Giardia

Question 1

Giardia characteristics

Answer 1

No mitochondria or golgi
Free living, 4 pairs of flagella
Trophite inside the body, cyst outside the body, asex or becomes cyst
Mastigonts/kinetid: any structure used for locomotion
Karymastigonts: mastigont/kinetid associated with the nucleus
Flat/pear shaped with paired nuclei (owls eyes)
Human reservoir only
Prevalent in poor sanitation, contaminated water, travelers, campers, hikers

Question 2

Giardia life cycle

Answer 2

1. Cysts can survive in cold water for months, contaminated food/water or fecal/oral introduces cyst
2. SI, excystation releases trophozites from cyst (has two each)
3. Trophizites multiply by binary fission, can be free or attach to mucosa
4. Attaches to mucosa, can block uptake of nutrients/water reabsorption, thus diarrhea, can destroy GI villi
5. Encystation occurs as parasites transit toward colon, cysts most commonly found in non-diarrhea feces
6. Cysts are infectious when passed into stool

Question 3

Giardia infection/symptoms

Answer 3

Giardiasis
1-2wk after exposure, fecal/oral, travelers
Early symptoms: flatulence, abdominal pain, N/V, weight loss
Foul smelling bulky explosive watery diarrhea, no blood in stool, no necrotic tissue
Stool often contains excessive lipids
Chronic -> malabsorption, disaccharide deficiency, lactose intolerance, B12 malabsorption

Question 4

Giardia treatment

Answer 4

Metronidazole 3x/day for 5 days
OR
Tinidazole single 2g dose