Some people infected with the microscopic parasite that causes cyclospora infection develop no signs or symptoms. For others, the main indications of the infection are:

• Watery diarrhea
• Frequent and sometimes explosive bowel movements

If you're otherwise healthy, the diarrhea may end by itself within a few days, or it may become chronic, lasting for weeks. If you have a compromised immune system, such as from HIV or other chronic illness, the infection can last for months if not treated.

For some people, bouts of diarrhea may alternate with bouts of constipation. Signs and symptoms usually begin within two to 11 days of eating contaminated food or drinking contaminated water.

Other signs and symptoms include:

• Loss of appetite
• Weight loss
• Bloating
• Flatulence
• Burping
• Stomach cramps
• Nausea
• Vomiting
• Muscle aches
• Low-grade fever
• Fatigue
• General feeling of unwellness (malaise)

When to see a doctor
There are many possible causes of diarrhea and other gastrointestinal signs and symptoms. If you develop persistent diarrhea that lasts several days or recurs, contact your doctor so that he or she can identify the cause and recommend treatment. If you've eaten a food that's been recalled because of a cyclospora outbreak, be sure to tell your doctor.

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A tiny, one-celled parasite, Cyclospora cayetanensis, causes cyclospora infection. You get it by drinking water or eating food that's been contaminated by an infected person.

No one knows exactly how cyclospora is transmitted. A person infected with cyclospora passes the parasite in stool. However, unlike some other food-borne parasites, cyclospora doesn't become infectious until days or weeks after it's passed in a bowel movement. So it's unlikely that you can get the infection directly from an infected person, such as a restaurant worker who doesn't wash his or her hands adequately after using the toilet.

Before 1996, sporadic cases of cyclospora infection turned up only in people who traveled in developing countries and in those with compromised immune systems, such as from HIV. However, since 1996, imported raspberries, mesclun lettuce and fresh basil have been implicated in cyclospora outbreaks in the United States and Canada.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

In the past, people who traveled in developing countries were more likely to get cyclospora infection. These days, the infection is found worldwide, and anyone who ingests contaminated food or water can get it. However, despite outbreaks around the world, the risk of getting cyclospora infection is still low compared with other intestinal food-borne and waterborne illnesses.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

The prolonged diarrhea of untreated cyclospora infection can cause dehydration. If you're an otherwise healthy adult, you can treat dehydration by drinking more fluids. Some people may need to be hospitalized to receive intravenous fluids because they're at higher risk of severe dehydration. Examples include:

• People with compromised immune systems
• Infants and young children
• Older adults

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

If you have a mild case of cyclospora infection, you may not need to seek medical treatment because it will clear up by itself. However, you may want to call your doctor if the illness lasts more than a few days or if it appears to be causing dehydration.

Warning signs of dehydration include:

• Sunken eyes
• Dry mouth and tongue
• Reduced production of tears
• Decreased urine output

What to expect from your doctor
Your doctor will need to know:

• When the illness began
• The frequency of the vomiting or diarrhea
• Whether the vomit or diarrhea contains bile, mucus or blood
• If you have a fever

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

Because there are so many possible causes of diarrhea and other gastrointestinal symptoms, diagnosis of cyclospora infection requires special laboratory tests to identify the parasite in your stool.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

The only effective treatment is a combination antibiotic known as trimethoprim-sulfamethoxazole (Bactrim, Septra). For people who can't take sulfa, some evidence suggests that ciprofloxacin (Cipro) or nitazoxanide (Alinia) might be effective.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

To prevent or treat mild to moderate fluid loss from the severe diarrhea associated with cyclospora infection, it's generally adequate for healthy adults to drink water. Avoid coffee, tea and other drinks that contain caffeine and alcohol because they can increase dehydration. Fruit juice and soda can make diarrhea worse.

For children and infants, you may want to use an oral rehydration solution, such as Pedialyte. Avoid taking anti-diarrheal medication, because it could interfere with your body's efforts to rid itself of the parasite.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.

When traveling to developing nations, it's essential to be careful about what you eat and drink. However, recent cyclospora infection outbreaks have been linked to foods imported to or grown in the United States and Canada. Even careful washing of these imported foods isn't enough to eliminate the parasite that causes the infection.

To keep track of what foods have been linked to recent outbreaks of cyclospora infection, you may want to periodically check the food safety alert section of the Food and Drug Administration's Web site.

©1998-2009 Mayo Foundation for Medical Education and Research (MFMER). Terms of use.