Module 2 Flashcards
(46 cards)
1
Q
Protozoa (trophozoite phase)
A
- actively motile, feeding stage
- motility is progressive and directional OR slow and random
- possess a single nucleus (except D. fragilis & G. lamblia)
2
Q
microscopic features of trophozoite phase
A
- extension of pseudopodia (for movement)
- single nucleus with small central karyosome
- cytoplasm is finely granular
3
Q
Protozoa (cyst stage)
A
- inactive stage, dormant stage
- can serve as stage of reproductive division
- may contain 1-8 nuclei
4
Q
microscopic features of cyst phase
A
- 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
Q
Classes of Protozoa
A
- Protozoa
- Flagellates
- Cilliates
- Coccidia
6
Q
Protozoa class
A
- trophozoites are motile via extrusion of pseudopodia
- bacteria, debris or food vacuoles in cytoplasm
- multinucleated cysts produced during periods of adverse environmental conditions
7
Q
Flagellates class
A
- 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
Q
Cilliates class
A
- locomotion via delicate cilia
- cilia present on entire cell membrane
- trophozoites and cysts of Baleantidium coli are large
- cytosome and macronucleus
9
Q
Coccidia class
A
- small organisms
- replicate intracellularly within somatic cells
- use animals for extra-human sites of reproduction
10
Q
Stages of protozoa life cycles
A
- freely motile, feeding trophozoites
- resting cysts
- asexual
11
Q
Entamoeba histolytica (trophozoite phase)
A
- 15-20 microns
- single pseudopod = unidirectional motility
- cytoplasm is finely granular with ingested RBC’s
- single nucleus with small central karyosome
12
Q
Entamoeba histolytica (cyst phase)
A
- 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
Q
Entamoeba histolytica (clinical conditions)
A
Non-invasive luminal infection, locally invasive disease, fulminant colitis, extraintestinal amebiasis, and pleuropulmonary spread
14
Q
Intestinal disease
A
- lower abdominal pain, mild to full-blown diarrhea, malaise, weight loss
- endemic to Mexico and Central America
15
Q
Extra-intestinal disease
A
liver abscess, fever, right upper quadrant paint pain, point tenderness over the liver and pleurisy with pleural effusion
16
Q
Stains for Entameoba histolytica
A
iron hematoxylin or trichrome stain
17
Q
Tests for E. histolytica
A
EIA, Serum antibody detection or immunodiffusion
18
Q
Entamoeba coli (trophozoite phase)
A
- 20-25 microns
- vacuolated cytoplasm with bacteria, yeasts and other debris
- single nucleus with large eccentric karyosome
19
Q
Entamoeba coli (cyst phase)
A
- 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
Q
Entamoeba coli (clinical significance)
A
non-pathogenic
21
Q
Entamoeba hartmanni (trophozoite phase)
A
- similar to E. histolytica
- 5-10 microns
- motility is less directional
- erythrocytes are not ingested
22
Q
Entamoeba hartmanni (cyst phase)
A
- 6-8 microns
- chromatoidal bars with round ends
23
Q
Endolimax nana (trophozoite phase)
A
- 8-10 microns
- motility is sluggish and non-directional
- single nucleus with no chromatin ring
- large karyosome
24
Q
Endolimax nana (cyst phase)
A
- 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)
31
Amoebae (general features)
- trophozoite is motile via pseudopodia extension
- cyst is circular and enveloped in smooth membrane
- trophozoite has one nucleus, cyst has more than one
- trophozoite cytoplasm contains undigested material, cyst cytoplasm is smooth with a glycogen vacuole and/or chromatoidal bars
- transmission via fecal-oral route
- free-living amoeba are transmitted via contact with contaminated water/food
32
Entamoeba histolytica (complete life cycle)
Trophozoite in stool --> Immature cyst --> mature cyst --> trophozoite excystation --> trophozoite in bowel --> trophozoites in tissue
33
Blastocystis hominis
- intestinal parasite
- 5-50 microns
- blue-green staining body
- significant if > 5 per low power field
- associated with recurrent diarrhea
- irregular distribution of chromatin on outer membrane
34
Coccidia and Microsporidium
- Cryptosporidium parvum
- Cyclospora cayentaenensis
- Isospora belli
- Sarcocystis species
- Microsporidium: Enterocytozoon bieneusi, Encephalitozoon cuniculi, Encephalitozoon hellem and Nosema connori
35
Coccidia
- tissue parasite
- sexual (external intermediate host) and asexual stages
- sporogenesis and oocyst formation during sexual stage
- transmission via ingestion of contaminated food/water or ingestion of infected tissues
36
Coccidia external intermediate hosts
cat, calf or other animal
37
Cryptosporidium parvum
- small coccidian protozoa
- causes enterocolitis and diarrhea in animals
- watery diarrhea, cramping abdominal pain in immunosuppressed hosts (AIDS patients)
- diagnosis by observing oocysts (acid-fast staining, direct saline mounts and acid-fast stained fecal smears), DFA, IFA or EIA
- oocysts are very small
- sporocysts develop in brush border of intestinal epis
38
Cyclospora cayatenensis
- causes diarrheal syndrome (non-bloody), cramping abdominal pain
- transmission via ingestion of contaminated food/water
- one type of traveler's diarrhea
- diagnosis via observing oocysts (acid-fast smears, saline mounts, safranin staining, autofluoresence)
- oocysts about 2x larger than Cryptosporidium
39
Isospora belli
- diarrhea, nausea, headache, steatorrhea, etc.
- sexual and asexual stages in human intestine
- no external animal host
- oocysts are spindle-shaped, acid-fast
- immature cysts contain no or one sporocyst
- mature cysts contain two sporocysts (infective)
- increasing number of cases in AIDS population
- diagnosis by detecting oocysts in stool
40
Sarcocystis species
- found in various animals and in muscle tissue
- infection via ingestion of undercooked beef or pork contaminated with sarcocysts
- intermediate host: humans
- enter circulation and travel to various tissues (especially cardiac and skeletal muscle)
41
Microsporidium
- asexual and sexual stages
- Enteocytozoon bieneusi, Encephalitozoon species, Nosema connori, Pleistophora species, Trachipleistophora species
- diagnosis via stained tissue sections (Weber stain), stool suspensions, IFA or duodenal aspirates
- spores have dark central cross band when stained
42
Enterocytozoon bieneusi
- infects enterocytes of small intestinal epis
| - intestinal disease in AIDS patients
43
Encephalitozoon species
- infect epis and endothelial cells, fibroblasts, macrophages and other cells
- AIDS patients
- upper and lower respiratory tract infections, intestinal infections, upper and lower urinary tract infections, hepatic and gall bladder infections, CNS infections
- cuniculi and hellem: nervous system involvement, keratoconjunctivitis and chronic sinusitis
44
Nosema connori
rare isolate
45
Pleistophora species
associated myositis
46
Trachipleistophora species
multi-organ recovery in AIDS patients
