EquiSal Tapeworm testing is an integral part of best practice worm control programmes. The test accurately detects tapeworm infections in horses, enabling horse owners, SQPs and veterinary surgeons to tailor worming protocols to each horse's requirements. This approach reduces drug resistance risks and promotes better equine health and welfare
How To Test
Initial testing
It is advised that a horse should not undergo worming for four months prior to being tested with the EquiSal Tapeworm Test.
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Frequency of testing
It is advisable to test horses for tapeworm twice annually, with spring and autumn being the optimal times. However, testing can occur at any point throughout the year.
Testing in spring identifies horses likely to shed tapeworm eggs during the peak grazing time via the oribatid mite, which serves as an intermediate host (see 'Equine Tapeworm' page for more information).
Testing in autumn helps to detect horses that may have acquired tapeworm burdens during the grazing season, and require treatment to reduce the risk of disease such as colic. Evidence suggests that a burden of >20 tapeworms can result in damage to the intestine that can lead to clinical signs, with larger tapeworm burdens increasing the likelihood of colic.
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To reduce the selection for anthelmintic resistance in tapeworms, worming should be performed only when tapeworm test results demonstrate a need for treatment. Given that horses may host a variety of worms, results from tapeworm tests should be integrated into a comprehensive worm control programme (see below).
How To Collect a Saliva Sample
The EquiSal saliva collection swab is a registered design specifically created for horse saliva collection. The absorbent tip gathers approximately 0.5 ml of saliva, and once this amount is collected, the swab's volume indicator turns pink.
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Horses should not eat, drink, or exercise for at least 30 minutes prior to collecting a sample for EquiSal testing to ensure accurate results. It is advisable to secure the horse away from food sources, such as hay or salt licks, and could be an ideal time for a grooming session. If the horse is at pasture, simply tie it near a gate or a similar area.
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To collect a sample, use the provided saliva swab from the EquiSal kit. Insert the swab into the interdental space, rest it on the tongue, and let the horse move its tongue beneath the swab.
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After half a minute, remove the swab and check the volume indicator for a bright pink change. If the colour has not fully changed, reinsert the swab and continue until the indicator changes colour. Dry mouth conditions may prolong the sampling time; if your horse's mouth is dry, sample collection can take several minutes. Many customers express surprise at the ease of collecting saliva from their horses, even from those that are typically challenging to worm.
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After the indicator turns pink, insert the swab into the provided tube containing the preservative solution. This solution ensures that saliva samples remain stable for a minimum of three weeks at room temperature. Next, affix the provided barcode label, write the horse's name on the tube, and return the sample to the EquiSal lab using the prepaid envelope. Your veterinary surgeon, SQP or yourself will receive the results via email on the day of testing.
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Complete instructions are included in the detailed 'Instructions For Use' leaflet found in every EquiSal kit. Additionally, there is a video available that shows how to use the swab for collecting your horse's saliva. You can watch this video on YouTube at Saliva Collection Video.
Notes: Faecal egg count (FEC) tests evaluate the extent of worm egg contamination on pastures but do not provide accurate information on the internal burden levels in horses, particularly, the presence of immature (larval) worms.
Tapeworm tests can be conducted using saliva or blood samples. Small Redworm Tests are performed using blood samples. The presence of worm-specific antibodies, as detected by these tests, correlates with the levels of worm infection at certain burden thresholds.
It is essential to test all horses in a group to identify and treat those with high levels of egg shedding or elevated antibody levels. For worm control programmes targeting young horses and foals, seek guidance from a veterinary surgeon or a Suitably Qualified Person (SQP).
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Background to worm control in horses
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Intestinal worms are prevalent in horses, with the most common types being:
- Small redworms (cyathostomins)
- Tapeworms (Anoplocephala perfoliata)
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Horses become infected with worms by consuming immature worms, or larvae, while grazing. Small redworm larvae are directly ingested along with the grass, whereas tapeworm larvae are consumed within mite intermediate hosts that live on paddocks. The following diagram outlines the lifecycle of parasitic worms and the crucial factors for their management.
While worms can lead to severe illness, only horses with significant worm infections typically exhibit clinical symptoms. The majority of well-cared-for, healthy adult horses over five years-old carry low worm burdens and remain disease-free. Consequently, most adult horses (about two-thirds) do not require frequent worming treatments. This is crucial since worms can develop resistance to wormers through persistent use, allowing them to withstand the lethal effects of these medicines. Resistance is a problem across all prevalent worm species, as outlined below:
As no new wormers are being introduced to the market, control strategies cannot depend solely on these medicines. Wormers should be administered only when necessary, and worm control programmes must incorporate paddock management strategies to lower worm infection levels in the environment and diagnostic testing to determine which horses need treatment.
Management strategies
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Effective parasite control relies on management strategies that minimize contamination of worms and mites on pastures. The most effective method to reduce contamination is complete removal of dung from paddocks at least twice weekly. It is crucial not to deposit dung near paddocks, as mites infected with worms and worm larvae can travel from the dung heaps back to the grazing areas. Fresh dung should never be spread on grazing paddocks, and dung heaps must be situated far from watercourses. In the UK, harrowing paddocks for worm control is not advised.
Maintaining low stocking densities is an important component of effective worm control, with more than one acre allocated per horse being optimal. Utilizing cattle and sheep can aid in lowering infection levels on paddocks. Using these animals during the first half of the grazing season to rest the paddocks from horses is beneficial. However, it is vital to be mindful of liver fluke, as this parasite can transfer between different animals. If this is a concern, consult your veterinary surgeon.
Pasture resting can be effective without sheep or cattle because many small redworm larvae that infect paddocks in one season will die by the middle of the next summer. However, this does not apply to tapeworm larvae in mites or eggs of other worms, such as ascarids (commonly referred to as roundworm), which can survive for more than a year.
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Diagnostic testing
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Diagnostic tests that are useful for guiding worming treatment decisions include:
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- Faecal egg counts (FEC) which estimate the level of egg shedding in the dung of individuals. These tests can be used to assess shedding of eggs of small redworms and other worms such as ascaris (roundworm).
- Antibody tests that provide information on the burden of tapeworms and small redworms.
Implementing testing can significantly decrease the frequency of worming treatments. Through integration of excellent pasture management and worming treatments guided by diagnostics, substantial reductions in the usage of wormers are achievable. This approach reduces the likelihood of resistance developing within worm populations.
The relationship between management practices, diagnostic measures, wormer applications, and selection for resistance is detailed in the diagram below.​
Good worming practice
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When administering wormers to horses, it is crucial to calculate the dosage accurately based on the horse's weight to prevent accelerating resistance due to under-dosing.
It is important to use the appropriate wormer for the type of worms present. For instance, if a tapeworm infection is confirmed when there is no evidence to treat for other worms such as small redworm, a wormer that specifically targets tapeworms, such as praziquantel, should be used rather than a combination wormer or a wormer that has an effect on non tapeworm species. In this way, unnecessary resistance will be avoided.
Integrating Tapeworm Testing into Sustainable Parasite Control Programmes
For horses with a borderline or moderate/high saliva score, retesting with EquiSal 3 months post-treatment is advisable. Tapeworm-specific antibodies reduce quicker in saliva than in blood. A study has shown that over 70% of horses treated with praziquantel had antibody levels fall below the treatment threshold within 5 weeks (Lightbody et al., 2016. Vet Clin Pathol. 45:335-346). Subsequent research indicated that horses on pastures with regular dung removal or those stabled had a reduction of EquiSal saliva scores to below treatment thresholds in all cases within 12 weeks (Matthews et al., 2024. In Practice 46:34-41).
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Persistently high saliva scores upon retesting after three months suggest continued tapeworm reinfection from grazing. It is advisable to improve pasture management when possible, and consider anti-tapeworm treatment to reduce further pasture contamination with tapeworm eggs. Additionally, all horses sharing grazing areas should undergo the EquiSal Tapeworm test to determine if they are contributing to the ongoing contamination of tapeworm eggs onto the paddock.
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The graphic (below) illustrates the points in the tapeworm life cycle where reinfection risks are present, along with strategies to mitigate these risks. It is crucial for owners to avoid repetitive testing and treatment of horses without assessing management practices, as such actions may contribute to the development of wormer resistance.
Tapeworm testing following a borderline or moderate/high result: evidence based guidance
