Cyclospora Infection (Cyclosporiasis)

What is Cyclospora Infection?

Cyclospora infection is caused by a protozoan parasite called Cyclospora cayetanensis that infects the intestine and causes a disease called cyclosporiasis. It occurs due to ingestion of food and water that is contaminated with fecal matter. It is characterized by watery diarrhea, abdominal cramps, bloating and other symptoms. It is commonly called "traveler’s diarrhea" as it is prevalent in travelers returning from endemic areas where this protozoan parasite is prevalent.

Epidemiology of Cyclospora Infection

Cyclospora cayetanensis is an intestinal protozoon that is endemic (regularly found) in Peru, Haiti, Guatemala, and Nepal. The first known human cases of cyclosporiasis were described in 1979 by Dr. R.W. Ashford, a British parasitologist, while working in Papua New Guinea. In 1994, the complete morphology of the protozoon was characterized in Cayetano Heredia University in Lima, Peru, from where the species name "cayetanensis" is derived. In 2007, Indian researchers reported for the first time that the disease was associated with Bell’s Palsy. Though largely confined to endemic areas of the globe, several outbreaks arising from imported food products have been reported from USA in recent years. The annual incidence of Cyclospora infection is estimated to be about 21 per 100,000 of all food-borne illnesses in USA.

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How Does Cyclospora Infection Spread?

Cyclospora infection spreads through the fecal-oral route by the following modes:

• Contaminated Food & Water: Cyclospora can rapidly spread through contaminated food and contaminated water.
• Poor Hygiene & Sanitation: Cyclospora can spread rapidly by improper disposal of feces. This underscores the need for proper sanitation and hygienic practices
• Soil & Animals: Farmers and persons involved in animal husbandry are at greater risk due to exposure to soil and animals.
• Low Socioeconomic Status: Cyclospora can be spread by people from low socioeconomic strata as they usually lack adequate health education, which can lead to unhygienic practices.

What are the Causes of Cyclospora Infection?

The primary cause of cyclospora infections is through consumption of contaminated food and water. This can occur as a result of improperly prepared food such as undercooked food, unwashed vegetables and fruits, and lack of hand hygiene. These practices can result from ignorance or simply due to carelessness.

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What are the Symptoms & Signs of Cyclospora Infection?

Some people may not exhibit any symptoms at all. Others may develop symptoms within a week after consuming contaminated food or water, which can last up to a month or even longer in case for a weakened immune system. Some of the main symptoms and signs of cyclospora infection include the following:

• Frequent (often explosive) watery diarrhea
• Bloating and flatulence
• Abdominal cramps
• Loss of appetite and weight loss
• Nausea and vomiting
• Fatigue and malaise
• Low-grade fever

What are the Consequences of Cyclospora Infection?

Since cyclospora infections respond to appropriate treatment, severe consequences usually arise only in the absence of treatment. Some of the long-term consequences of cyclospora infections may include the following:

• Reiter’s syndrome
• Guillain-Barré syndrome
• Acalculous cholecystitis
• Malabsorption syndrome
• Prolonged diarrhea and severe dehydration

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How do you Diagnose Cyclospora Infection?

Diagnosis is essentially based upon Stool Examination. This may involve standard methods such as light microscopy or some advanced techniques, which are highlighted below:

• Light Microscopy: Stool examination by light microscopy is a routine test for parasite identification. Often acid-fast staining is used to stain the parasites before observing under the microscope. The procedure often requires multiple stool samples in order to get a positive diagnosis.
• Advanced Microscopic Techniques: If light microscopy fails to identify the pathogen, there are two other highly sensitive visualization techniques that can be used for stool examination. These include phase-contrast microscopy and immunofluorescence. However, these techniques are not used routinely but only in special circumstances.
• Polymerase Chain Reaction (PCR): This is the most sensitive molecular test for confirmation of Cyclospora cayetanensis in a stool sample. This involves detection of the parasite DNA in the sample. If parasite-specific DNA is present, it indicates a positive test. However, this test is generally reserved for research purposes.

How can you Treat Cyclospora Infection?

General measures for diarrhea should be adopted such as drinking plenty of fluids and adequate bed rest. If necessary, intravenous fluids may need to be administered. Specific treatment involves administration of the antibiotic Trimethoprim-Sulfamethoxazole as a 7-day course. No other antibiotic has been found to be effective against Cyclospora cayetanensis, which is a drawback for patients who may be allergic to sulfa drugs. This drug is not recommended for pregnant women.

How do you Prevent Cyclospora Infection?

Cyclospora infection can be prevented by following the undermentioned strategies:

• Drinking purified or boiled water.
• Washing hands before, during, and after food preparation.
• Washing hands with soap and water after using the toilet.
• Making sure that food is steaming hot.
• Washing and peeling fruits and vegetables before consumption.
• Improvement of sanitary conditions.