Cystoisospora belli: Difference between revisions

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

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

@@ Line 1: / Line 1: @@
+== Background ==
+=== Epidemiology ===
-{{DISPLAYTITLE:''Isospora belli''}}
+* 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 [[Usual incubation period::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 ==
+* 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''}}
 [[Category:Protozoa]]
 [[Category:Gastrointestinal infections]]