Understanding Cyclosporiasis: An Intestinal Illness
Cyclosporiasis is an intestinal infection caused by the microscopic parasite Cyclospora cayetanensis. The illness is characterized by watery diarrhea, which can be frequent and sometimes explosive. According to the Centers for Disease Control and Prevention (CDC), the parasite infects the small intestine, and if left untreated, the illness may persist for a few days to over a month. Symptoms can also follow a relapsing pattern, where they seem to improve before returning one or more times.
The time between exposure to the parasite and the onset of symptoms typically spans about one week, though it can range from two days to two weeks or longer. While the infection is generally not life-threatening, it can lead to severe dehydration. Individuals who are immunocompromised or in poor health may face a higher risk of experiencing a severe or prolonged illness.
Transmission and Outbreak Risks
Cyclospora is spread through the consumption of food or water contaminated with feces. A critical characteristic of the parasite is that it requires one to two weeks in the environment after being passed in a bowel movement before it becomes infectious. Consequently, direct person-to-person transmission is considered unlikely.
In the United States, outbreaks have been linked to various types of fresh produce. Furthermore, the parasite is resistant to chlorine, meaning it can survive in recreational water sources such as swimming pools, splash pads, lakes, and rivers. Because the parasite can persist in the environment, experts suggest that during periods of known outbreaks, it may be prudent to avoid public swimming areas. While the source of recent cases in various states remains under investigation, the illness remains a nationally notifiable disease in 43 states and the District of Columbia.
Diagnosis and Clinical Challenges
Identifying Cyclospora presents a unique challenge for healthcare providers. Standard diagnostic tests for stomach bugs typically do not include the parasite, meaning doctors must specifically request testing for it. Because the parasite is shed in stool intermittently, patients may be required to submit several samples on different days to achieve an accurate diagnosis.
For more on this story, see Cyclospora cases have been reported in several states. What to know about the diarrhea-causing parasite..
If a patient experiences diarrhea lasting longer than 48 hours, infectious disease experts recommend seeking medical evaluation. If a diagnosis is confirmed, the standard treatment involves a seven- to 10-day course of the combination antibiotic sulfamethoxazole-trimethoprim, often sold under trade names such as Bactrim or Septra. For patients with sulfa drug allergies, providers may consider alternative options such as ciprofloxacin or nitazoxanide. Supportive care, including hydration and the use of antidiarrheal medications, may also be recommended.
Prevention and Food Safety
While investigators work to identify the sources of ongoing cases, experts emphasize that raw produce should be handled with care. If you are particularly vulnerable due to age or underlying health conditions, it may be advisable to avoid foods historically linked to outbreaks, which include:
- Raspberries
- Basil
- Salad mixes, including coleslaw and vegetable trays
- Cilantro
- Berry and fruit mixes
- Lettuce
- Snow peas
Cooking fruits and vegetables is the most reliable method for eliminating the parasite; reaching an internal temperature of 158 degrees Fahrenheit or higher kills Cyclospora. For produce that cannot be cooked, washing is recommended, though studies indicate that even careful rinsing is not entirely reliable for removing the parasite. Rinsing produce while scrubbing firm items with a soft brush, as well as discarding the outer leaves of lettuce, may help reduce risk.
When to Seek Emergency Care
Patients should seek immediate medical attention at an emergency room if they exhibit signs of severe dehydration, such as confusion, dizziness, or a significant decrease in urination. Individuals with weakened immune systems should also go to the emergency room if they develop any symptoms of an infectious disease. If symptoms persist or worsen after completing a full course of prescribed antibiotics, patients are advised to contact their healthcare provider again for follow-up.
