entamoeba histo
TRANSCRIPT
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Entamoebahistolytica
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BIOLOGY
Pseudopod-forming nonflagellaleted
Trophozoites highly motile Has pseudopodia Multiply by binary fission
Lacks organelles (resembles mitochondria)
No RER or Golgi apparatus
Mode of transmission Ingestion from fecally-contaminated material Venereal transmission through fecal-oral contact Direct colonial inoculation through contaminated enema
equipment
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CYSTS
-4 NUCLEI-CENTRALLYLOCATEDKARYOSOMES-FINE,UNIFORMLY
DISTRIBUTEDPERIPHERALCHROMATIN.-MEASURE 12 TO15 M.
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LIFE CYCLE
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PATHOGENESIS AND CLINICAL MANIFESTATIONIN HUMANS
Pathogenic
infection can lead to amoebic dysentery or
amoebic liver abscess
Symptoms can include fulminating dysentery
bloody diarrheaweight loss
fatigue
abdominal pain
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asymptomatic infection ("luminal amebiasis)
invasive intestinal amebiasis (dysentery,colitis, appendicitis, toxic megacolon,amebomas)
invasive extraintestinal amebiasis (liverabscess, peritonitis, pleuropulmonaryabscess, cutaneous and genital amebiclesions)
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DIAGNOSIS OF INFECTION
Infective stage : Quadrinucleated cyst(having 4 nuclei)
Diagnostic stage : trophozoite
Direct Fecal Smear (DFS) and staining
Enzyme immunoassay (EIA); IndirectHemagglutination (IHA); Antigen detection monoclonal antibody andPCR
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Iodamoebabtschlii
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BIOLOGY
Cysts vary from being nearly spherical to ellipsoidal
measure 5-20 m
single nucleus that is not visible in eitherunstained or iodine-stained wet mounts
With permanent stains (such as trichrome), thenucleus contains a large, usually eccentrickaryosome
presence of a large compact mass (vacuole)of glycogen in the cyst stage.
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Trophozoites
measure 8 to 20 m
single nucleuswith a large
usually central karyosome
surrounded by refractile, achromatic
granules.Cytoplasm
coarsely granular
Vacuolated
can contain bacteria, yeasts or othermaterials.
Movement in living trophozoites is sluggish anddescribed as nonprogressive.
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LIFE CYCLE
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PATHOGENESIS AND CLINICAL MANIFESTATIONIN HUMANS
Non-pathogenic
Causes amebiasis in immunologically
compromised individuals
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DIAGNOSIS OF INFECTION
Infected form: Mature, uninucleated cysts
identification is made by observing cysts
and/or trophozoites in stool specimens, bothconcentrated wet mounts and permanentstained smears.
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Naegleria fowleri
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BIOLOGY
does not form cysts in human tissues
two forms of trophozoites Ameboid(trophozoite form) Ameboflagellate (swimming form)
Ameboid measure 10-35 m but when rounded are usually 10-15 m in diameter
In culture, trophozoites may get over 40 m
cytoplasm is granular and contains many vacuoles
Nucleus Single large and has a large, dense karyosome lacks peripheral chromatin
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Flagellate small pear-shaped
with two long whip-like flagellae at one end
very mobile stage that infects people
Amoeba
slow moving single-celled organism thatproliferates by dividing repeatedly.
Returned to water, and occasionally in humanspinal fluid, the amoeba will once again assumethe flagellate form.
Cyst tough spherical stage found only in the
environment, forms when conditions areunfavorable for naegleria.
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LIFE CYCLE
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PATHOGENESIS AND CLINICAL MANIFESTATION IN HUMANS
Acute primary amebic meningoencephalitis(PAM) severe headache
other meningeal signs
Fever
vomiting
focal neurologic deficits
progresses rapidly (
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DIAGNOSIS OF INFECTION
microscopic examination of cerebrospinalfluid (CSF).
Wet mount may detect motile trophozoites,and a Giemsa-stained smear will showtrophozoites with typical morphology