protozoans

e. histolytica

trophozoite 12-60 um, motile and unidirectional progressive movement and ingests RBC

e. histolytica

cyst 10-20 um, round quadrinucleated (4 nuclei) with smooth cigar-shaped chromatid

e. hartmanni

trophozoite Small, 3-12 um, non-pathogenic does not ingest RBCs

e. hartmanni

cyst 4-10 um, qudrinucleated w rod-shaped chromatoid bodies with rounded ends

e. coli

trophozoite 15-50 um, sluggish motility, coarse chromatin, eccentrically located endosome and the absence of erythrocytes in the cytoplasm, broad and blunt pseudopodia

e. coli

cyst 10-35 um, has 8 nuclei, splinter-like chromatoidal bodies(filamentous)

e. polecki

cyst Uninucleate with angular or pointed chromatoid bars

e. polecki

trophozoite 10-12 um, sluggish movement, with a small central karyosome

e. gingivalis

trophozoite 10-20 um, found in the oral cavity, ingests WBCs (esp. neutrophils) moves actively with numerous blunt pseudopodia

endolimax nana

trophozoite 5-12 um, sluggish movement w a large irregular karyosome, blunt hyaline pseudopodia

endolimax nana

cyst 5-12 um quadrinucleate, lacks peripheral colum

iodamoeba butschlii

trophozoite 9-14 um, large vesicular nucleus w a prominent central karyosome

iodamoeba butschlii

cyst 9-10 um, uninucleated with a distinctive large glycogen vacuole (stains dark brown w iodine

naegleria fowleri

trophozoite 10-35 um, when rounded usually 10-15, cytoplasm is granular and contains vacuoles, nucleus is large, with a dense karyosome and lacks peripheral chromatin

naegleria fowleri

flagellate form 10-16 um, temporary, non-feeding stage that reverts back to trophozoite

naegleria fowleri

cyst Spherical, about 7-15 um, smooth, single-layered wall with a single nucleus, not seen in brain tissue

balantidium coli

trophozoite 30-150 um long, 25-120 wide, covered w cilia, bean-shaped macronucleus, round micronucleu

balantidium coli

cyst 40-60 um, spherical to ovoid, thick double wall

giardia lamblia

trophozoite 9-12 um long, 5-15 um wide, tear-drop shaped, 4 pairs of flagella, 2 nuclei, a pair of ovoidal nuclei. Has adhesive sucking disc

giardia lamblia

cyst 8-12 um x 7-10, ovoid, 4 nuclei when mature, young cysts have 2

t. vaginalis

trophozoite 7-23 um, pyriform, 4 anterior flagella, a 5th flagellum in undulating membrane

t. hominis

trophozoite Pyriform shape 7-13 um, 5 anterior flagella and a posterior flagellum, cytostome, axostyle

t. tenax

trophozoite 5-12 um, pyriform flagellate, 4 flagella + short undulating membrane

chylomastix mesnili

trophozoite 6-10 um, spiral groove, 3 anterior flagella, boring and spiral forward movement

chylomastix mesnili

cyst Lemon-shaped or pear-shaped w knob-like protrusion

Cryptosporidium hominis

Oocyst: 4-5 um, thick-walled, contains 4 sporozoites

Cyclospora cayetanensis

Oocyst: 8-10 um, spherical, 2 sporocysts x 2 sporozoites

Cystoisospora belli

20-30 um, ovoid oocyst w 2 sporocysts x 4 sporozoites

S. hominis/ S. suihominis

Sporocyst: 15-19 x 8-10 um, 4 sporozoites

toxoplasma gondii

trophozoite 4-8 um x 2-3 um, crescent-shaped w pointed anterior and a rounded posterior end

toxoplasma gondii

cyts 10-13 um x 9-11 um, ovoid oocyst w 2 sporocysts each w 4 sporozoites

S. hominis/ S. suihominis

Banana-shaped w apical complex

Dientamoeba fragilis

trophozoite 7-12 um, 1 or 2 (rarely 3-4) rosette shaped nuclei, no peripheral chromatin, 4-6 karyosome granules, cytoplasm w vacuoles

Dientamoeba fragilis

Vacuolated form: 5-10 um, large central vacuole, 4 nuclei peripherally located

B. bovis

trophozoite 2.4 x 1.5 um

B. equi

2 x 1 um

B. bigemina

4-5 x 2-3 um

B. Caballi

3 x 2 um

Blastocystis hominis

cyst 3-10 um, 1-2 nuclei, thick electron-dense wall

Trypanosoma Cruzi

trophozoite Trypomastigotes: 16-20 um (slender), 15 um (stumpy); C, S, or U-shaped w prominent kinetoplast

Amastigotes: 1.5- 4 um, round/ovoid in tissue

T. gambiense/rhobediense

trophozoite Trypomastigotes: 14–33 µm length, 1.5–3.5 µm width; polymorphic, with undulating membrane and terminal flagellum

leishmania

Amastigotes: ovoid/rounded, intracellular in macrophages, ~2–5 µm.

Promastigotes: elongated with flagellum, extracellular in vector.

P. Falciparum

trophozoite Small delicate rings; multiple rings per RBC; appliqué (accolé) forms; Maurer’s dots; crescent-shaped gametocytes.

P. Vivax

trophozoite Enlarged RBCs; amoeboid trophozoites; Schüffner’s dots; mature schizont with 12–24 merozoites.

P. Malariae

Band-form trophozoites; schizont with 6–12 merozoites in rosette; normal-sized RBCs.

P. Ovale

trophozoite Oval/fimbriated RBCs; Schüffner’s dots; schizont with ~8 merozoites.

P. Knowlesi

trophozoite Ring stages resemble P. falciparum; late trophozoites resemble P. malariae; schizont with 16 merozoites.