[Microbiology] Re: worm count
(by juergenwiegel from gmail.com)
Tue Mar 1 21:59:58 EST 2011
Joy, you probably got good advice to prepare a stool sample to analyse for
the presence / absence of worm eggs. I assume that's what you are
interested in., If you wan to look for some worms, depending on the
involved worms (I am not a zoologist) but from worm checking in the stool of
my own children, as John already said, you do not need a microscope, at the
most a good lens if you try to specify and are curious about them. But if
you -for what ever reason-- are interested in being quantitative, you
would need for an "egg count" a litle chamber (as used for blood counts,
such as the Petroff-Hauser Chamber) which gives you a fixed volume that
you analyse using the microscope and count the eggs in that volume.from
there you multiply back to your total volume from which you take the sample
for counting. Otherwise your egg count could be off several fold. But you
also need to quantify your stool sample (use a small and cheap letter
balance) and the total volume in your glass, so that you get the number
of eggs per g of stool sample. Otherwise you cannot compare what you
"count" from one week to the other or from one to the other animal. You also
need to do at the very minimum three independent counts to get somewhat
meaningful numbers. This is probably more than you want to do, but just in
On Tue, Mar 1, 2011 at 20:07, John <yjgent from verizon.net> wrote:
> On Feb 27, 12:03 am, "Joy Young" <joyyo... from netspace.net.au> wrote:
> > I live on a farm and looking to buy a microscope to do worm count on my
> animals, I wondered if a student microscope would be satisfactory I am told
> that I require a magnification of 100 x 400. I am not familiar with
> microscopes but would be pleased to learn.
> > Joy Young
> You've already gotten good advice about the microscope, but do you
> know anything about doing a "worm count" on farm animals? First of
> all, you are not looking for worms, they would be big enough you don't
> need a scope. You will be looking for their eggs and while they are
> prolific producers of eggs, they tend to be lost in all the other
> stuff in stool. There are several processes to "clean up" the sample
> to leave it clear enough to see the eggs.
> My favorite method involves a pilsner glass, an wire egg beater and
> 4x4 gauze. Take a stool sample the size of about a walnut and mix it
> in warm tap water using the wire whisk egg beater. Pour sample into
> pilsner glass through at least 2 layers of gauze. Add more warm water
> to fill glass. Let sit for about 30 minutes. Carefully pour off
> supernatant without disturbing the sediment. Refil the glass with warm
> water and let sit for another 30 min. Repeat up to 4 times until
> supernatant is somewhat clear. Now Pour off the supernatant and draw
> up a small sample from the sediment place a drop on a slide and add a
> cover slip and observe under 100x at first and then move up to 400x if
> you see something suspicious.
> This was a method I learned from my Microbiology supervisor back in
> 1975, and i don't think it is an accepted method for clinical
> parasitology today. But it might work just fine for farm animals.
> Now the last thing is do you know what the eggs will look like when
> you do see them? You should get a book with photomicrographs and
> drawings of worms and eggs you would expect to see in your animals.
> Most of these parasitology books will also have methods of preparing
> samples for microscopy work.
> Good luck and happy hunting!
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