Flashcards in parasitology lab exam Deck (20)
which genera of parasites can be detected and identified by examination of a peripheral blood smear?
what are the four components of the procedure for the laboratory examination of a stool specimen for ova and parasites?
micro exam- concentration, procedure, permanent stain smear
name the two procedures commonly used for the concentration of a stool specimen and give the principle of each procedure
formelin ethyl acetate- sedimentation
zinc sulfate- flotation
why is it useful to perform the direct examination of a stool specimen using both saline and iodine?
S- motile trophs/ larvae- moving- observing helminth ova
I- observes cysts of protozoa
name several artifacts that can be found in ova and parasite preparations
what is a scotch tape preparation and for what organism is it used?
a piece of tape or out patient device pressed over the anal opening at night (right after going to bed or right before getting up in the morning) the ova stick then examine under microscope for pinworm eggs
how soon after collection should a semi-solid or liquid stool be examined?
within 30 minutes of passage
how soon after collection should a formed stool be examined?
within the same day
if a formed stool cannot be examined on the day of collection, what steps should be taken?
place it in a preservative and refrigerate
what stage of a protozoan (cyst or troph) is most likely to be seen in a liquid stool?
what stage of protozoan is most likely to be seen in a formed stool?
what fixative should be used with a liquid stool?
PVA- polyvynal alcohol
what type of container is best to use for the collection and transporting of a stool specimen?
clean and dry doesn't need to be sterile
what fixative should be used with a formed stool?
name several specimens other than stools that might be examined for ova and parasites
what are Charcot-Leyden crystals?
spindle shaped artifacts
what is the significance of the charcot-leyden crystals
what are charcot-leyden crystals thought to be composed of?
name several species of protozoa that have "emerged" as significant pathogens in recent years due to the spread of AIDS