Introduction to Diagnostic Medical Parasitology
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  • Exercises for amoebae and flagellates
    • What parasitic stage do you observe?
      • Cyst with a thick cell wall
        • Can filaments be seen within the cyst?
          • Filaments present (cyst of flagellate)
            • What is the size and shape of the cyst?
              • Cyst pear shaped, 1 nucleus, size 5-9 µm
              • Cyst oval with thick wall, 2 – 4 nuclei, size 10-14 µm and “halo” (gap between cyst wall and cytoplasm)
          • No filaments present (cyst of amoeba)
            • How do the nuclei look like?
              • There is peripheral nuclear chromatin present
                • How is the chromatin arranged?
                  • Chromatin is fine granular, evenly distributed, Karyosome small, usually in the centre of the nucleus
                    • What is the size of the cyst?
                      • Cyst is smaller than 10 µm, 1, 2 or 4 nuclei, glycogen mass, vacuole present
                      • Cyst is larger (between 10 and 15 µm) with glycogen mass and vacuole, 1 nucleus
                      • Cyst is larger (between 10 and 15 µm) no glycogen mass and no vacuole, 2 nuclei
                      • Cyst is larger (between 10 and 15 µm) no glycogen mass and no vacuole, 4 nuclei
                  • Chromatin coarsely granular, unevenly arranged, Karyosome eccentric, cyst larger than 10 µm
                    • How many nuclei do you see?
                      • Immature cyst: with vacuole and 2 , rarely 4 nuclei
                      • Mature cyst: has no vacuole and 8 nuclei (often not all visible)
              • There is no peripheral nuclear chromatin present
                • What is the shape of the nuclei?
                  • Cyst contains 4 small nuclei with compact chromatin masses like small pin needle dots
                  • Cyst with large eccentric and half-moon refracting nucleus, large vacuole present
                  • Cyst-like, vacuole (central body), narrow rim of cytoplasma with nuclei and inclusion bodies
                  • Large cyst (50-70 µm) with big macronucleus
      • Trophozoite with 2 or more flagellae
        • How many flagellae has the parasite?
          • Trophozoite with 4 flagellae, 1 nucleus, “end spine” size: 6 – 20 µm
          • Trophozoite (pear shaped) with 4 pairs of flagellae and 2 nuclei; resembles a face
      • Trophozoite with no flagellum
        • How do the nuclei look like?
          • There is peripheral nuclear chromatin present
            • How is the chromatin arranged?
              • Chromatin coarsely granular, unevenly arranged, Karyosome eccentric, size : larger than 15 µm
              • Chromatin is fine granular, evenly distributed, Karyosome small, usually in the centre of the nucleus
                • Are red blood cells within the parasite?
                  • Red blood cells are present
                  • There are no blood cells phagocytosed
                    • What is the size of the trophozoite?
                      • Size usually under 10 µm
                      • Size larger than 10 µm
          • There is no peripheral nuclear chromatin present
            • How many nuclei can be seen?
              • One nucleus in all trophozoites
                • What is the shape of the nucleus?
                  • Nucleus with peripheral granules, fine cytoplasm, trophozoite smaller than 10 µm
                  • Nucleus refracting, trophozoite larger than 10 µm
              • Two nuclei in more than 50% of trophozoites and large chromatin mass
      • Trophozoite with cilia, ovaloid with cytostome and macronucleus