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Flashcards in parasitology lab exam Deck (20)
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1

which genera of parasites can be detected and identified by examination of a peripheral blood smear?

plasmodium
trypanosoma
loa
brugid

2

what are the four components of the procedure for the laboratory examination of a stool specimen for ova and parasites?

macro-exam direct
micro exam- concentration, procedure, permanent stain smear

3

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

4

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

5

name several artifacts that can be found in ova and parasite preparations

WBC
RBC
yeast
epithelial cells
plant/meat fibers
charcot-leyden crystals

6

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

7

how soon after collection should a semi-solid or liquid stool be examined?

within 30 minutes of passage

8

how soon after collection should a formed stool be examined?

within the same day

9

if a formed stool cannot be examined on the day of collection, what steps should be taken?

place it in a preservative and refrigerate

10

what stage of a protozoan (cyst or troph) is most likely to be seen in a liquid stool?

troph

11

what stage of protozoan is most likely to be seen in a formed stool?

cyst

12

what fixative should be used with a liquid stool?

PVA- polyvynal alcohol

13

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

14

what fixative should be used with a formed stool?

10% formelin

15

name several specimens other than stools that might be examined for ova and parasites

sputum
blood
urine
CSF
duodenal aspirates
perianal swabs

16

what are Charcot-Leyden crystals?

spindle shaped artifacts

17

what is the significance of the charcot-leyden crystals

E. histolytica

18

what are charcot-leyden crystals thought to be composed of?

eosinophil granules

19

name several species of protozoa that have "emerged" as significant pathogens in recent years due to the spread of AIDS

toxoplasma
Pneumocytitis carinii
cryptococcus

20

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