parasitology study questions

Question 1

areas of the body which can be infected by parasites

Answer 1

oral cavity, esophagus, stomach, small and large intestine

Question 2

5 different life stages seen in feces

Answer 2

eggs
oocysts
larvae
segments
adults

Question 3

2 methods of preserving a sample for later evaluation

Answer 3

refrigerate or mix with 10% formalin

Question 4

the minimum amount of fecal material needed for a fecal floatation

Answer 4

1 gram

Question 5

Under what 2 conditions would a larger sample be needed to get accurate results?

Answer 5

diarrhea or undigested hay/hair

Question 6

disadvantage of using a fecal wand to obtain a sample

Answer 6

too small of sample

Question 7

How should fecal samples be labeled

Answer 7

Owner name, pet name, date, time
collected

Question 8

If the client is collecting the sample, list 3 instructions you should give them

Answer 8

a. collect immediately after defecation
b. store in disposable container
c. approximately 1 gram needed

Question 9

precautions when handling fecal samples

Answer 9

Wear gloves and ppe, wash hands frequently

Question 10

5 things you should look for/evaluate as part of the gross exam

Answer 10

a. consistency
b. color and odor
c. presence of blood or mucous
d. foreign bodies
e. adult parasites

Question 11

Which two adult parasites may be noticed in the fecal of small animals?

Answer 11

roundworms and tapeworms

Question 12

If you skip the gross exam, what parasite might be missed? Why?

Answer 12

Tapeworm. The eggs are inside the segment and the segments don’t float. We often do break segments open in preparing the float, and if we do, we can see tapeworm ova or the dipyllidium egg packets with the ova inside.

Question 13

what does bright red blood on the feces indicate

Answer 13

bleeding in large intestine or rectum

Question 14

what does black or tarry feces indicate

Answer 14

bleeding in upper GI (stomach small
intestine)

Question 15

what does clay (off white)colored feces indicate

Answer 15

excess fat present

Question 16

2 situations where doing a direct smear would be a good idea

Answer 16

to visualize trophozoite-giardia and diarrhea

Question 17

how to perform a direct fecal smear:
a. How much feces do you put on the slide?
b. What do you mix the feces with?
c. Should you use a coverslip?
d. What microscope settings do you use?
e. How much of the smear do you look at?

Answer 17

a. Small amount
b. Water or saline
c. YES
d. 10X and 40X
e. Entire coverslip

Question 18

disadvantage of the performing only a direct fecal smear

Answer 18

not adequate because it is a small sample size and debris could be confused for parasite material

Question 19

Is the direct fecal smear a good method when looking for nematode infections?

Answer 19

NO, The sample is so small that you are likely to get a false negative result because there will be only a few ova in that amount and they may be hidden under other debris.

Question 20

parts of tapeworm that float

Answer 20

egg packets and ova

Question 21

procedure to do a simple fecal floatation

Answer 21

 Place approximately 2 g to 5 g (1-2 tsp) of feces in the paper cup.
 Add 30 mL of flotation solution.
 Use a tongue depressor to mix the feces and produce an evenly suspended emulsion.
 Pour the suspension through the metal strainer into another cup
 Pour into test tube sitting in a rack
 Fill the test tube to form a convex dome (meniscus) at the rim. Do not overfill the vial. Fresh solution can be used to form this dome
 Place a coverslip on top of the test tube.
 Allow the coverslip to remain undisturbed for 10 to 20 minutes.
 Pick the coverslip straight up and then place it on a glass slide, with the fluid side down.

Question 22

why is centrifugation method recommended

Answer 22

removes excess debris, recovers more eggs and cysts in less time

Question 23

procedure for doing the centrifugation method using a fixed head centrifuge

Answer 23

• More sensitive than simple flotation
• Recovers more eggs and cysts in less time

Question 24

What is a swinging head centrifuge? How is the procedure different if you use one?

Answer 24

A centrifuge with rotating buckets the containers that hold the samples swing
outward when spinning. You can apply the coverslip during centrifugation.

Question 25

purpose of doing a fecal sedimentation

Answer 25

Used when suspected ova are too large to be recovered with standard flotation
Fluke ova

Question 26

procedure for doing fecal sedimentation

Answer 26

 Mix 2 g to 5 g of feces in a cup with 30 mL of water.
 Strain the fecal suspension through the cheesecloth, gauze, or tea strainer into a
50-mL conical centrifuge tube. (Suspending a funnel over the tube facilitates the
filling of the tube.)
 Wash the sample with water until the tube is filled.
 Allow the tube to sit undisturbed for 15 to 30 minutes.
 Decant the supernatant off, and then resuspend the sediment in water.
 Repeat Steps 4 and 5 two more times.
 Decant the supernatant without disturbing the sediment.
 Use a pipette to mix the sediment, and then transfer an aliquot to a slide.
 Place a coverslip over the sediment, and systematically examine the slide with
100× magnification.
 Repeat Steps 8 and 9 until all sediment has been examined.

Question 27

When would we use cellophane tape to prepare a sample?

Answer 27

To gather pinworm and tapeworm segments

Question 28

Baermann technique

Answer 28

• Used to recover larvae from fecal samples
• Requires the construction of a Baermann apparatus
• Large funnel, tubing, and collection tube

Question 29

What stage of the parasite life cycle is the Baermann technique used to find?

Answer 29

larvae

Question 30

how to do the Baermann technique

Answer 30

1. Construct a Baermann apparatus. Put 30 g to 50 g of feces on top of the cheesecloth or Kimwipes, and fill the funnel with warm water (not hot) to a level above the fecal sample.
2. Allow the apparatus to remain undisturbed for a minimum of 1 hour and up to 24 hours.
3. Collect the fluid in the rubber tubing (or the stem of the glass), and transfer it to a Petri dish or a centrifuge tube.
4. Examine the Petri dish for larvae with the use of a stereo microscope, or
   centrifuge the solution to pellet the larvae. Remove the supernatant from the
   centrifuge tube, and then place the pellet on a microscope slide.
5. Examine the slide for larvae, and identify them. The slide can be passed over the flame of a Bunsen burner several times to kill the larvae in an extended position before identification.

Question 31

When would occult blood testing be performed on feces and what does the
test identify?

Answer 31

• Intestinal bleeding is suspected
• presence of hemoglobin

Question 32

When would a fecal culture test be run?

Answer 32

Used to differentiate parasites whose eggs or larvae are not easily distinguished by a fresh fecal sample

Question 33

Modifies McMasters technique

Answer 33

Provides an estimate of the number of eggs or oocysts per gram of feces

Question 34

When mixing fecal solution, why is it important that the specific gravity be between 1.18 and 1.20?

Answer 34

If SG is too high all the junk will float on the “thick” solution and the ova will be
hard to find. If the SG is too low, ova we want to see will be heavier than the
solution and sink to the bottom where we won’t find them.

Question 35

What objective is used when looking for ova?

Answer 35

10 X

Question 36

How are the condenser, diaphragm and rheostat set when looking for ova?

Answer 36

set for the 10 X objective; diaphragm 10 X, rheostat down, condenser stays in place

Question 37

What could happen if your lighting is too bright when you do the microscopic exam?

Answer 37

The light burns through the ova and you will not detect them

Question 38

Name at least 2 different solutions used for fecal floatations.

Answer 38

Sodium nitrate
zinc sulfate
magnesium sulfate
sheathers solution

Question 39

3 nematodes by their common and scientific name

Answer 39

Roundworm: Toxacaris or toxacara
hookworm: Ancylostoma
Whipworm: trichuris

Question 40

What scientific family do Dipylidium and Taenia belong to?

Answer 40

cestodes

Question 41

What is dipylidium and taenia’s common name?

Answer 41

tapeworm

Question 42

how is dipylidium and taenia transmitted to dogs and cats

Answer 42

Intermediate host Dipylidium-flea
taenia-rabbit, mouse

Question 43

scientific name of the coccidia found in dogs and cats?

Answer 43

isospora

Question 44

is isospora a nematode, cestode, or protozoan?

Answer 44

protozoan

Question 45

What is the proper term for the “egg” of isospora?

Answer 45

oocyst

Question 46

biggest parasite ova we will learn this semester

Answer 46

dipylidium

Question 47

smallest parasite ova we will learn this semester

Answer 47

coccidia

Question 48

second smallest parasite ova we will learn this semester

Answer 48

taenia

Question 49

embryonated

Answer 49

Developed into an embryo, the egg is passed hatches and reinfects within hours (whipworm)

Question 50

Nematodes

Answer 50

hookworm, roundworm, whipworm

Question 51

Cestodes

Answer 51

Dipylidium, taenia

Question 52

Protozoa

Answer 52

coccidia (isospora)