Cystoisospora belli: Difference between revisions

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Cystoisospora belli
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=== Epidemiology ===
=== Epidemiology ===
* Worldwide, but more in tropical and subtropical areas
* Worldwide, but more in tropical and subtropical areas
* Can have outbreaks with daycare, animal exposures
* Mostly associated with HIV infection, but can also cause a traveller's diarrhea
* Mostly associated with HIV infection, but can also cause a traveller's diarrhea


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* The merozoites go through asexual reproduction, eventually followed by sexual reproduction that results in development of an immature oocyst, which is shed
* The merozoites go through asexual reproduction, eventually followed by sexual reproduction that results in development of an immature oocyst, which is shed


== Clinical Presentation ==
== Clinical Manifestations ==
* Incubation period of 1 week
* Incubation period of [[Usual incubation period::1 week]]
* Watery diarrhea with abdominal cramping, malaise, anorexia, and weight loss
* Watery diarrhea with abdominal cramping, malaise, anorexia, and weight loss
* Fever, if it occurs, is low-grade
* Fever, if it occurs, is low-grade
* One of the only intestinal protozoa that can cause a peripheral '''eosinophilia'''
* Lasts 2 to 3 weeks, but can continue to shed oocysts for weeks after
* Lasts 2 to 3 weeks, but can continue to shed oocysts for weeks after


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* Includes HIV (CD4 <200) and chemotherapy
* Includes HIV (CD4 <200) and chemotherapy
* Disease course may be more severe and may be chronic
* Disease course may be more severe and may be chronic
* Can include hemorrhagic colitis
* Can include '''hemorrhagic colitis'''


== Management ==
* In HIV patients:
** [[Is treated by::Trimethoprim-sulfamethoxazole]] DS po qid for 10 days
** Alternative: [[Is treated by::ciprofloxacin]] 500 mg po bid for 7 days then three time weekly, [[Is treated by::pyrimethamine]] 75 mg po daily with folinic acid, or [[Is treated by::nitazoxanide]]


{{DISPLAYTITLE:''Cystoisospora belli''}}

{{DISPLAYTITLE:''Cystisospora belli''}}
[[Category:Protozoa]]
[[Category:Protozoa]]
[[Category:Gastrointestinal infections]]
[[Category:Gastrointestinal infections]]

Latest revision as of 13:48, 5 August 2020

Background

Epidemiology

  • Worldwide, but more in tropical and subtropical areas
  • Can have outbreaks with daycare, animal exposures
  • Mostly associated with HIV infection, but can also cause a traveller's diarrhea

Life Cycle

  • Oocysts are shed into the environment
    • Each contains one sporoblast
    • Remain viable for months
  • Oocysts sporulate in the environment before becoming infectious
    • Sporoblasts dividing and maturing into two sporocysts, which in turn divide and mature into two sporozoites each
  • The sporulated oocyst (containing four sporozoites) is ingested
  • In the proximal small bowel, the sporozoites are released and develop into merozoites
  • The merozoites go through asexual reproduction, eventually followed by sexual reproduction that results in development of an immature oocyst, which is shed

Clinical Manifestations

  • Incubation period of 1 week
  • Watery diarrhea with abdominal cramping, malaise, anorexia, and weight loss
  • Fever, if it occurs, is low-grade
  • One of the only intestinal protozoa that can cause a peripheral eosinophilia
  • Lasts 2 to 3 weeks, but can continue to shed oocysts for weeks after

Immunocompromised patients

  • Includes HIV (CD4 <200) and chemotherapy
  • Disease course may be more severe and may be chronic
  • Can include hemorrhagic colitis

Management