Worming for tapeworm - save wormers for when they are really needed

How do you know if your horse has a tapeworm burden that needs treating? 
Horse tapeworm burdens are usually ‘silent’ infections. You can’t tell by looking at a horse whether they have a burden and, it is not until tapeworm numbers are high enough to cause significant gut inflammation and blockages, that the horse will suffer either acute or low grade recurring colic symptoms.

The horse tapeworm, Anoplocephala perfoliata, predominantly attaches to the ileocaecal junction in the gut which is a narrow section between the small intestine and the caecum, so it is no surprise that large burdens can cause health problems.

Diagnosing tapeworm infections in horses has been difficult until recently, as tapeworms are not reliably detected by standard worm egg counts (WEC) due to the way in which they release eggs. However, saliva or blood antibody tests have been shown to be reliable and accurate*.

Why not just worm for tapeworm?

This is a common question as it is obviously easier to routinely worm horses. But it is increasingly important to avoid overuse of worming drugs. Horse worms are becoming resistant to several drugs used in this country which is a major problem because once resistance spreads, our drugs will no longer control worm infections and we will begin to see worm-related health problems emerging.

EquiSal® Tapeworm testing over the last 3 years has shown that only a quarter of horses in the UK required treatment. This is a big reduction in wormers being used to effectively control tapeworm burdens in horses. 

Saliva samples can be easily collected by horse owners using
the specially designed swab provided in the EquiSal® saliva
collection kit.

Research study recently published by Equine Veterinary Journal

A worm control programme using the EquiSal® Tapeworm saliva test has been proven to control tapeworm infections and reduce the use of tapeworm wormers at Bransby Horses, a horse welfare charity. The study reports the findings from 237 horses tested with EquiSal® Tapeworm over the course of a year². Testing with EquiSal® Tapeworm reduced the use of tapeworm wormers by 86% compared to 6 monthly routine worming strategies.

The scientifically validated EquiSal® Tapeworm saliva test accurately diagnoses horses with a tapeworm infection, providing a low, borderline or moderate/high diagnosis and treatment is recommended for horses with a borderline or moderate/high result¹. In this latest study, most horses diagnosed with a tapeworm infection in the first EquiSal® Tapeworm test reduced to low in the following two tests and 168 horses (71%) remained low throughout the study and didn’t require worming for tapeworm. Importantly, the number of horses with a tapeworm infection did not increase during the study period despite the reduced amount of wormer being administered to the herds –around 15% of horses needed worming at each testing. Only seven horses needed treatment after all three EquiSal® Tapeworm tests, suggesting that some horses are more susceptible to tapeworm infections.

The patterns of infection and reinfection seen during the study highlight how important it is to regularly test with EquiSal® Tapeworm. Testing every six months will identify horses with new infections and allow worming at an early stage. This approach limits the number of eggs contaminating paddocks and reduces exposure of other horses, as well as identifying horses which are more prone to infection. By incorporating EquiSal® Tapeworm testing into worming schedules, the frequency of tapeworm treatments are reduced which will, in turn, reduce the risk of tapeworm resistance in the future. 

The EquiSal® saliva test for tapeworm 
It is easy to integrate EquiSal® Tapeworm testing into worm control programmes – simply test every six months at a time when routine worming for tapeworm is considered. Saliva samples can be easily collected by horse owners using the specially designed swab provided in the EquiSal® saliva collection kit. Once the swab has collected enough saliva, as indicated by a colour change, the swab is placed in the preservative solution and returned to the EquiSal® testing laboratory using the freepost envelope. If a horse is diagnosed with a moderate/high burden a repeat test can be carried out 2-3 months after worming to determine if an additional treatment is required.

CASE STUDY. Jack’s story – carry out testing and only use wormers when they are really needed

Jack has been with his current owner for 13 years and in the past was routinely treated for tapeworm twice a year.

After Jack’s first EquiSal Tapeworm test in 2014, it came as a shock to his owner when he was diagnosed with a moderate/high infection.

Jack was wormed and 3 months later tested with EquiSal Tapeworm when he was again diagnosed with a moderate/high burden. He received a second worming dose and was tested after a further 3 months, using both the blood test and EquiSal Tapeworm. Both tests diagnosed a borderline result and Jack received another worming dose.

EquiSal Tapeworm has since diagnosed Jack with a low burden for the last 18 months.

Jack’s story suggests that he was likely to have been reinfected between his 6 monthly routine treatments, up until his first saliva test. The additional targeted treatment he received following his subsequent saliva tests ensured Jack’s tapeworm status was finally reduced to low. As well as testing/treating for tapeworm, Jack’s owner carried out good paddock maintenance, including regular poo picking and complete removal of muck from his grazing areas.

By continuing to routinely test with EquiSal® Tapeworm, Jack’s owner is now able to monitor for new infections and only use worming drugs when they are needed.

Interestingly, Jack has had a history of colic but since his low burden diagnosis, he has been well!

Correct paddock maintenance helps prevent reinfection

The horse tapeworm requires an additional host to complete its life cycle – the oribatid mite that lives on grassland. The mite ingests tapeworm eggs from dung piles and larvae grow within the mite until the horse eats the mite while grazing. It is important to carry out routine paddock management, such as regular muck clearance, where muck is completely removed from grazing and adjacent areas, as well as field rotation and resting where possible. Routinely clearing muck from grazing areas will significantly reduce infected mite levels on paddocks and help prevent reinfection after worming.

It is also important to restrict horses’ grazing while away from home, such as at show grounds. Lastly, ensure you know your horse’s accurate weight for correctly dosing wormers as under dosing can result in persistent burdens and continuous egg shedding.

Although it can be difficult to influence management practices outside of your own field to prevent infection, it is best practice for horses in adjacent paddocks to be following the same worm control programme.

Visit www.equisal.co.uk for more information on tapeworm in horses, to see a list of stockists or order a kit online.

Article by Dr Corrine Austin, scientist and director of Austin Davis Biologics

References:

1 Lightbody KL et al. (2017) Equine Vet J. DOI: 10.1111/evj.12742

2 Lightbody, K. L. et al. (2016) Vet Clin Path, 45: 335–346