amoebas Flashcards
The most important feature that separates amebas from the other groups of unicellular Protozoa is
the means by which they move.
Amoebas are equipped with the ability to extend their cytoplasm in the form
of pseudopods (false feet), which allows them move within their environment.
Trophozoites
the form that feeds, multiplies, and possesses pseudopods
Cysts
the nonfeeding stage characterized by a thick protective cell wall designed to protect the parasite from the harsh outside environment
The morphologic conversion from the cyst form into the trophozoite form, occurs in the ileocecal area of the intestine.
Excystation
The conversion of trophozoite to cysts.
Encystation
often show motility of the amebic trophozoites.
Saline wet preparations
The internal cytoplasmic, as well as the nuclear structures, may be more readily seen with the use of
iodine wet preparations
In the United States, amebiasis is often found in
immigrants from and people who have traveled to underdeveloped countries.
The trophozoite exhibits rapid, unidirectional, progressive movement.
Entamoeba histolytica troph
The nucleus contains a small central mass of chromatin known as a karyosome (karyosomal chromatin).
Entamoeba histolytica troph
The karyosome is surrounded by peripheral chromatin.
Entamoeba histolytica troph
Entamoeba histolytica troph no. of nuclei
1
Entamoeba histolytica trophcytoplasmic inclusion
ingested rbc
Entamoeba histolytica troph cytoplasm
finely granular
Entamoeba histolytica cyst shape
spherical to round
Entamoeba histolytica cyst no. of nuclei
1-4
Entamoeba histolytica cyst cytoplasmic inclusion
- chromatoid bars, rounded ends in young cyst
- diffused glycogen mass
Young cysts characteristically contain unorganized chromatin material that transforms into squared or round ended structures call chromatoid bars, defined as structures that contain condensed RNA material.
Entamoeba histolytica
RBCs, bacteria, yeast,
and other debris are
not found in the cyst
stage.
Entamoeba histolytica
Entamoeba histolytica lab diagnosis
- A special medium known at TYI-S- 33 supports E. histolytica in culture.
- Methods currently available include antigen tests, enzyme- linked immunosorbent assay (ELISA), indirect hemagglutination (IHA), gel diffusion precipitin (GDP), and indirect immunofluorescence (IIF).
AT ELISA IHA GDP IIF
Entamoeba histolytica infection occurs in as many as
10% of the world’s population
leading cause of parasitic deaths after only malaria.
Entamoeba histolytica
Where people tend to harbor E.
histolytica.
Locations at which human waste is used as fertilizer,
areas of poor sanitation, hospitals for the mentally ill,
prisons, and day care centers.
in E. histolytica Ingestion of the infective stage, the cyst,
occurs through hand-to-mouth contamination and food or water contamination, unprotected sex. Improperly treated water supplies
___ may also serve as vectors (living carriers responsible for transmitting parasites from infected hosts uninfected hosts) of E. histolytica by depositing infective cysts on unprotected food.
Flies and cockroaches
is the only known pathogenic intestinal ameba.
Entamoeba histolytica
Patients infected with E. histolytica who exhibit symptoms often suffer from
amebic colitis
amebic colitis is defined as
an intestinal infection caused by the presence of amebas exhibiting symptoms.
Amebic dysentery
condition characterized by blood and mucus in the stool.
in E. histolytica, The formation of
an abscess in the right lobe of the liver and trophozoite extension through the diaphragm, causing amebic pneumonitis, may occur.
In addition to the liver, E. histolytica has been known to
migrate to and infect other organs, including the lung, pericardium, spleen, skin, and brain.
Men become infected with penile amebiasis after experiencing
unprotected sex with a woman who has vaginal amebiasis.
Entamoeba histolytica treatment
- Paromomycin
- Diloxanide furoate (Furamide)
- Metronidazole (Flagyl)
The trophozoite exhibits nonprogressive motility.
Entamoeba hartmanni
Cytoplasm of __does not contain ingested red blood cells.
E. hartmanni
presence of ingested bacteria
E. hartmanni
Spherical cysts may have one, two, three, or four nuclei.
E. hartmanni
Young cysts have diffuse glycogen mass and round-ended chromatoid bars, similar to those seen in E. histolytica.
E. hartmanni
Lab diagnosis of E. hartmanni
- Stool examination
* It is important to note that the size ranges of E. histolytica and E. hartmanni overlap.
The geographic distribution of E. hartmanni is
cosmopolitan.
in E. hartmanni ingestion of infected cysts present in contaminated food or water accounts for the
transmission
Typically asymptomatic.
E. hartmanni
It is generally considered a nonpathogen and treatment is usually not indicated.
E. hartmanni
In unstained preparations, the karyosome and surrounding peripheral chromatin appear as refractile structures.
Entamoeba coli
Motility of E. coli
blunt pseudopods
Cytoplasmic inclusion of E. coli
ingested bacteria, other food particles
karyosome of E. coli
large,irregular shape, eccentric
Cytoplasmic inclusion of E. coli
vacoule containing bacteria
no. of nuclei of E. coli cyst
1-8
Cytoplasmic inclusion of E. coli cyst
- Thin chromatoid bars with pointed to splintered ends in young cysts
- Diffuse glycogen mass in young cysts, may displace nuclei (often seen in cysts with two nuclei) to opposite ends of the cyst
E. coli is found
worldwide. In addition to warm climates, E. coli also occurs in cold climates.
- Geographic areas that have poor hygiene and sanitation practices.
- E. coli is transmitted through the ingestion of the infected cyst through contaminated food or drink.
E. coli
polecki treatment
- Metronidazole
* Diloxanide furoate
