PROTOZOAAMOEBA

Protozoa:The protozoa are a diverse group of unicellular,

eukaryotic organisms. Many have evolved structural

features (organelles) that mimic the organs of

multicellular organisms. Reproduction is generally by

mitotic binary fission, although in some protozoal

species, sexual (meiotic) reproduction with several

variations occurs as well. Only a few of the many tens

of thousands of protozoan species are pathogenic for

humans.

Clinically important protozoa:Many of these protozoa have both a dormant,

immotile cyst stage (the infective stage) that permits

survival when environmental conditions are hostile,

and a motile, actively feeding and reproducing

vegetative ( trophozoite ) stage (diagnostic stage).

For convenience, the protozoa are classified according

to their mode of locomotion. The clinically relevant

protozoa are thus divided into four groups.

Classification of protozoa:Either by mode of locomotion:

Or by site whereinfection occurs :

AMOEBA:Can be either free living or parasitic.

Parasitic Amoeba: the parasitic is either

pathogenic: Entamoeba histolytica, or non-

pathogenic: Entamoeba coli, Iodamoeba

butschlii, Endolimax nana.

Pathogenic free living amoeba: Naegleria and

Acanthamoeba sp.

Entamoeba histolytica:We can see 2 stages : Cyst, trophozoite.

Cyst: define cell wall, small, from 1-4 nuclei,

the karyosome is in the center of the nucleus.

Trophozoite: start to motion, change its cell

wall to elongated, have pseudopodia, still

small, with 1 nuclei contain also karyosome in

the center.

Glass slides for E.histolyticaTrophozoiate Trophozoite

Entamoeba histolytica Cyst Cyst

Entamoeba coliAlso with 2 stages: cyst and trophozoite.

Cyst: larger than E.histolytica, with 4-8 nuclei, if 4

there is no confusion with E.histolytica because it’s

bigger and the karyosome is eccentric.

Trophozoite: same psuedopodia shape but larger

than E.histolytica, nuclei with eccentric karyosome,

other things such as ingested particles or RBC’s and

glycogen mass are not clear.

Entamoeba coliCyst Trophozoite

Endolimax nana

Very small in size, smaller than E.histolytica .

With 4 nuclei seen as a holes inside the cyst.

Endolimax nana

Iodamoeba butschlii

Cyst small in size but larger than E. nana

may be seen as an oval or ovoid shape have 1

large nucleus with glycogen mass, some time

it may seen dark or as a hole with central

large karyosome.

Iodamoeba butschlii

Free living amoeba: Acanthamoeba

Naeglaria: