Lecture 08 - Blastocystis and Giardia

Question 1

What are the three forms of Blastocystis

Answer 1

vacuolated form, granular form and amoeba form

Question 2

What is the lifecycle of blastcystis

Answer 2

conjugation
progeny development in cellular central body
release of daughter cells
binary fission

Question 3

How can reproduction occur in blastcystis

Answer 3

binary fission, budding, schizogony, sporulation

Question 4

What is the pathogenesis and symptomology of blastcystis

Answer 4

mechanisms are unknown

presents as diarrhea with cramps, bloating, vomiting
rare fever

Question 5

What is the epidemiology of blastcystis

Answer 5

higher in developing countries

Question 6

What are sources of transmission of blastcystis

Answer 6

poor hygeine and contaminated food/water

Question 7

How do you diagnose blastcystis

Answer 7

stool microscopy and cultivation on Jones medium

Question 8

What is giardiasis

Answer 8

a major diarrheal disease found throughout the world more common in children

Question 9

What causes giardiasis

Answer 9

a flagellate protozoan called Giardia intestinalis

Question 10

What is the trophozoite form of giardia

Answer 10

exists and replicates in the human small intestine (invasive form)

Question 11

What is the cyst form of giardia

Answer 11

passed into the environment (infective form)

Question 12

What is the morphology of the trophozoite of giardia

Answer 12

a rigid cytoskeleton composed of microtubules and microribbons as well as an axostyle – a sheet of microtubules arising from the bases of flagella, projecting beyond
the end of the cell, flexible, and also involved in movement

Question 13

How do trophozoites attach to the intestine

Answer 13

via sucking disks

Question 14

What are the parabasal body of giardia

Answer 14

an enigmatic microtubule structure of unknown
function that often forms the “crooked smile” in Giardia images

Question 15

What are the features of giardia cysts

Answer 15

contain organisms have under gone nuclear replication but BEFORE
cytokinesis (splitting of cell) = 4 nuclei

Environmentally hardy and double layered

Question 16

What is the pathogenesis of giardia

Answer 16

damage to the brush border epithelium, altered enzyme activity, enterotoxins, immunologic reactions, overgrowth of enteric bacterial flora

Question 17

What is the result of giardia infection

Answer 17

malabsorption of sugars (eg, xylose, disaccharides), fats, and
fat-soluble vitamins (eg, vitamins A and E), weight loss and diarrhea

Question 18

Where do giardia revert to the cyst form

Answer 18

if they move into the large intestine

Question 19

How is giardia transmitted

Answer 19

person-to-person, water-borne, food-borne, vernereal transmission

Question 20

Who are high risk groups for giardia

Answer 20

Children, travelers, immunocompromised individuals, men who have sex with men

Question 21

What are the symptoms of acute giardia

Answer 21

diarrhea, malaise, foul smelling fatty stools, cramps and bloating, nausea, weight loss, vomiting, fever, constipation

Question 22

What are the symptoms of chronic giardiasis

Answer 22

loose stools, foul smelling fatty stools, profound weight loss, malabsorption, fatigue, depression, cramping and bloating, burping and flatulence

Question 23

How to diagnose giardia

Answer 23

direct visualization of trophozoites/cysts
direct fluorescent antibody assay
enzyme immunoassay

Question 24

What is the string test procedure

Answer 24

patient swallows a capsule
containing gelatin and tightly
wound string.
After 5h, the string is removed from
the patient and wet mount of the
adherent material is carried out.
Can also make a permanent
smear.