Cyclosporiasis and Its Causes

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Questions and Answers

What is the primary mode of transmission for Cyclospora cayetanensis?

  • Ingestion of contaminated food or water (correct)
  • Direct skin contact
  • Contact with infected animals
  • Inhalation of spores

What size is the mature oocyst of Cyclospora?

  • 5-7 μm
  • 10-12 μm
  • 8-10 μm (correct)
  • 12-15 μm

Which clinical feature is typically associated with severe infection in immunocompromised individuals?

  • Fever without other symptoms
  • Persistent cough
  • Mild abdominal cramping
  • Severe diarrhea (correct)

What is observed in intestinal biopsy of a Cyclospora infection?

<p>Shortening of villi (C)</p> Signup and view all the answers

What is the incubation period for Cyclospora infection?

<p>1-7 days (D)</p> Signup and view all the answers

How can Cyclospora oocysts be identified in stool examination?

<p>By direct wet mount demonstration (B)</p> Signup and view all the answers

What staining technique is recommended for visualizing Cyclospora oocysts?

<p>Modified Ziehl-Neelsen stain (A)</p> Signup and view all the answers

Which of the following regions is NOT commonly associated with Cyclospora infections?

<p>Australia (B)</p> Signup and view all the answers

Flashcards

Cyclosporiasis infection

Infection caused by a coccidian parasite, Cyclospora cayetanensis, resulting in prolonged diarrhea.

Cyclospora cayetanensis

Specific type of coccidian parasite causing cyclosporiasis.

Cyclospora oocyst (morphology)

Round-shaped structure, 8-10 μm size, containing sporocysts and sporozoites (spores of the parasite).

Oocyst sporulation

The process of an immature oocyst developing into a mature, infectious structure.

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Transmission of Cyclospora

Ingestion of contaminated food or water containing the sporulated oocysts.

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Cyclospora life cycle

A cycle involving the development of oocysts within the human intestine, sporulation of the oocyst outside the host, and infection of humans via ingestion of sporulated oocysts in food/water.

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Clinical features of Cyclosporiasis

Diarrhea, fatigue, loss of appetite, nausea, vomiting, cramps, and fever. May be asymptomatic in immunocompetent individuals.

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Diagnosis of Cyclosporiasis

Detection of Cyclospora oocysts in stool samples via wet mount, modified Ziehl-Neelsen staining, or ultraviolet illumination, as well as intestinal biopsy for microscopic examination.

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Study Notes

Cyclosporiasis

  • Caused by Cyclospora spp., a coccidian parasite
  • Causes prolonged diarrhea, including traveler's diarrhea
  • Cyclospora cayetanensis is a specific type
  • Infection reported in South E Asia, Papua New Guinea, Indonesia, India, Pakistan, Nepal, Middle East, Africa, UK, USA, South and Central America, and the Caribbean
  • Oocysts are spherical, 8-10 µm in size
  • Sporulated (mature) oocyst round, 8-10 µm, contains two sporocysts, each containing two sporozoites
  • Unsporulated (immature) oocyst, passed in feces, contains central morula with 6-9 refractile globules.
  • Life cycle not fully understood, possibly with both asexual and sexual cycles in the intestine via ingestion of contaminated food or water
  • Sporulated oocysts are infectious to humans
  • Oocysts shed in feces sporulate outside the host, becoming infectious
  • Humans acquire infection by ingestion of food or water contaminated with oocysts
  • Sporozoites are released from the sporocysts, infecting enterocytes in the small intestine
  • Sporozoites develop into unsporulated oocysts and excreted in feces
  • Incubation period is 1-7 days
  • Symptoms include diarrhea, fatigue, loss of appetite, nausea, vomiting, cramps, and fever (often severe in immunocompromised)
  • Sometimes asymptomatic, especially in immunocompetent individuals
  • Intestinal biopsy shows villous atrophy and blunting, lymphocyte infiltration of lamina propria, and increased lymphocytes in intestinal epithelial cells

Diagnosis

  • Stool examination shows round oocysts, observed with wet mount examination, acid-fast stain
  • UV epifluorescence microscopy shows acid-fast autofluorescence oocysts,
  • Molecular diagnosis with rt-PCR
  • Serology for antibody detection
  • Histopathology of intestinal biopsies
  • Direct wet mount demonstration of oocysts in feces
  • Modified Ziehl-Neelsen stains for oocysts (ovoid and acid-fast red colored)
  • Oocysts of Cyclospora are acid-fast and stain red in color.
  • Unsaturated oocysts of C. cayetanensis are autofluorescent under UV illumination.

Treatment

  • Rehydration in serious cases; no treatment needed in mild cases
  • Cotrimoxazole, tetracycline, and folic acid have been used
  • HIV-infected patients may require long-term suppressive maintenance therapy.

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