Microscopic view of
a Strongyle egg
Strongyle & ascarid eggs
|
Faecal Egg Count
This is a count of the number of strongyle eggs per gram of faeces. As this test uses the flotation method, it will also identify eggs of Parascaris equorm (Ascarid). The test is performed on a small sample (5-10 gram) of fresh droppings.
Indications
This test is useful for:
- Routine monitoring of parasite status
- Identification of infected horses for treatment targeting
- Investigation of weight loss
- Investigation of colic
- Investigation of the parasite status of a new horse
Benefits
- By identifying horses shedding large numbers of worm eggs, treatment can be targeted at these animals.
- Horses with heavy parasite burdens can be treated before they suffer from a parasite associated disease.
- Efficacy of worm control programmes can be monitored.
Limitations
- The test does not detect immature or encysted stages of strongyle parasites.
- It does not discriminate between large and small strongyles.
- Test results are not well correlated with total parasite burden.
|
Strongyle egg on the left
Tapeworm egg
on the right
|
Tapeworm Antibody test
This test measures the level of antibody to a specific tapeworm antigen. Horses with significant tapeworm burdens have elevated levels of antibody. The level of antibody gives an indication of tapeworm infection intesity. The test results are reported with a clear guide to interpretation, either low, moderate or high infection intensity.
This test is performed on serum. Either serum or whole blood samples can be submitted.
Indications
This test is useful for:
- Routine monitoring of parasite status
- Identification of infected horses for targeted treatment
- Investigation of an acute colic episode
- Investigation of recurring colic
- Investigation of the parasite status of a new horse
|
Schematic diagram of
ELISA
|
Benefits
- Tapeworms are known to be associated with certain types of colic. Identification of heavily infected horses will allow them to be treated before colic occurs.
- By identifying infected horses treatment can be targeted at these animals only.
- Efficacy of a worm control programme can be monitored.
Limitations
- The test does not accurately discriminate between non-infected horses and those with low levels of infection.
- Test results indicate a broad level of infection intensity, not an exact number of tapeworms.
|
Masterclass
|
Masterclass - Use of diagnostic tests in worm control programmes.
This section deals with the implementation of a practical worm control programme utilising information from the diagnostic tests described.
Veterinary surgeons already have an understanding of each client's individual circumstances. They are best placed to advise on worm control programmes. Critical issues are:
- Are the horses managed by one person (e.g. single owner, trainer) or are they in multiple ownership? To be most effective, all horses in the population should be included in the control programme.
- What is the age profile of the horse population? Young horses are more likely to develop high worm burdens that cause clinical disease and more likely to contaminate pasture with infective stages of intestinal parasites.
- Is there any history of parasite-associated disease? If so, which parasite?
- What is the previous worming history of the horses? Is there any indication of resistance?
- What are the pastures like? Over-stocked, heavily grazed pasture, where faeces are never removed are far more likely to result in high parasite burdens.
For some situations, an interval dosing regime is the only safe option. For many horse owners however, there are considerable advantages to a targeted worming programme.
Here is a schematic diagram illustrating how a targeted, strategic approach to worm control can be implemented:
Interval between tests
This may be 12 weeks initially, but as a pattern of infection develops this interval can often be extended to every 6 - 9 months. Tapeworm antibody test is recommended every 1-2 years.
Action on test results
It is only necessary to treat infected horses. The use of worming drugs on horses with very low levels of infection will speed up the development of drug resistance.
Encysted cyathostomins
There is currently no way of diagnosing these. It is recommended that a routine dose of a larvicidal drug is given every year at the end of the grazing season (November/December). The only product with a label claim against arrested larval stages at present is Panacur Equine Guard (five day course).
It is important to remember that pasture hygeine should be practised at the same time.
Benefits of a targeted, strategic control programme:
Cost effective
Because worming drugs are only used on horses with proven infection, the expense of treating non-infected horses is saved. Many owners who adopt this control programme find that the cost of the diagnostic tests is more than covered by savings on worming drugs.
Environmentally friendly
The environmental impact of worming drugs, avermectin drugs in particular, is a cause for concern. Residual activity in the faeces of horses after treatment will kill many insects and invertebrates that live on pasture. Non-chemical means of parasite control and the targeted use of drugs will limit this harmful effect.
Minimises the risk of resistance
The more that parasites are exposed to worming drugs, the greater the selection pressure on them to develop resistance. A targeted, strategic approach will reduce exposure to these drugs and therefore slow down the development of resistance.
All of these benefits plus the peace of mind that comes from knowing that your horse does not have a harmful worm burden!
|
The 3 key elements in an effective control programme are:
|
|
Homepage |
Intestinal Parasites |
How worms cause disease |
Methods of control |
Case studies |
Questions & Answers |
Useful Links |
|
