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Flashcards in Module 2 Deck (46)
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1

Protozoa (trophozoite phase)

- actively motile, feeding stage
- motility is progressive and directional OR slow and random
- possess a single nucleus (except D. fragilis & G. lamblia)

2

microscopic features of trophozoite phase

- extension of pseudopodia (for movement)
- single nucleus with small central karyosome
- cytoplasm is finely granular

3

Protozoa (cyst stage)

- inactive stage, dormant stage
- can serve as stage of reproductive division
- may contain 1-8 nuclei

4

microscopic features of cyst phase

- enveloped with smooth outer membrane
- more than one nucleus
- reproductive replication as each nucleus forms an individual trophozoite upon excystation
- glycogen vacuole visible during early encystation
- can see chromatoidal bars

5

Classes of Protozoa

- Protozoa
- Flagellates
- Cilliates
- Coccidia

6

Protozoa class

- trophozoites are motile via extrusion of pseudopodia
- bacteria, debris or food vacuoles in cytoplasm
- multinucleated cysts produced during periods of adverse environmental conditions

7

Flagellates class

- movement via production of one or more flagella
- flagella energized by a nerve center (kinetoplast)
- body of trophozoite is rigid
- one or two nuclei may be present
- organelles contained in distinct, smooth membrane

8

Cilliates class

- locomotion via delicate cilia
- cilia present on entire cell membrane
- trophozoites and cysts of Baleantidium coli are large
- cytosome and macronucleus

9

Coccidia class

- small organisms
- replicate intracellularly within somatic cells
- use animals for extra-human sites of reproduction

10

Stages of protozoa life cycles

- freely motile, feeding trophozoites
- resting cysts
- asexual

11

Entamoeba histolytica (trophozoite phase)

- 15-20 microns
- single pseudopod = unidirectional motility
- cytoplasm is finely granular with ingested RBC's
- single nucleus with small central karyosome

12

Entamoeba histolytica (cyst phase)

- 12-15 microns
- never posses more than four nuclei
- nuclei contain a small central karyosome
- bead-like, even distribution of chromatin
- chromatoidal bars with rounded ends

13

Entamoeba histolytica (clinical conditions)

Non-invasive luminal infection, locally invasive disease, fulminant colitis, extraintestinal amebiasis, and pleuropulmonary spread

14

Intestinal disease

- lower abdominal pain, mild to full-blown diarrhea, malaise, weight loss
- endemic to Mexico and Central America

15

Extra-intestinal disease

liver abscess, fever, right upper quadrant paint pain, point tenderness over the liver and pleurisy with pleural effusion

16

Stains for Entameoba histolytica

iron hematoxylin or trichrome stain

17

Tests for E. histolytica

EIA, Serum antibody detection or immunodiffusion

18

Entamoeba coli (trophozoite phase)

- 20-25 microns
- vacuolated cytoplasm with bacteria, yeasts and other debris
- single nucleus with large eccentric karyosome

19

Entamoeba coli (cyst phase)

- 15-25 microns
- spherical and commonly contain eight nuclei
- karyosomes are large, eccentric and the peripheral chromatin is coarse and irregular
- "junky" cytoplasm
- chromatoidal bars have pointed ends

20

Entamoeba coli (clinical significance)

non-pathogenic

21

Entamoeba hartmanni (trophozoite phase)

- similar to E. histolytica
- 5-10 microns
- motility is less directional
- erythrocytes are not ingested

22

Entamoeba hartmanni (cyst phase)

- 6-8 microns
- chromatoidal bars with round ends

23

Endolimax nana (trophozoite phase)

- 8-10 microns
- motility is sluggish and non-directional
- single nucleus with no chromatin ring
- large karyosome

24

Endolimax nana (cyst phase)

- 6-8 microns
- spherical, ovoid or elliptical
- four nuclei surrounded by an open halo without a chromatin ring ("ball in socket")

25

E. nana (clinical significance)

non-pathogenic

26

Iodamoeba butschlii (trophozoite phase)

- 8-20 microns
- motility is sluggish and non-progressive
- single nucleus possesses a large karyosome surrounded by clear zone ("ball in socket")

27

Iodamoeba butschlii (cyst phase)

- 5-20 microns
- single nucleus with large central karyosome
- intra-cytoplasmic vacuole that stains brown

28

Naegleria fowleri

- free-living amoeba
- causes primary amoebic meningoencephalitis, diffuse meningoencephalitis and purulent leptomeningitis
- infection via swimming in polluted fresh water

29

Ancanthamoeba

- free-living amoeba
- associated with granulomatous amoebic encephalitis with hematogenous spread from skin or pulmonary sites
- commonly associated keratitis
- may be found in the absence of an inflammatory infiltrate
- transmission in those with contact lenses or by swimming in polluted water

30

Amoebae

- Acanthamoeba species (free-living species)
- Blastocystis hominis
- Endolimax nana
- Entamoeba coli
- Entamoeba hartmanni
- Entamoeba histolytica
- Iodamoeba butschlii
- Naegleria fowleri (free-living species)