LECTURE 8: THE AMEBAS Flashcards
are extensions of cytoplasm providing motility
unique to amebae.
Pseudopods
stages that are part of the amebae life cycle.
Trophozoite and cyst
the infective stage of Amebas
Cyst
the active
reproduction stage destroyed by stomach acid.
Trophozoite
one of the most important criteria for identification
Size
(in liquid stools)
trophozoites
(in formed stools)
cysts
Area of chromatin within the nucleus
. Karyosome
Nucleic acid combined with a protein found along the nuclear membrane
Peripheral chromatin
Development of a cyst into a trophozoite
Excystation
Development of a trophozoite into a cyst
Encystation
Rod-shaped, RNA containing structure found in
the cytoplasm
Chromatoid bar
The only ameba pathogenic for the gastrointestinal tract
Entamoeba histolytica
The only member of the family of Entamoeba parasites to cause colitis and liver abscess
Entamoeba histolytica
Entamoeba histolytica cyst’s range size
8-22 um, spherical
Entamoeba histolytica’s cyst contains how many nuclei
1-4
Entamoeba histolytica’s karyosome is located.
centrally
E. histolytica trophozoites range in size from
8-65 um
The presence of intracellular RBCs in intestinal amebae is considered diagnostic of
Entamoeba histolytica
Entamoeba coli cyst’s range is
8-40 um
Entamoeba coli cysts contains how many nuclei
1-8 nuclei
Entamoeba coli’s karyosome is
eccentric and large
The cytoplasm of Entamoeba coli’s cyst is coarse with thin chromatoid bars with
pointed ends
Entamoeba coli’s trophozoites range is
10-60 um
E. coli trophozoites contains how many nucleus
1 or single
The cytoplasm of Entamoeba coli is
coarse and vacuolated, with
bacterial inclusions.
Excystation occurs in the
small or large bowel
Entamoeba histolytica trophozoites multiply by
binary fission
Characterized by abdominal cramping, anorexia,
fatigue, and diarrhea.
Amebic colitis
Cause ulcers and amebic dysentery (blood and
mucus in the stool).
Amebic colitis
Involves infections of the liver, but it is a rare
complication. Spleen, brain, and lungs is affected
Extraintestinal amebiasis
diagnosis of Entamoeba histolytica and Entamoeba coli is accomplished mainly by
Wet preparation and permanent staining of
stool sample
A special medium known as
TYI-S-33
Intestinal infections are treated with
Paromomycin, diloxanide furoate (Furamide), or Metronidazole (Flagyl)
it is relatively similar to that of E.
histolytica apart from its smaller size.
Entamoeba hartmanni
it does not ingest red blood cells.
Entamoeba hartmanni
Entamoeba polecki is usually found in the …
intestines of pigs and monkeys.
it has sluggish motility
Entamoeba polecki
Smallest amoeba. Size = RBC
Endolimax nana
Food vacuoles of Endolimax nana found in the cytoplasm may contain
Bacteria
Cysts measure about the same size as trophozoites
Endolimax nana
Nuclei resembles cross eyed
appearance.
Endolimax nana
surrounded by achromatic granules.
Iodamoeba butschlii
has a large glycogen body which stains
dark brown with iodine
Iodamoeba butschlii
Iodamoeba butschlii’s specific diagnosis is done through …
Stool examination and Formalin ether/ethyl acetate concentration technique (FECT)
and iodine stain are useful to differentiate the species.
Entamoeba gingivalis’ common name
Asymptomatic mouth and genital tract infections.
This species has no cyst stage.
Entamoeba gingivalis
Entamoeba gingivalis’ MOT
Kissing, spray droplets, or by sharing utensils.
what are the free-living pathogenic species …
Naegleri fowleri
Acanthamoeba spp.
What is the common name of Naegleri fowleri
Brain eating amoeba
What is the common associated disease of Naegleri fowleri
Primary amebic meningoencephalitis (PAM).
it is a free-living amoeba
Naegleri fowleri
It inhabits the CNS
Naegleri fowleri
it does not indicate fecal contamination
Naegleri fowleri
It is usually found in lakes, ponds, and swimming pools where the water is warm.
Naegleri fowleri
The only ameba with three known morphologic forms—ameboid trophozoites, flagellate forms, and cysts.
Naegleri fowleri
Naegleri fowleri cyst’s size
10 to 13 um
What are the 3 morphologic forms of Naegleri fowleri
ameboid trophozoites, flagellate forms, and cysts.
Has a cysts contain a single nucleus, without
peripheral chromatin.
Naegleri fowleri
Naegleri fowleri’s karyosomes is
centrally located and large.
Naegleri fowleri’s trophozoites size is
10 to 23 um
The trophozoite’s cytoplasm of Naegleri fowleri is …
granular and vacuolated
Naegleri fowleri’s flagellates size range is …
7 to 15 um
Naegleri fowleri’s flagellate has a what shape …
pear shape
What is Naegleri fowleri’s infective stage
Trophozoite
Trophozoites of Naegleri fowleri infect humans or animals by penetrating the …
Nasal mucosa
Trophozoites of Naegleri fowleri migrates to the brain via
olfactory nerves.
The trophozoites of Naegleri fowleri replicate by
Promitosis
Pathogenesis and clinical manifestation of Naegleri Fowleri
Primary amebic meningoencephalitis (PAM)
Primary amebic meningoencephalitis (PAM) is the pathogenesis and clinical manifestation of …
Naegleri fowleri
It presents as fever, nausea, vomiting, headache,
nuchal rigidity, and mental status changes, with rapid
progression to coma and death.
Primary amebic meningoencephalitis (PAM)
Post-mortem examination of infected brain with Naegleri fowleri shows …
hemorrhagic necrosis, congestion, and edema of neural tissue.
Naegleri fowler’s diagnosis is made by
finding the organism (ameba) in cerebrospinal fluid
(CSF) or brain biopsies.
It has been successfully used to treat PAM.
Amphotericin B in combination with clotrimazole
these two drugs have been shown to be active against N. fowleri, both in vitro and in vivo.
azithromycin and voriconazole
What is Acanthamoeba spp. commonly associated disease and condition names
Granulomatous amebic encephalitis (GAE), Acanthamoeba keratitis
It is the shortest tapeworm (only 3 segments: immature, mature, ripe/gravid)
Acanthamoeba spp.
Human infection of Acanthamoeba spp. results in the development of a …
hydatid cyst
The release of hydatid cyst fluid may cause
anaphylactic shock.
The hydatid cyst contains …
fluid, daughter cysts, brood capsules, and hydatid sand
Acanthamoeba spp. cyst size range is
8 to 25 um
This species has a jagged edge
and a round shape.
Acanthamoeba spp.
Acanthamoeba spp. trophozoites has a …
prominent “thorn-like” appendages (acanthopodia)
This species has prominent “thorn-like” appendages (acanthopodia)
Acanthamoeba spp.
Acanthamoeba spp. often migrate via
hematogenous spread
What kind of species infection is not associated with water but rather with contaminated saline.
Acanthamoeba spp.
Acanthamoeba spp. infection is not associated with water but rather with
contaminated saline
Pathogenesis and clinical manifestation of Acanthamoeba spp.
Granulomatous amebic encephalitis (GAE) and Acanthamoeba Keratitis
It is generally related to the destruction of brain tissue and the associated meningeal irritation.
Granulomatous amebic encephalitis
Acanthamoeba keratitis is diagnosed by
Epithelial biopsy or corneal scrapings
Suspected corneal nscrapings may be cultured on non nutrient agar plates seeded with what kind of
gram-negative bacteria
viable strain of E. coli
Acanthamoeba keratitis medications …
ketoconazole, itraconazole, miconazole, propamidine
isethianate, and rifampin.
For granulomatous amebic encephalitis suitable medication …
sulfamethazine
Acanthamoeba keratitis prevention and control
avoid using homemade nonsterile saline solutions
