ISOSPORA BELLI
It is a coccidian parasite which can cause diarrhea
in humans.
It discovered d by Virchow in 1860 but
named in 1923 by wenyen
Habitat
Found in small and large
Intestine
Distribution
African,south American
Countries
Morphology
Single form-oocyst
Elipsoidal shape or
elongated oval shape
Size 20-3010-19
Each oocyst is surrounded by a
thin smooth two-layered
Immature oocysts seen in the
feces of patients con tain
two sporoblasts.
The oocysts mature outside the body
Two sporoblasts result in form sporocyst
Inside sporocyst develop 4 sporozoites
Size of sporozoites 9-147-12
Life cycle
Asexual-merogony
Sexual -gametogony
Sporozoites released in human
when ingestion of
Contaminated food or water
Sporozoites invades intestinal epithelial layers
Form merozoites this happened in
Upper intestine
Infection start from s.intestine
Form micro(20-25)¯ogamete(1)
1 microgamete fertilize 2 macrogamete
After fertilization zygote form
Immature sporoblasts
Released in feces
Sporoblasts convert into sporocyst
Which produce 4 sporozoites
Sporozoites infective form it
cause infection
Pathogenesis
Mostly assymtopmatic
Immunocompetent- mild diarrhoea
Resolve back in 5-6 weeks
without any treatment
Immunocompromised -general complications
Major complications - respiratory infection
Lympadenopathy,splenomegaly
Lab diagnosis
Sample: stool
Wet mount, iodine solution
Acid fast staining &
fluroscence staining
Stool concentration method
Molecular method -PCR,ELISA
Treatment
Antimicrobial drugs-
Co trimoxazole
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Introduction
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