1. Internal Parasites Lab
INAG 120 – Equine Health Management
November 16, 2011

2. Performing Fecal Egg ID/Count
Fecal egg counts are useful for:
Routine monitoring of parasite status
Identification of infected horses for targeted treatment
Investigation of the parasite status of a new horse
Investigation of colic and weight loss

3. Benefits of Fecal Egg ID/Count
If parasites known, targeted deworming can be done
Lowers cost
Less chemicals used in horse’s body
Horses with heavy parasite burdens can be treated before they suffer from a parasite associated disease
Efficacy of worm control programs can be monitored 

4. Performing Fecal Egg ID/Count
Limitations of test
Does not detect immature or encysted stages of strongyle parasites
Does not discriminate between large and small strongyles
Tapeworms often do not appear
Results not well correlated with total parasite burden

5. Types of Tests Direct Flotation Method
Qualitative
Shows what kind of eggs are present
Fecal Egg Count Reduction Test (FECRT)
Also known as McMaster Method
Quantitative
Shows how many eggs are present in one gram of feces (EPG)

6. Performing Fecal Count Tests
Supplies Needed
Fresh feces
Fecal flotation solution
Stirrer
Cheese cloth
Transfer pipette to syringe
Fecal egg count kit
100X microscope

7. Performing Fecal Count Test Step by Step Procedure
Obtain fresh sample of feces, free of shavings or other debris
Add flotation solution to line A of vial provided by the kit
Add subsample of fresh feces to bring volume up to Line B of vial
Using stirrer, stir/mix thoroughly for seconds

8. Performing Fecal Count Test
Filter solution through a cheese cloth into a new vial to remove large fecal particles
Immediately draw up sample from vial into syringe or transfer pipette
Place transfer pipette tip at the edge of the slide and discharge sufficient sample between the upper and lower slides to fill the chamber.
Repeat steps to fill the second chamber

9. Performing Fecal Count Tests
Place slide on microscope stage
View slide under 100x magnification
Focus on the slide’s grid lines. The eggs will have floated to the top of the chamber in effect sticking to the underside of the top slide
Starting from the outside corner, count all eggs inside each grid utilizing grid lines in an orderly fashion (from left to right).
Do not count eggs outside of the grid lines

10. Slide Gridlines

11. Performing Fecal Test

12. Performing Fecal Test

13. Calculation Record the number of eggs in each of the grids:
Grid 1: _________________ eggs
Grid 2: _________________ eggs
Calculate eggs per gram feces (EPG):
Grid 1 eggs + Grid 2 eggs = ____________ eggs
Sum x 25 = ______________ eggs per gram

14. Deciphering the Egg Counts
Infestation level
Fecal Eggs/Gram
Mild
< 200
Moderate
Severe
> 500

15. Strongyles
Small strongyle eggs (cyathostomes) have a characteristic strongylid appearance, meaning they are oval and about 80 by 50 microns, have a thin complete eggshell, and contain a developing morula.

16. Ascarids
Round with thick outer layer

17. Pinworms
This egg has a thicker eggshell with a plug on one end, is often flattened on one side, and already contains a developing larva.

18. Tapeworms
D-shaped

19. Strongyles
Ascarids
Pinworms
Tapeworms