Cyclosporiasis: Cyclospora Infection Signs and Treatment

Author: Thomas C. Weiss
Published: 20 Sep 2013 - Updated: 16 Aug 2026
Publication Type: Informative

Table of Contents:
Synopsis - Definition - Overview - FAQs - Insights, Updates - Related Content

Synopsis

This information explains cyclosporiasis, an intestinal infection caused by the single celled parasite Cyclospora cayetanensis, which people acquire by swallowing food or water contaminated with the organism rather than by direct contact with an infected person. Anyone can be infected, at any age, and while cases are more common in tropical regions and during spring and summer, infections are reported year round in the United States and Canada, with reinfection possible. The typical illness involves watery and sometimes explosive diarrhea averaging six to seven stools a day, along with nausea, bloating, cramps, gas, appetite and weight loss, fatigue, muscle aches and low grade fever, and some people have flu like symptoms first or no symptoms at all. Symptoms usually begin about a week after exposure, and untreated illness can persist from several days to a month or longer and may relapse. Because Cyclospora is not detected by routine stool testing, the page notes that a physician must specifically request testing and may need more than one sample, a practical detail that matters for older adults, people with chronic digestive conditions, and people with weakened immune systems, for whom prolonged diarrhea and dehydration carry greater risk. The parasite life cycle description and the produce washing, preparation and refrigeration guidance draw on U.S. Centers for Disease Control and Prevention material, including CDC/DPDx microscopy of unsporulated and sporulating oocysts, giving caregivers and family members clear steps they can act on at home.*

At a Glance

• 1 - The first cases were diagnosed in 1977 and appeared in medical literature in 1979.
• 2 - Cyclospora measures just 8 to 10 microns across, too small to see with the naked eye.
• 3 - A 1996 multi-state outbreak in the United States was linked to raspberries and strawberries.
• 4 - Cut, peeled, or cooked produce should be refrigerated within two hours and stored away from raw meat, poultry, and seafood.

Topic Definition

Cyclosporiasis

Cyclosporiasis is an infection of the small intestine caused by Cyclospora cayetanensis, a microscopic apicomplexan parasite roughly 8 to 10 microns wide that is swallowed in food or water contaminated with human stool. The parasite invades the lining of the upper small bowel and produces prolonged, often relapsing watery diarrhea together with cramping, gas, nausea, fatigue, appetite loss and weight loss, though some people carry it without any complaints. Its defining feature is a maturation lag: oocysts leave the body in a non infective state and need days to weeks in the environment, depending on temperature and humidity, before they can infect another person, so the illness spreads through contaminated fresh produce, water and surfaces rather than by direct person to person contact. Diagnosis depends on stool examination using specialized techniques that are not part of routine testing, sometimes across several samples, and the infection responds to antibiotic treatment alongside rest and fluid replacement.

Overview

Cyclospora is a single-celled parasite that is too small for a person to see with their naked eye; it is only 8-10 microns in diameter. Its full name is, 'Cyclospora cayetanensis,' although it used to be referred to as, 'cyanobacterium-like, 'coccidian-like,' and, 'Cyclospora-like,' bodies. The first known cases of Cyclospora infection were diagnosed in the year 1977 and reported in medical literature in 1979.

What is Cyclosporiasis?

Cyclosporiasis is an infection of the intestine caused by a parasite called Cyclospora (SIGH-clo-SPORE-uh). A genus of apicomplexan parasites, it includes the species Cyclospora cayetanensis, the causative agent of cyclosporiasis.

Anyone can get cyclosporiasis. The infection can occur in many countries, including the United States, but it is more common in tropical areas. The majority of cases and outbreaks are reported during the spring and summer months, although infections can occur year-round. People who have been infected with Cyclospora can become infected again.

Cyclospora infection causes watery, and sometimes explosive, diarrhea. The one-celled parasite that causes cyclospora infection can enter your body when you ingest contaminated food or water. Fresh produce is the culprit in many cases of cyclospora infection. Cyclospora is acquired by people ingesting something - such as food or water - that was contaminated with the parasite. Cyclospora needs days to weeks after being passed in a bowel movement to become infectious for another person. Therefore, it is unlikely that Cyclospora is passed directly from one person to another.

Since that time, people have been diagnosed with cyclospora infections with increased frequency, in part because of the availability of better techniques for detecting the parasite in stool samples. In the spring of 1996 there was a multi-state outbreak of cyclospora, including cases and suspected cases in northeastern Illinois. In other states in America, investigations have linked infections to the consumption of raspberries or strawberries. Very few cases are reported each year in the state of Illinois. The fact that cyclospora is still a newly recognized infectious organism finds a number of questions in regards to its biology, the way it is spread, and the illness it causes remaining unanswered.

Cyclospora is spread by a person placing something in their mouth that was contaminated with infected stool. For example, the parasite may be transmitted by swallowing contaminated food or water. It is not known how common the various modes of transmission are. It is also not known whether animals may become infected and serve as sources of infection in human beings.

Cyclospora is not infectious at the time it is passed in the stool of a person who is infected. The parasite does not become infectious until days or even weeks after it is passed in the stool. The amount of time depends upon factors such as humidity and temperature. What this means is the spread of cyclospora directly from a person who is infected to another person is unlikely. The potential for indirect spread of infection does exist however. For example, cyclospora may be spread if the stool of a person who is infected contaminates something in the environment such as water, to which another person is then exposed after the parasite has had enough time to become infectious.

Cyclospora and Infection

Unfortunately, people of all ages are at risk of cyclospora infection. While people who travel to tropical countries might be at an increased risk, infection may be acquired in nations to include Canada and the United States of America. The risk might vary with the seasons. Some evidence suggests that infection is more common in spring or summer seasons.

Cyclospora infects a person's small intestine and usually causes an illness characterized by watery diarrhea, with an average of around 6-7 stools each day. Additional symptoms may include:

• Nausea
• Bloating
• Vomiting
• Tiredness
• Weight loss
• Muscle aches
• Increased gas
• Loss of appetite
• Low-grade fever
• Stomach cramps

Some people experience flu-like symptoms before noticing gastrointestinal ones. Others who experience a cyclospora infection do not experience any symptoms at all. The amount of time between becoming infected and the time a person begins experiencing symptoms averages several days and is often around a week, although longer and shorter times have been reported. If the infection remains untreated, the illness associated with it might last for a period lasting from a few days up to a month or even longer and may come back one or more times. Medical science does not know whether or not people with compromised immune systems, such as people with AIDS, more commonly develop severe illness associated with a cyclospora infection.

If you believe you might be infected with cyclospora you should contact your doctor. Identification of the parasite in stool requires specific kinds of laboratory techniques that are not used routinely and your doctor should request testing for the cyclospora parasite. More than one stool sample might need to be checked to find the organism. Your doctor may also want to have your stool checked for other infectious organisms that can cause symptoms that are similar.

A cyclospora infection is treatable with antibiotics. People who are infected and have diarrhea need to rest and drink plenty of fluids. They need to pursue their doctor's advice before taking any medications to slow their diarrhea.

Preventing Cyclospora Infection

Avoiding food or water that might have been contaminated with stool may help prevent Cyclospora infection. Consumers and retailers should always follow safe fruit and vegetable handling recommendations:

• Wash: Wash hands with soap and warm water before and after handling or preparing fruits and vegetables. Wash cutting boards, dishes, utensils, and counter tops with soap and hot water between the preparation of raw meat, poultry, and seafood products and the preparation of fruits and vegetables that will not be cooked.
• Prepare: Wash all fruits and vegetables thoroughly under running water before eating, cutting, or cooking. Fruits and vegetables that are labeled "prewashed" do not need to be washed again at home. 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.
• Store: Refrigerate cut, peeled, or cooked fruits and vegetables as soon as possible, or within 2 hours. Store fruits and vegetables away from raw meat, poultry, and seafood.

Frequently Asked Questions

NOTE: Researched FAQs by Disabled World (DW)

Is there a vaccine for cyclosporiasis

No vaccine is available, so prevention depends on safe water, careful produce handling and good hand hygiene, especially when traveling in tropical regions.

Does chlorine in tap water or swimming pools kill Cyclospora

Routine chlorination is not considered reliable against Cyclospora oocysts, which is why boiled or bottled water is preferred in higher risk areas and why swallowing pool or lake water should be avoided.

Can freezing or refrigerating fruit destroy the parasite

Cold storage is not a dependable way to kill oocysts, so refrigeration should be treated as a food quality and general safety step rather than a way to make contaminated produce safe.

Is cyclosporiasis a reportable illness in the United States

Yes, it is a nationally notifiable condition, and laboratories and clinicians report confirmed cases to state health departments so clusters can be traced to a common food or water source.

How does cyclosporiasis differ from giardiasis or cryptosporidiosis

All three parasites cause watery diarrhea, but they are different organisms that require different laboratory tests and different treatments, so accurate stool identification guides the correct therapy.

Does cooking food destroy Cyclospora

Thorough cooking is considered effective, which is one reason outbreaks are usually tied to raw items such as berries, herbs and leafy salads rather than to cooked dishes.

Should someone with cyclosporiasis stay away from work or school

Direct person to person spread is unlikely, but food handlers, healthcare staff and childcare workers are generally advised to stay away until diarrhea has stopped and to follow local public health guidance.

What should travelers do to lower their risk

Drink bottled, boiled or properly treated water, skip ice of unknown origin, choose cooked vegetables over raw salads, and peel fruit yourself when the local water supply may be contaminated.

Insights, Analysis, and Developments

Editorial Note: What makes Cyclospora unusual among diarrheal parasites is its built in delay - the oocysts a patient sheds are immature and need roughly one to two weeks in the environment before they can infect anyone else, which is why household transmission is rare and why contaminated fresh produce and water supplies, not sick relatives, drive most outbreaks. That biology also explains why outbreak investigators so often end up tracing berries, herbs and salad greens grown in warm climates, and why washing alone is only a partial safeguard. Reported case numbers have climbed since the 1990s largely because laboratories improved at spotting the parasite, so higher counts reflect better detection as much as changing exposure. Several questions remain open, including whether animals act as reservoirs, how much each route of transmission contributes, and whether people with compromised immune systems reliably suffer worse disease. For families, caregivers and food handlers the practical message is steady rather than alarming: rehydrate, avoid antidiarrheal medicines without medical advice, ask directly for Cyclospora stool testing when watery diarrhea drags on past a few days, and treat kitchen hygiene and produce storage as the front line of prevention.*

Author Credentials: Thomas C. Weiss is a researcher and editor for Disabled World. Thomas attended college and university courses earning a Masters, Bachelors and two Associate degrees, as well as pursing Disability Studies. As a CNA Thomas has providing care for people with all forms of disabilities. Explore Thomas' complete biography for comprehensive insights into his background, expertise, and accomplishments.

* Editorial additions by Ian C. Langtree.