Parasitology Intestinal Protozoa Flashcards
Defining characteristics of amoebae
Contain pseudopodia (cytoplasmic protrusions) free living, pathogenic/non-pathogenic. found in the intestinal tract and other areas. motile trophozoites may be observed in stool as well as non-parasitic structures
Defining characteristics of flagellates
Contain flagella (extensions used for movement). Genera may live in the gastro intestinal tract, genitourinary tract, blood stream, or tissues
Defining characteristics of sporozoa
Unicellular with apical complex. In the gastrointestinal tract of vertebrates throughout life (isospora, cyclospora, & cryptosporidium) and cyst forming coccidia (extra intestinal development)
Defining characteristics of microsporidia
Obligate intracellular, spore-forming parasite. Display characteristics of prokaryotes (fungi). Are acquired from the inhalation or ingestion of spores
What are the 3 key virulence factors of Entamoeba histolytica?
- amebic lectin: binds parasite to galactose-containing sugars on host cells
- amoebapores: adherence-dependent cytolysis
- cysteine protease
What are the two Entamoeba species that are microscopically indistinguishable? How can they be differentiated? Why is it important to differentiate these?
Entamoeba histolytica and Entamoeba dispar. Entamoeba histolytica may contain RBC and causes dysentery. Patients should not be treated unless they are confirmed to have Entamoeba histolytica
What is the number of nuclei and measurement of Entamoeba histolytica cysts?
Mature cysts have 4 nuclei. Cysts measure 12 to 15 µm
Describe the trophozoite of Entamoeba histolytica.
single nucleus with centrally placed karyosome. Uniformly distributed peripheral chromatin. cytoplasm has a granular or “ground glass” appearance. measure 15 - 20 µm. Ingested RBC
Describe the trophozoite of Entamoeba dispar.
single nucleus with centrally placed karyosome. Uniformly distributed peripheral chromatin. cytoplasm has a granular or “ground glass” appearance. measure 15 - 20 µm.
What is the number of nuclei and measurement of Entamoeba dispar cysts?
Mature cysts have 4 nuclei. Cysts measure 12 to 15 µm
What is the only Entamoeba species with more than four nuclei in the cyst stage?
Entamoeba coli
True or False: It is relatively easy to distinguish Iodamoeba buetschlii trophozoites from Endolimax nana trophozoites.
False
What is the only species of Entamoeba that ingests white blood cells?
Entamoeba gingivalis
What is the treatment regimen for Entamoeba coli?
none
What is the treatment regimen for Iodamoeba buetschlii
none
What are the three tests that can be used to diagnose Blastocystis hominis?
- Routine stool examination
- Antigen detection using enzyme-linked immunosorbent assays (ELISAs)
- Antibody detection using ELISA and fluorescent antibody tests
Describe the microscopic morphology of Blastocystis hominis.
Spherical to oval cyst-like structures. central body or “vacuole” surrounded by a thin rim of cytoplasm containing up to 6 nuclei
What is the number of nuclei and measurement of Entamoeba dispar cysts?
Mature cysts have 4 nuclei. Cysts measure 12 to 15
Describe Entamoeba coli trophozoites
Measure: 15-50 µm
Nucleus: single nucleus with large eccentric karyosome and course irregular peripheral chromatin
Cytoplasm: coarsely granular and vacuolated
Pseudopodia: short and blunt and movement is nondirectional