Protozoa: Amebea Flashcards
-Entamoeba -Endolimax -Iodamoeaba -N. fowleri -Acanthamoeba -Balamuthia mandrillaris
What are the intestinal amebae? (3)
- Entamoeba
- Endolimax
- Iodamoeba
Entamoeba histolytica:
-Morphologically indistinguishable from?
E. dispar
*nonpathogenic
Entamoeba histolytica:
-Morphologically similar to?
- E. coli
- E. hartmanni
What is the only feature that can differentiate E. histolytica from E. dispar?
Erythrophagocytosis (E. histolytica)
Entamoeba histolytica - Trophozoites:
- Size
- Nucleus (2)
- Cytoplasm
- Motility
-15-20 um Nucleus: -small, central karyosome -fine peripheral chromati Cytoplasm: -"ground glass" appearance (+/- ingested RBCs) Motility: -Unidirectional*
*E. coli/E.hartmanni are NONdirectional
Entamoeba histolytica - Cysts:
-Characteristics (2)
- Cysts have up to 4 nuclei
- Chromatoidal bodies w. smooth rounded ends
Entamoeba histolytica:
-Diagnosis method
Stool EIA > Stool microscopy
Entamoeba histolytica:
- Transmission
- geographic distribution
Ingestion of Cysts in fecally contaminated food or water
-Worldwide distribution
Entamoeba histolytica - Clinical features:
- S/S
- Histological findings/location
- Complications (2)
- Asymptomatic–Protracted diarrhea
- “flask shaped” ulcer (cecum MC)
- Invades intestinal wall and disseminates to liver
- Amebic abscesses (Anchovy Pastelike)
Entamoeba Coli Vs. E. histolytica - Trophozoites:
- Size
- Karyosome
- Chromatin
- Larger than E. histolytica (20-25 um)
- Large, Eccentric karyosome
- Clumped, peripheral chromatin
Entamoeba Coli Vs. E. histolytica - Cysts:
- Nuclei
- Chromatoidal bars
- Up to 8 nuclei (E. histolytica/hartmanni Never >4)
- Frayed (splintered) chromatoidal bodies
Entamoeba hartmanni Vs. E. histolytica - Trophozoites:
-Most distinguishing characteristic
SMALL
- Trophozoite (5-10 um)
- Cyst (5-8 um)
Endolimax nana.
-Characteristic feature (1)
Large, knobby “ball and socket” central karyosome
Iodamoeba butschlii.
-Characteristic features (2)
- Prominent iodine staining vacuole
- Large “ball and socket” central karyosome
Free living amebae are found widely in the environment, what are the species that are opportunistic human pathogens? (3)
- Naegleria fowleri
- Acanthamoeba spp.
- Balamuthia mandrillaris
Naegleria fowleri:
- Causes
- Transmission
- Pathophysiology
- Primary amebic menignoencephalitis (PAM)
- Warm stagnant fresh water
- Enters through nasal cavity - frontal lobe via olfactory nerve (running through cribriform plate)
Naegleria fowleri:
-Where are trophozoites found?
CSF or meninges and surrounding brain tissue
Naegleria fowleri - Trophozoites:
- Size
- Nucleus/karyosome
- 10-35 um
- Small nucleus with a large, dense central karyosome
Naegleria fowleri:
-Culture
Lawn of bacteria (E. coli)
Naegleria fowleri:
-CSF handling
Do NOT refrigerate
Acanthamoeba spp. and Balamuthia mandrillaris both cause what?
Granulomatous Amebic Encephalitis (GAE)
Granulomatous Amebic Encephalitis (GAE):
- Source
- Brain involvement
-Cutaneous or Pulmonary source
Hematogenous dissemination to brain
-Organisms found in perivascular spaces
What organism is responsible for amebic keratitis in contact lens wearers?
Acanthomeba spp.
Acanthamoeba spp./Balamuthia mandrillaris - Identication:
-Cysts (3)
- 2 walls
- 1 nucleus
- Large karyosome
Acanthamoeba spp./Balamuthia mandrillaris - Identication:
-Trophozoites (3)
- Pleomorphic
- Small nucleus
- Large central karyosome