Fecal Examination Using The Baermannization Method
Below is description of how to test a fecal sample using Baermannization Method. The Baermannization method is used for the extraction of live larval stages of nematode parasites from the feces.
- Place a sieve in a custard dish or other similar container.
- Spread about one gram of feces on a piece of tissue paper and place it into the sieve
- Place warm* water in the dish until it just covers the feces. Be careful not to disrupt the feces.
- Allow mixture to sit for one hour**
- Lift off sieve
- Pour liquid into a 50 ml centrifuge tube.
- Let sit for 20 minutes
- Using a Pasteur pipette, remove a drop of sediment at the bottom of the tube and place it on a microscope slide for examination. Be careful not to resuspend the sediment before you take a sample from it.
* This procedure makes use of two characteristics of parasitic larval nematode behavior. First, the warmer it is, the more active the larva will be (however, you do not want to over heat them! - 37 to 40oC is the upper limit). Second, Most parasitic larval nematodes are poor swimmers.
Therefore, the following events take place when the sieve is placed in the water. The larvae will move around in a random fashion and within time, some of them will migrate through the tissue paper and fall into the water. Because the larvae can't swim, they sink to the bottom of the dish and accumulate there.
** The longer you wait the more larvae will accumulate at the bottom of the dish, but with time the fecal sample breaks down and begins to pass through the paper tissue leading to an accumulation of sediment along with the larvae.
