About Parasitology
The diagnosis of intestinal helminthiasis in animals is most commonly performed indirectly by microscopy on faeces for the detection of the parasites’ eggs or cysts. This procedure involves suspending the sample in a special ‘Flotation Solution’ of an adjusted Specific Gravity (S.G. 1.20 – 1.27) which is higher than that of the eggs/cysts but lower than the other faecal debris which sink. This results in the eggs floating to the surface and which can then either be counted and/or identified by microscopy (x 100 magnification). The two types of method are described below:
Worm Egg Count Method
This method is useful for checking the worm burden of large, grazing animals (e.g. horses, cattle, sheep) which tend to have low worm burdens naturally. Animals shedding relatively large numbers of worm eggs in their faeces are at risk of loss of condition and illness and pose a threat to other animals grazing the same pasture. Worm egg counts (F.E.C.s) are also useful as part of a Faecal Egg Reduction Test to detect the efficacy of, or the resistance to, the anthelmintic in use. In general, F.E.C.s help vets and owners maintain their livestock in good health, provide financial benefits by avoiding unnecessary worming treatments and delay/avoiding anthelmintic resistance.
The McMaster Slide method of estimating the parasite load of an animal is made up of just four easy-to-understand and perform steps.
First, separate the worm eggs from a sample of the animal’s faeces using a Faecal Flotation Solution. Second, find the eggs (oocytes) using a microscope and, third, count them using the McMaster Slide. Finally, knowing both the weight of faeces sampled and the number of worm eggs counted, calculate the animal’s likely level of worm infection.
Performing the F.E.C. requires a Microscope, a McMaster Counting Slide, Flotation Solution and other small items of equipment and consumables. However, especially for those who wish to start performing their own F.E.C.s and make it easier, we have bundled all these items together in discounted Bespoke DIY Kits, three of which include a microscope and one without.
Concentration/Flotation Method
This method is more appropriate for companion and small animals (e.g. dogs, cats) where the presence of any intestinal parasite is undesirable and so no egg count is necessary.
The basic principle uses a flotation solution of special Specific Gravity in which the faecal sample is mixed and poured into a centrifuge tube. This can then be incubated vertically on the bench for up to 10-15 minutes or centrifuged ready for microscopic examination
For this method we offer either the ParaTEST ®VET kit or the StatSpin OvaTube kit which include all consumables required. Please check our Microscopes page if you require a microscope.
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