[Elizabeth_Zeibig]_Clinical_Parasitology__A_Practi(z-lib.org)

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CHAPTER 3 The Amebas
CASE STUDY 3-2
UNDER THE MICROSCOPE—cont’d
Questions for Consideration
1. What classification of parasites you suspect? (Objective
3-10B)
2. State the key differential characteristics that will distinguish
the parasites in this group. (Objective 3-10A)
3. Given the gross appearance of this specimen, what morphologic
form would you suspect to find? Does the
diagram demonstrate that form? (Objective 3-10B)
4. What key structure (other than the nucleus) is seen in
the cytoplasm of this organism? (Objectives 3-10A)
5. What organism (genus and species) and morphologic
form do you suspect? Substantiate your answer by
describing the key differential factors used to reach your
conclusion. (Objectives 3-10A, 3-10B)
6. Could this organism be the cause of the symptoms
described? (Objectives 3-10C)
7. In this sample, are other morphologic forms of this parasite
possible? If so, name the form(s) and their typical
characteristics. If not, why not? (Objectives 3-10A,
3-10I)
COMPARISON DRAWINGS
Intestinal Amebic Trophozoites Found in Stool
FIGURE 3-2A. Entamoeba histolytica trophozoite
FIGURE 3-7. Entamoeba hartmanni trophozoite
Size range: 8-65 m
Average size: 12-25 m
Size range: 5-15 m
Average size: 8-12 m
FIGURE 3-9A. Entamoeba coli trophozoite
FIGURE 3-12. Entamoeba polecki trophozoite
Size range: 12-55 m
Average size: 18-27 m
Size range: 8-25 m
Average size: 12-20 m