Lecture 08 - Blastocystis and Giardia Flashcards
What are the three forms of Blastocystis
vacuolated form, granular form and amoeba form
What is the lifecycle of blastcystis
conjugation
progeny development in cellular central body
release of daughter cells
binary fission
How can reproduction occur in blastcystis
binary fission, budding, schizogony, sporulation
What is the pathogenesis and symptomology of blastcystis
mechanisms are unknown
presents as diarrhea with cramps, bloating, vomiting
rare fever
What is the epidemiology of blastcystis
higher in developing countries
What are sources of transmission of blastcystis
poor hygeine and contaminated food/water
How do you diagnose blastcystis
stool microscopy and cultivation on Jones medium
What is giardiasis
a major diarrheal disease found throughout the world more common in children
What causes giardiasis
a flagellate protozoan called Giardia intestinalis
What is the trophozoite form of giardia
exists and replicates in the human small intestine (invasive form)
What is the cyst form of giardia
passed into the environment (infective form)
What is the morphology of the trophozoite of giardia
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
How do trophozoites attach to the intestine
via sucking disks
What are the parabasal body of giardia
an enigmatic microtubule structure of unknown
function that often forms the “crooked smile” in Giardia images
What are the features of giardia cysts
contain organisms have under gone nuclear replication but BEFORE
cytokinesis (splitting of cell) = 4 nuclei
Environmentally hardy and double layered
What is the pathogenesis of giardia
damage to the brush border epithelium, altered enzyme activity, enterotoxins, immunologic reactions, overgrowth of enteric bacterial flora
What is the result of giardia infection
malabsorption of sugars (eg, xylose, disaccharides), fats, and
fat-soluble vitamins (eg, vitamins A and E), weight loss and diarrhea
Where do giardia revert to the cyst form
if they move into the large intestine
How is giardia transmitted
person-to-person, water-borne, food-borne, vernereal transmission
Who are high risk groups for giardia
Children, travelers, immunocompromised individuals, men who have sex with men
What are the symptoms of acute giardia
diarrhea, malaise, foul smelling fatty stools, cramps and bloating, nausea, weight loss, vomiting, fever, constipation
What are the symptoms of chronic giardiasis
loose stools, foul smelling fatty stools, profound weight loss, malabsorption, fatigue, depression, cramping and bloating, burping and flatulence
How to diagnose giardia
direct visualization of trophozoites/cysts
direct fluorescent antibody assay
enzyme immunoassay
What is the string test procedure
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.
