04 - Giardia Flashcards
1
Q
A
2
Q
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3
Q
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4
Q
(Giardia)
(Location in Hosts)
- Where do they live?
- How do they stay there?
A
- small intestine
- adhere to intestinal mucosa
5
Q
(Host Range)
A
6
Q
(Description of Trophozoites)
- How many flagella? how arranged?
- 12-15 X 8-10 microns
- pyriform (tear drop shaped) - bilaterally symmetrical
- ventral adhesive disc
- dorsal surface is convex
- 2 slender rods… called what?
A
- 8; arranged in pairs and 2 median bodies
- ventrocaudal flagellar grooves (axostyle)
7
Q
(Description of Cyst)
- 12X6 microns
- How many nuclei? median bodies? axonemes?
A
- 2 to 4, 2 to 4, 1 to 2
8
Q
Giardia
A
troph on right
cyst on left
9
Q
(Giardia Feeding Habits)
- How does it attach to host’s gut epithelium?
- Feeds primarily how?
- Obtains nutrients how?
A
- ventral sucker disc
- pinocytosis (absorbs through surface)
- contact digestion
10
Q
(Life Cycle)
- Trophozoites Live where?
- Dehydration in colon causes trophozoites to do what?
- then what happens?
- then what happens?
A
- upper small intestine
- encyst
- syts pass out in feces and are consumed by another host
- escyst and begin life cycle anew
11
Q
(Epidemiology)
- surface water
- What is the source?
- Is there an increase in infection with animal contact?
- Higher incidence associated with day cares
- human outbreaks associated with failure of water tx/sanitation
A
- any critter shedding cysts
- no (unlike Cryptosporidium)
12
Q
(Pathogenesis)
- main clinical sign?
- humans also get what?
A
- diarrhea
- flatulence and abdominal pain
13
Q
(Clinical Singns)
- Acute Signs?
- Chronic?
A
- foul-smelling diarrhea, mucus/greasy, flatulence, hematochezia (bloody stool) is rare
- intermittent diarrhea, weight loss, poor growth, poor appetite
14
Q
(Why is Diagnosis Difficult)
- how big?
- cysts do not float well in regular salt or sugar solutions… so use what?
- only shed intermittently… should collect how many succesive defecation?
A
- small size
- ZnSO4 (this will be on exam)
- 3
15
Q
(Diagnosis)
- obtain and test fecal samples on how many consectutive defecations/days?
- Find cyst or trophozoite in feces…
severe diarrhea is mostly what?
direct smear… see what?
- Cysts best detected how?
- stain with what to better visualize?
A
- 3
- trophozoite
“falling leaf” motion
- ZnSO4 centrigual flotation
- Lugol’s iodine
(other ways to do this are pictured)