About Worm Egg Counts


How safe are DIY faecal egg counts?

There are only three ways to definitely diagnose a parasitic infection:
[1]    Faecal egg count for egg laying worms
[2]    ELISA antibody blood work test for tapeworm
[3]    Gut inspection under surgery

Options 2 and 3 can only be carried out by veterinary surgeons who have chosen to specialize in equines.  Option 1 is now available on a DIY basis to any horse owner.  This is quite a contrast as the diagnosis of disease is usually only carried out by experts.  We will review how safe this is and highlight the pitfalls of DIY faecal egg counting.


What is a faecal egg count?

A sample of your horse or ponies dung is viewed under a microscope to see whether any worm eggs are present in the dung. 

What do the results mean?

The results show the number of eggs seen in the sample.  However an accurate count is not possible and so many commercial providers offer results to the closest 50 eggs per gram of dung.  The veterinary university laboratories can analyse the results to under 10 eggs per gram of dung.  The provides much more accuracy in the results.

Do they identify all worms?

They only show up the eggs from the worms that lay eggs as part of their lifecycle.  This does not include pin worm, bots and tapeworm.

Why do I need to do this test?

The worms that cause disease in our horses and ponies have developed a resistance to all of the chemical wormers that we give to them.  In a nutshell they may not be working any more.  A faecal egg count is the only way to assess whether the chemicals are working.
Only 20% of horses have worms, however over 80% are still being wormed.  Using faecal egg counts instead of wormers means that your horse or pony will only have the chemicals that they actually need.

How safe is it to stop worming?

It is very safe if a full risk assessment is taken on the pasture contamination levels and the faecal egg counts are carried out at the correct time.  However this is not something that you should even attempt to do on your own.  The interpretation of facael egg count results should only be carried out by an expert in parasitology.  Standard interpretations and recommendations are dangerous and should not be followed without checking with your vet or an independent expert such as Intelligent Worming.

Why can’t I do it myself?

If your horse or pony has a clear faecal egg count result then the standard recommendation from most commercial labs is ‘no worming needed’.  However this is not always correct.  It is possible to have a ‘false negative’.  This is when the dung sample is taken whilst there are still active chemicals in the horses system.  It is also always dangerous to stop worming foals and young horses as they can develop severe clinical symptons much quicker than adult horses.  The labs who just perform the sample analysis provide standard worming recommendations and are not specific to your individual circumstances.

What does a clear result mean?

It means that there are no active adult worm eggs in the sample of dung that you have sent for analysis.  It does not mean that your horse does not have worms!!!!  The worm life cycle includes many larvicidal stages that are not detected from faecal egg counting and there are also worms who would not show up any way.

What is the point of faecal egg counting?

Faecal egg counting is a fantastic development in the professional parasitological tool kit.  They can be used to assess whether the chemical intervals of a worming program are suppressing egg laying activity.  They can be used to detect resistance to chemical wormers and they will also detect severe parasite infections.  Veterinary recommendations are to stop blanket chemical worming as there is no need.  It is only by replacing the chemicals with faecal egg counting that our horses will remain safe.  The incorporation of this practice into your horse health care program should commence in 2010.

Do all companies and vets offer the same service?

Every test involves the analysis of dung under a microscope, however the quality of the results will vary greatly.  There is no quality control over faecal egg counting and no qualifications needed to carry out the test.  The cost of the microscope can vary from £25.00 to £3,000 such as those in the veterinary universities.  This has a huge impact on the accuracy of the result.  There is also another piece of equipment that will improve the visibility of the sample.  A centrifuge spins the dung and organic matter in the sample away from the eggs.  With a centrifuge only the eggs are left to view, without a centrifuge all grass, dung matter etc are still under the slide when viewed through the microscope.  I am certain that you can picture the difference between the quality of the two methods.

What price should I pay for faecal egg counts?

A good quality commercial egg count should cost approximately £10.00.  If you are using one of the university veterinary laboratories then the price will increase to approx £12.85 due to the superiority of equipment and training of staff.
Intelligent Worming is currently working with the University of Liverpool to bring all of the latest research and technology

To purchase a faecal egg count kit click here