Protozoa Identification and Morphological Features

Flashcards covering the diagnostic identification stages and morphological features of Protozoa including Entamoeba, Giardia, Plasmodium, and Trypanosoma species.

Entamoeba histolytica Trophozoite

Characterized by an irregular shape, a nucleus with a central karyosome, ingested RBCs, and chromatin on the inner surface of the nuclear membrane.

Entamoeba histolytica Cyst

A round shape possessing one to four nuclei, a central karyosome, and a chromatoid body.

Entamoeba coli Trophozoite

Characterized by an irregular shape, a single nucleus with a peripheral karyosome, and irregular chromatin on the inner surface of the nuclear membrane.

Entamoeba coli Cyst

A round shape containing five nuclei (or more than four), a peripheral karyosome, and irregular chromatin on the inner surface of the nuclear membrane.

Giardia lamblia Trophozoite

A pear-shaped organism featuring two nuclei, a large central karyosome, a medium body, an axostyle, and flagella.

Giardia lamblia Cyst

An oval shape containing two or three nuclei with a large central karyosome, a medium body, and an axostyle, but lacking flagella.

Balantidium coli Trophozoite

An oval-shaped, ciliated parasite with a cytostome and two nuclei: a kidney-shaped macro nucleus and a micro nucleus.

Balantidium coli Cyst

A round shape featuring a cyst wall/membrane (cilia) and a large, kidney-shaped macro nucleus.

Trichomonas vaginalis Trophozoite

Possesses a large single nucleus in the anterior end, a basal body, and flagella.

Isospora belli immature Oocyst

An oval shape with a large nucleus located in the center.

Cryptosporidium parvum mature Oocyst

A round shape containing four sporozoites.

Toxoplasma gondii Tachyzoite

A crescent or "banana shape" featuring a large nucleus in the anterior end, a tapered anterior end, and a blunt posterior end.

Toxoplasma gondii Tissue cyst (bradyzoite)

A round shape found in brain tissue containing a cyst filled with a large group of bradyzoites.

Plasmodium falciparum Gametocyte

Typically displays a banana shape or crescent shape.

Plasmodium falciparum Schizont

Found in an infected RBC of normal size; the schizont contains more than 24 merozoites.

Plasmodium falciparum Ring form trophozoite

Infected RBC is the same size as normal; characterized by multiple infections (more than one parasite per RBC), two chromatin dots, and a peripheral "Bear Dove" form.

Plasmodium malariae Trophozoite

The infected RBC is normal size or smaller, and the trophozoite presents in a band shape.

Plasmodium malariae Gametocytes

Infected RBC is the same size or smaller than normal; the gametocytes usually fill 2/3 of the RBC.

Plasmodium malariae schizont

Infected RBC is normal size or smaller; the schizont contains less than 12 merozoites.

Plasmodium vivax Adult trophozoite

A round-shaped parasite within an infected RBC that is larger than a normal RBC.

Plasmodium vivax schizont

Round shape in an enlarged infected RBC; the schizont contains more than 12 and less than 24 merozoites.

Plasmodium vivax gametocytes

Round shape in an enlarged infected RBC; the gametocytes fill the host cell.

Plasmodium ovale trophozoite

Oval shape with ameboid chromatin, found within an infected RBC that is larger than normal.

Trypanosoma brucei Trypomastigote

Characterized by an S-shape.

Trypanosoma cruzi Trypomastigote

Characterized by a C-shape.

Trypanosoma cruzi Amastigote

Oval shape found in muscle, containing a kinetoplast and a nucleus, with no flagella.

Leishmania spp Promastigote

Features a kinetoplast in the anterior end, flagella, and a nucleus.

Leishmania spp Amastigote

Oval-shaped parasite with a large nucleus and kinetoplast, found within a macrophage.