Internal Parasites Internal Parasites Lab Lab INAG 120 – Equine Health INAG 120 – Equine Health Management Management November 16, 2011 November 16, 2011
Mar 31, 2015
Internal Parasites Internal Parasites Lab Lab
INAG 120 – Equine Health ManagementINAG 120 – Equine Health Management
November 16, 2011November 16, 2011
Performing Fecal Egg Performing Fecal Egg ID/Count ID/Count
Fecal egg counts are useful for: Fecal egg counts are useful for: Routine monitoring of parasite Routine monitoring of parasite
status status Identification of infected horses for Identification of infected horses for
targeted treatment targeted treatment Investigation of the parasite status Investigation of the parasite status
of a new horseof a new horse Investigation of colic and weight Investigation of colic and weight
loss loss
Benefits of Fecal Egg Benefits of Fecal Egg ID/CountID/Count
If parasites known, targeted deworming If parasites known, targeted deworming can be donecan be done Lowers costLowers cost Less chemicals used in horse’s bodyLess chemicals used in horse’s body
Horses with heavy parasite burdens can Horses with heavy parasite burdens can be treated before they suffer from a be treated before they suffer from a parasite associated diseaseparasite associated disease
Efficacy of worm control programs can Efficacy of worm control programs can be monitoredbe monitored
Performing Fecal Egg Performing Fecal Egg ID/CountID/Count
Limitations of testLimitations of test Does not detect immature or Does not detect immature or
encysted stages of strongyle encysted stages of strongyle parasites parasites
Does not discriminate between large Does not discriminate between large and small strongylesand small strongyles
Tapeworms often do not appear Tapeworms often do not appear Results not well correlated with Results not well correlated with
total parasite burdentotal parasite burden
Types of TestsTypes of Tests
Direct Flotation MethodDirect Flotation Method QualitativeQualitative Shows what kind of eggs are presentShows what kind of eggs are present
Fecal Egg Count Reduction Test Fecal Egg Count Reduction Test (FECRT)(FECRT) Also known as McMaster MethodAlso known as McMaster Method QuantitativeQuantitative Shows how many eggs are present in one Shows how many eggs are present in one
gram of feces (EPG)gram of feces (EPG)
Performing Fecal Count Performing Fecal Count TestsTests
SuppliesSupplies NeededNeeded Fresh fecesFresh feces Fecal flotation solutionFecal flotation solution StirrerStirrer Cheese clothCheese cloth Transfer pipette to syringeTransfer pipette to syringe Fecal egg count kitFecal egg count kit 100X microscope100X microscope
Performing Fecal Performing Fecal Count TestCount TestStep by Step ProcedureStep by Step Procedure Obtain fresh sample of feces, free Obtain fresh sample of feces, free
of shavings or other debrisof shavings or other debris Add flotation solution to line A of Add flotation solution to line A of
vial provided by the kitvial provided by the kit Add subsample of fresh feces to Add subsample of fresh feces to
bring volume up to Line B of vialbring volume up to Line B of vial Using stirrer, stir/mix thoroughly Using stirrer, stir/mix thoroughly
for 20-30 secondsfor 20-30 seconds
Performing Fecal Count Performing Fecal Count TestTest
Filter solution through a cheese cloth Filter solution through a cheese cloth into a new vial to remove large fecal into a new vial to remove large fecal particlesparticles
Immediately draw up sample from vial Immediately draw up sample from vial into syringe or transfer pipetteinto syringe or transfer pipette
Place transfer pipette tip at the edge of Place transfer pipette tip at the edge of the slide and discharge sufficient sample the slide and discharge sufficient sample between the upper and lower slides to between the upper and lower slides to fill the chamber. fill the chamber.
Repeat steps to fill the second chamber Repeat steps to fill the second chamber
Performing Fecal Count Performing Fecal Count TestsTests
Place slide on microscope stagePlace slide on microscope stage View slide under 100x magnificationView slide under 100x magnification Focus on the slide’s grid lines. The eggs Focus on the slide’s grid lines. The eggs
will have floated to the top of the will have floated to the top of the chamber in effect sticking to the chamber in effect sticking to the underside of the top slideunderside of the top slide
Starting from the outside corner, count Starting from the outside corner, count all eggs inside each grid utilizing grid all eggs inside each grid utilizing grid lines in an orderly fashion (from left to lines in an orderly fashion (from left to right). right).
Do not count eggs outside of the grid linesDo not count eggs outside of the grid lines
Slide GridlinesSlide Gridlines
Performing Fecal TestPerforming Fecal Test
Performing Fecal TestPerforming Fecal Test
CalculationCalculation
Record the number of eggs in each of Record the number of eggs in each of the grids:the grids:
Grid 1: _________________ eggsGrid 1: _________________ eggs Grid 2: _________________ eggsGrid 2: _________________ eggs
Calculate eggs per gram feces (EPG):Calculate eggs per gram feces (EPG): Grid 1 eggs + Grid 2 eggs = ____________ Grid 1 eggs + Grid 2 eggs = ____________
eggseggs Sum x 25 = ______________ eggs per gramSum x 25 = ______________ eggs per gram
Deciphering the Egg Deciphering the Egg CountsCounts
Infestation Infestation levellevel
Fecal Fecal Eggs/GramEggs/Gram
MildMild < 200< 200
ModerateModerate 200-500200-500
SevereSevere > 500> 500
StrongylesStrongyles
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.
AscaridsAscarids
Round with thick outer layer
PinwormsPinworms
This egg has a thicker eggshell with a plug on one end, is often flattened on one side, and already contains a developing larva.
TapewormsTapeworms
D-shaped
Strongyles
TapewormsPinworms
Ascarids