Another method for determining
the number of nematode eggs per gram of feces in order to estimate the worm
burden in an animal. The advantage of this method is it is quick as the
eggs are floated free of debris before counting, the disadvantage is you
must use a special counting chamber.
out 2 grams of feces.
the feces through a sieve into a dish containing 60 ml of ZnSO4
or saturated salt solution. Lift the sieve and hold over the dish. Push out
any remaining solution from the feces.
mixing vigorously (you may want to put the solution into a flask to prevent
spillage) take a sample of the mixture with a pipette and transfer it to
one of the chambers of the McMaster slide. Repeat the procedure and fill
the other chamber.
Counts done before and after
anthelmintic treatment allow you to monitor for drug-resistance. Counts
done between scheduled treatments allow you to monitor the worm load and
thus allow you to change the treatment schedule if necessary.
30 sec then count the total number of eggs under both of the etched areas
on the slide. Focus first on the etched lines of the grid, then go down a
tiny bit, the eggs will be floating just below the top of the chamber.
Multiply the total number of eggs in the 2 chambers by 100,
this is the eggs per gram (EPG).
volume under the etched area of each chamber is 0.15 ml (the etched area is
1 cm X 1 cm and the chamber is 0.15 cm deep) so the volume examined is 0.3
ml. This is 1/200 of 60 ml. Since you started with 2 gms of feces and then multiplied by 100, the final
result is eggs per gram of feces.
here for a video demonstration of the McMaster Egg Counting Technique
Commercial Sources of McMaster
Corporation 5004-228th Ave SE, Issaquah, WA. USA 98029, http://www.vetslides.com/
2. Focal Point, Mr. Eddy Krecek, St. Kitts, West Indies http://www.mcmaster.co.za/ email: email@example.com
3. Prof. Antanas
N0, 17-14, Vilnius LT-08412, Lithuania, Cell phone
+370-618-24502, email: firstname.lastname@example.org
4. FEC Source PO Box 2522,
Hillsboro, OR 97123 USA. (http://fecsource.com/index.html) email: email@example.com telephone:
NOTE: Since McMaster slides
are often difficult to find, these listings are being given as a service to
those looking for a source for them. This should not be taken as an
endorsement by the University of Pennsylvania.
If you want to have one of these
slides made for you, here are the particulars:
They are usually made of Glass or Plexiglass: 2
pieces (2.5 cm by 7.5 cm) with 2 etched boxes (1 cm by 1 cm) on the under side of the top piece. Some people make the
bottom piece a little wider than the top piece to make it easier to load.
The etched boxes usually have 5 additional etched lines (subdividing the
box into 6 sections) to make counting easier. The etched lines should be as
thin as possible so eggs are not hidden under them. The 2 pieces are
separated by pieces (0.15 cm thick) placed at both edges and in the center
between the etched boxes. (see photo above)