get rid of the bacteria than it does the parasite,” says Schaffner. “The Cyclospora parasite is able to hang out in the body for longer periods of time before it is eliminated.”

Type of Diarrhea

Fever and Serious Complications

Both infections are usually not life-threatening, but salmonellosis carries a higher risk of severe complications, says Norman Beatty, MD, an associate professor of infectious diseases and global medicine at the University of Florida College of Medicine in Jacksonville.

“With salmonella infection, you are more likely to have a fever and possibly develop sepsis,” says Dr. Beatty. Sepsis is an extreme immune response to infection that can be fatal without treatment. “Fever and sepsis would be uncommon with cyclosporiasis. It’s really just an organism that disrupts the normal flora [microbial content] of the gastrointestinal system.”

Salmonella Is Contagious, but Cyclosporiasis Is Not

The same is not true for cyclosporiasis. “A human with cyclosporiasis is really noninfectious to another human because the Cyclospora parasites really have to contaminate an environment and mature before becoming infectious,” says Beatty.

Treatments Depend on the Illness

With so much diarrheal illness circulating currently, Schaffner encourages people who get sick to see a healthcare provider soon after symptoms appear.

“If it is cyclosporiasis, you don’t want this recurrent infection that can go on for weeks,” he says. “You want to get the appropriate antibiotic that can treat it.”

For both illnesses, it’s also important to drink lots of fluids, get plenty of rest, and eat fairly bland foods.

Could Something Else Be Causing Your Diarrhea?

Several other foodborne illnesses regularly cause outbreaks in the United States, but because symptoms are similar, it can be challenging to know what specific illness you have unless lab testing is performed.

Other common causes of food poisoning include:

• Norovirus This germ accounts for about 58 percent of food poisoning cases in the United States, but norovirus outbreaks usually happen seasonally in colder months.

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• E. coli These infections cause hundreds of thousands of illnesses every year. These bacteria are the most common cause of “traveler’s diarrhea,” acquired from dirty food or water in regions with poor sanitation, says Beatty.
• Listeria These bacteria can contaminate a variety of foods, says Schaffner. “Listeria is one of those very rare bacteria that can actually multiply at refrigerator temperature,” he says. “Other bacteria go dormant at that temperature, but Listeria can actually grow.”
• Campylobacter These bacteria are a common cause of diarrheal illness worldwide, often associated with undercooked poultry and raw milk.

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How to Lower Your Risk of Food Poisoning

Experts offer the following advice to decrease your risk of salmonella poisoning, cyclosporiasis, and other foodborne illnesses:

• Wash your hands before and after preparing food.
• Wash all fruits and vegetables thoroughly under running water before eating, cutting, and cooking.
• Scrub firm fruits and vegetables, such as melons and cucumbers, with a clean produce brush.
• Cut away any damaged or bruised areas on fruits and vegetables before preparing and eating. Remove outer leaves of lettuce and cabbage.
• Avoid precut and packaged produce. They have undergone more handling and exposure to potential sources of contamination.
• Consider buying locally sourced produce (at a farmer’s market, for example), which is less likely to be contaminated.