Stool testing (Method)

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This counting technique is simple, clean and has good sensitivity even at very light infections of 5-25 worms.

If we all use this technique the only variation will be our different diets, medication, time of day, drinking habits etc.

Simple video demonstration

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Add 1g of fresh Poo to a Fecalyzer

1. Take your scales and a fecalyzer to the toilet.
2. Weigh the fecalyzer (about 9.7-10.7 grams).
3. Poo into a cup or wad of toilet tissue.
4. Extract the green cage from the fecalyzer and plunge the end into the poo.
5. A clean plunge with no dags is about 1gram.
6. Return the green cage to the fecalyzer and weigh. Adjust until you have 1 gram of poo.

Note: Try and use fresh poo as we don't know the impact of using old poo.

Preparing the Fecalyzer

1. In your work area place your Fecalyzer on several sheets of newspaper (somewhere where spills are easy to clean up. Laundry?).
2. Follow the fecalyzer instructions:
   1. Snap the green cage right down.
   2. Fill up to the mark (about 7 ml) with float solution (see Fecalyzer instructions).
   3. Twist the cage fully back and forward slowly 15 times to break up the poo and release the eggs.
   4. Use your dropper to overfill the fecalyzer to the top so a meniscus forms (about another 7 ml).
3. Drop a 22 x 22 mm coverslip on top of the meniscus and let it sit for 20 mins.

Note: Ensure volume of float solution is exactly the same on each analysis. Make sure you have a standardised method for preparation of the float solution. When you turn the cage back and forth be consistent with speed and frequency each time you do it.

Preparing the Slide

1. After 20 mins the eggs have floated to the top. Lift the slip straight up (a glove is good here) and place onto a microscope slide.
2. Place the slide on your microscope stage.

Egg Counting

1. Use a 10x eyepiece and 10x objective lens.
2. Using the mechanical stage systematically move over the entire area of the cover slip.
   Start in one corner of the cover slip and step through sections using faecal debris to help you move to the next section.
   As you scan a section make small adjustments back and forward using the fine focus to catch eggs outside the current focal plane.
3. Count all eggs observed under the 22 x 22 mm coverslip.
   If you have time recount starting from the opposite corner. Note any error in count. Error will decrease as get better.
   Here a pen and paper is handy, or some use a cheap mechanical tally counter ($5 off amazon.com).

Clean up

• Tip the fecalyzer fluid down the toilet and snap the lid closed.
• Throw slides, fecalyzer, gloves etc together and wrap in paper.
  Some toilet tissue around the items will soak up any spills. If you use a paper plate you can just fold in half and staple together.
• Place in plastic bag and tie off. Do this carefully as you don't want a smelly bin.

What to Note

• Time of day (try a weekly count, same day, same time, same diet?).
• Note the faecal constancy (hard, soft, runny). When charting counts you should compare like with like.
• Note the egg count observed under the 22x22 mm cover slip.
• Note anything else you may think important (medication etc),

NB

• NA only begin to produce eggs between 4 and 6 weeks post inoculation. [1] Thereafter, the number of eggs produced increases gradually up to a maximum at about 20 weeks, so it may be best to delay stool testing until at least 12 weeks to ensure an adequate density of eggs.

• If the worms are struggling (impacted by medication or strong herbs, etc.) there will be a big drop in the egg numbers, followed by a large spike as the worms recover.

Images

• A - About 14 mls of float. Eye-dropper. Fecalyzer. On 2 paper plates to catch spills.
• B - Pop the inner green cage out of the fecalyzer and use it to scoop up 1 gram of poo using your scales.
• C - After adding 1g poo, push the green cage right down so it snaps into place and fill the fecalyzer with about 7 ml of float solution (up to the bottom of the V mark). Twist the back and forward fully about 15 times to release the eggs
• D - Add an additional 7 ml (approx.) of float to over fill the fecalyzer, forming a meniscus on top.
• E - Gently place a 22x22 mm coverslip on top and let stand for 20 mins so the eggs float up and settle under the coverslip.
• F - After 2 mins pick the slip straight up from the fecalyzer and drop onto a slide. Move to the microscope and count eggs under the slip using 100x magnification.

See also

• Stool testing (Equipment)
• Stool testing (egg counting)

the human hookworm, Necator americanus

The introduction of an infectious agent into an organism. Helminth inoculation