Lab 1 - fecal floats

Question 1

In a fecal float, material separates based on what?

Answer 1

Specific gravity

Question 2

For eggs to float in fluid, they must have a ______ specific gravity than the fluid.

Answer 2

Lower

Question 3

How much space should you leave at the top of your vial when filling a fecal float before centrifugation?

Answer 3

About 1/8 inch

Question 4

True or False:

Different sizes of eggs can be located in different focal planes when doing a microscopic examination.

Answer 4

TRUE

Question 5

List the characteristics used to distinguish parasites from pseudoparasites.

Answer 5

Symmetry

Regular shell

Same size and shape

Shell may have special structures

Internal structures do not completely fill the shell

Color

Question 6

You find an adult nematode in a fecal float? Should you assume it is a parasite?

Answer 6

Not necessarily.

Free-living adult nematodes can crawl inside old stool samples. This is why it is important to always use a fresh sample.

Question 7

Parasite or pseudoparasite? Why?

Answer 7

Pseudoparasite (pollen grain)

Interior structures completely fill the shell. No discernable cellular material inside.

Question 8

I found an adult nematode in my fecal! Fire the ivermectin cannons, captain!

Answer 8

Slow down there, Charlie. This could be a pseudoparasite, especially if this is an old stool sample that has been sitting outside. Get a fresh sample and check again.

Question 9

Identify the objects in this picture marked with the red arrow and black arrow (parasite or pseudoparasite)?

Answer 9

Black arrow: pseudoparasite

Red arrow: parasite

Question 10

Parasite or pseudoparasite?

Answer 10

Pseudoparasite (pollen granule)

Question 11

Parasite?

Answer 11

Lol nope.

Probably a hair. Move your microscope focus up and down to check for jagged edges.

Question 12

Parasite or pseudoparasite?

Answer 12

Pseudoparasite

It may be tempting to call this a cestode because of the hook-like structures within the shell. However, the irregular shape and jagged edges sugges that this is not an egg.

Question 13

Parasites! Parasites everywhere!

Answer 13

Calm down, bro.

This is the non-pathogenic yeast Saccharomycopis guttulatus, a common finding in rabbits and occasionally in dogs.

Question 14

Identify the objects pictured here.

Answer 14

These are free-living mites. We can tell that they are not parasites because they lack structures on their limbs for attaching to the host (hooks, suckers, etc.)

Their eggs can be misleading if found in the stool. Look for their large size, and be sure to focus up and down to look for arthropod limbs within the egg.

Question 15

Identify this egg type.

Answer 15

Ascarid.

Note the round shape and thick, pitted shell. The center contains a single unsegmented cell that almost fills the entire shell.

Question 16

Identify these egg types.

Answer 16

Strongylid.

Note the ellipsoid shape and the morula-stage embryo within the shell.

Question 17

How do hookworms (strongylids) most commonly infect their hosts?

Answer 17

Skin penetration from larvae in the environment

Transmammary transmission from hypobiotic larvae.

Question 18

Identify this egg type.

Answer 18

Whip worm

Note the smooth shell, bipolar plugs, and symmetry when a line is drawn through the plugs. Worm is in 1-cell stage when laid.

Question 19

What kind of life cycle do whip worms (enoplids) have?

Answer 19

Direct

Question 20

Identify the egg type.

Answer 20

Isospora/Cystoisospora (Coccidian)

Note the small size, smooth shell, and single-celled sporont.

Question 21

How would you classify Isospora (i.e. what larger taxon do they fit into)?

Answer 21

Protozoa

Apicomplexa

Coccidia

Question 22

What kind of life cycle do enteric coccidians have?

Answer 22

Direct

Fecal-oral transmission