Cyclospora cayetanensis

Background

Epidemiology

• Humans are the only known host
• Worldwide distribution; endemic in developing countries with outbreaks in developed countries
• Acquired via contaminated food or water, especially raspberries, watercress, lettuce, basil, cilantro, etc.
  • Essentially, produce that is difficult to wash
• Outbreaks each summer

Life Cycle

• Oocysts are quite resistant, and require sporulation in the environment before they are infectious
  • Each contains two sporocysts, each of which in turn contains two sporozoites

Clinical Presentation

• Primarily causes an opportunistic infection
• Causes an acute or chronic diarrhea
  • Usually present sooner than, for example, Giardia lamblia, since they're more unwell
• More inflammatory than some of the other intestinal protozoa, with more fevers and malaise
• Complications can include reactive arthritis and Guillain-Barré syndrome

Diagnosis

• Stool microscopy with stool acid-fast staining, often requiring multiple samples
  • The oocytes are shed only intermittently, so need many stool samples to get adequate sensitivity
• PCR

Management

• Treated with trimethoprim-sulfamethoxazole DS po bid for 7 to 10 days
  • Alternative: ciprofloxacin 500 mg po bid for 7 days