Amoeba Flashcards
What are the intestinal amoebas?
Entamoeba: histolytica
hartmanni
coli
polecki
Endolimax nana
Iodamoeba butschlii
What are the extra-intestinal amoebas
Nemonic: NEA
Naegleria fowleri
E. gingivalis
Acanthamoeba species
Entamoeba - small karyosome near center of nucleus
Endolimax - large karyosome with achromatic threads
Iodamoeba - large karyosome rich in chromatin with a single layer of periendosomal granules
REMEMBER 👆
Amoeba cyst have?
Nemonic: GMC
Chromatoidal bars
Glycogen vacuoles
More than 1 nucleus (usually 4)
Ovoidal/round shape
Amoeba trophozoite have?
Bacteria & food particles RBC fragments Pseudopods (motility) Only one nucleus Irregular in shape
Considered as the pathogenic amoeba in humans?
Entamoeba histolytica
Entamoeba histolytica causes?
Nemonic: LAAA
Amoebiasis
Amoebic dysentery
Amoebic hepatitis
Liver abscess
Refers to the life cycle in which the cyst becomes a trophozoite?
Excystation
Refers to the life cycle in which the trophozoite becomes a cyst/precyst?
Encystastion
EXcystation of E. histolytica occurs in?
Duodenum
Maturation of metacystic trophozoite (E. coli) occurs in?
Cecum
Trophozoite parasite that has a ground glass appearance?
E. histolytica
What factor initiates ENcystation of E. histolytica?
Unfavorable environment
Considered as the small race of E. histolytica.
E. hartmanni
S/Sx of E. histolytica depends on?
Location of parasite to host
Extent of tissue invasion
What are the manifestations of Amebic colitis?
Abdominal pain Blood and mucus in stool Diarrhea Cramping Anorexia Flatulence
Acanthamoeba spp can cause?
Nemonic: MADS
Meningoencephalitic syndrome
Amoebic keratitis
Dissemination and granuloma formation
Skin lesions
The diagnostic morphology/ characteristics of acanthamoeba spp trophozoite.
Slender hyaline projections (acanthopods)
A disease characterized by severe unilateral pain, with stromal infiltrates of the cornea, recurrent corneal epithelial breakdown and has corneal lesions refractory to usual medications.
A parasitic disease associated with the use of contact lenses.
Amoebic keratitis
A parasitic disease characterized by necrotizing subacute or chronic granulomatous encephalitis with trophozoite and cyst present in inflammatory cells.
Granulomatous amoebic encephalitis
True or false. Acanthamoeba spp is an opportunistic parasite to immunocompromised px.
TRUE
What is the treatment for Ancanthamoeba spp infection?
No treatment (trick question)
Corneal biopsy specimens for amoebic keratitis are stained with?
Clue: PAS
Giemsa or Periodic Acid Schiff
Naeglaria fowleri can cause?
Clue: PAM
Primary amoebic meningoencephalitis
N. fowleri specimen can be obtained through?
CSF extraction
It is the only amoeba that has 3 morphologic form.
Enumerate the 3 morphologic forms
Nemonic: AFC
Naegleria fowleri
Ameboid trophozoite
Flagellates
Cyst
Considered as the infective stage of N. fowleri that causes PAM (Primary Amoebic meningoencephalitis)?
Amoeboid trophozoite
What are the similarities morphologic characteristics of the 3 forms of N. fowleri?
1 nucleus
Large central karyosome
Peripheral chromatin absent
Cytoplasm is granular with vacuoles
N. fowleri is commonly found in?
Contaminated warm bodies of water.
A parasitic disease that causes rapid tissue destruction in the brain followed by sx of meningitis.
Primary Amoebic Meningoencephalitis
What parasitic form is present PAM (Primary Amoebic meningoencephalitis)?
Ameboid trophozoite
Defined as a diagnostic sign for meningitis in which px is unable to fully straighten leg when hip is flexed at 90 degrees because of hamstring stiffness.
Kernig sign
What is the treatment for N. fowleri?
Amphotericin B + Rifampicin & Miconazole
Px untreated with N. fowleri infection usually dies within?
3-6 days
What amoebas are similar to E. histolytica?
E. dispar & E. hartmanni
True or false Dientamoeba fragilis has trophozoite and cyst stage?
False, only trophozoite
What are the morphological characteristics of Dientamoeba fragilis?
Pseudopods (leaf like) Bacteria in food vacuoles Binucleated No RBC in cytoplasm Nuclear membrane has NO chromatin granules
What is the main habitat Dientamoeba fragilis?
Large intestine
A parasitic disease that causes low grade superficial irritation of the mucosa resulting in excess secretion of mucus, diarrhea and abdominal pain.
Dientamoebiasis/Hakansson’s syndrome
What type of stool is E. histolytica trophozoites found?
Diarrhetic/Liquid stool/Desenteric
Stool specimen should be examined after how many minutes?
Within 30 mins
Preservatives used in preserving E. histolytica?
Nemonic: MPS
Merrhiolate idodine formaldehyde
Polyvinyl alchohol
Schaudinn’s fixative
What type of stool is E. histolytica cyst found?
Formed/Solid stool
Culture medium for E. histolytica
Dibasic medium of Beock
DR bohlav
At what boiling point are E. histolytica cysts killed?
55 degrees
What are the characteristics of Amoebic dysentery?
Nemonic: GRODA
Gelatinous mixture of blood, feces & mucus
Relatively copious
Offensive odor
Dark red
Acidic
True or false. E. gingivalis has both trophozoite and cyst stage.
False, only trophozoite.
What is the main habitat of E. gingivalis?
Mouth
What are the morphological characteristics of E. gingivalis?
Food vacuoles with partly digested leukocytes
Has zone of demarcation between clear ectoplasm & granular endoplasm
Has multiple pseudopodia
Well defined karyosome near the nucleus
Nuclear membrane closely packed with chromatin granules
What are the five stages of E. coli?
Nemonic: CMMTP
Cyst
Metacyst
Metacystic trophozoite
Trophozoite
Precyst
How many nuclei does E. coli cyst usually have? Max?
8, 16
What are the characteristics of a E. coli cyst?
Eccentrically located karyosome
No cytoplasmic inclusions
Where does E. coli undergo excystation?
Small intestine
Maturation of metacystic trophozoite to trophozoite (E. coli)
Large intestine
What are the morphological characteristics of E. coli troph?
in NSS it is colorless
Endoplasm highly vacuolated
Karyosome eccentrically large
Nuclear membrane has coarse chromatin granules
When does E. coli undergo encystation?
When there are unfavorable conditions in the LARGE INTESTINE
Do precyst of E. coli have cytoplasmic inclusions? Yes or No? If yes what are they?
Yes
Glycogen mass
Chromatoidal rods
REMEMBER: CYST has no cytoplasmic inclusions.
ONLY PRECYST has inclusions
When does an E. coli cyst considered matured?
When it has 8 nuclei
True or false Endolimax nana has both trophozoite and cyst stage?
TRUE
What are the morphological characteristics of Endolimax nana TROPH
Has NARROW RIM of cytoplasm
Subspherical nucleus with irregular nucleus.
Cytoplasm is granular and vacuolated with bacteria
True or false. A mature Endolimax nana cyst has 1-2 nucleus.
False, 4 nuclei
Immature: 1-2
Mature: 4
What are the morphological characteristics of Endolimax nana?
ill defined glycogen mass
Small slightly curved chromatoidal bodies
What are the morphological characteristics of Iodamoeba butschlii TROPH?
Short and broad pseudopodia
Clear ectoplasm
Large Karyosome with achromatic eccentric granules on one side
True or false. Iodamoeba butschlii TROPH is found in formed stools.
False, Unformed/diarrhetic stool
What are the morphological characteristics of a Iodamoeba cyst?
Guide: Ioda’ sister has a large KID!
Large KIDNEY SHAPE glycogen vacuole
Irregular pyriform
Uninucleate/one nucleus
