Updated Guidance for Tapeworm Control Act now to prevent resistance to tapeworm treatments

Updated Guidance for Tapeworm Control

Updated Guidance for Tapeworm Control

02 November 2023

Positive EquiSal Results and Resistance

Horse owners are being urged to act now to prevent wormer resistance to tapeworm treatments. The advisory comes after recently published research found a lack of efficacy to both praziquantel and pyrantel, our only licenced treatments for equine tapeworm (Nielsen 2023).

In response to this worrying development, Austin Davis Biologics, who developed the EquiSal saliva test for tapeworm, have issued updated guidance on the use of the test with the aim of putting a bigger emphasis on management to break the lifecycle of this parasite and reducing the reliance on chemicals.

EquiSal Tapeworm testing following a Borderline or Moderate/High Result:

The innovative EquiSal test is a saliva based ELISA that measures antibody levels that the horse produces to any tapeworm present. It gives a serum score with a recommendation on whether any treatment is required. Following a borderline or moderate/high result and subsequent treatment, a retest is recommended to check efficacy. This was previously recommended after 8 weeks, but the guidance has now changed to perform an EquiSal retest 12 weeks after treatment.

What to do if EquiSal results are repeatedly positive

If saliva scores remain high at a retest from 12 weeks onwards, it indicates that ongoing transmission of tapeworm is occurring. There are a number of steps to take to reduce tapeworm infection. 

  • Improve pasture management wherever possible - Top Tips
  • A further worming treatment for tapeworm should be considered by your prescriber where appropriate to mitigate further contamination of grazing with tapeworm eggs, looking to alternate chemicals between the two licensed actives.
  • All co-grazing horses should be assessed with EquiSal in case other horses are increasing parasite risk and acting as a continued source of tapeworm eggs.

⚠️ If saliva scores are persistently high despite the above measures, especially in a higher proportion of horses and where pasture management is deemed appropriate, anthelmintic resistance should now be considered a possibility.

Click the link below for further information


For more information on this updated guidance and research use the links below:




Lightbody, K.L., Davis, P.J., Austin, C.J., 2016. Validation of a novel saliva-based ELISA test for diagnosing tapeworm burden in horses. Vet. Clin. Path. 45: 335-46.

Matthews, J.B., Peczak, N., Engeham, S., 2023. An update on the latest developments in testing for equine helminths, In Practice, Under review.

Nielsen, M.K., 2023. Apparent treatment failure of praziquantel and pyrantel pamoate against anoplocephalid tapeworms. Int J Parasitol Drugs Drug Resist. 22;96-101.