Technical Information
Tapeworm infections in horses are not reliably detected by standard worm faecal egg count methods due to the intermittent way adult worms release eggs and because many infections comprise high proportions of immature and non-gravid adult worms which do not contain eggs. Saliva or serum antibody tests have been developed and shown to be reliable and accurate in detecting equine tapeworm infection.
The Tapeworm Blood Test detects tapeworm-specific antibodies which have been shown to have strong positive correlation to tapeworm infection intensity (Spearman’s correlation, 0.78). The ELISA format includes a calibration curve to accurately generate a ‘serum score’ for each sample as well as provide a quality control for each ELISA carried out. Serum scores are categorised into ‘low’, ‘borderline’ and ‘moderate/high’ diagnoses based on the test validation and anti-tapeworm treatment is recommended for borderline and moderate/high results.
Validation of the Tapeworm Blood test (published in Veterinary Clinical Pathology)
Serum samples (139) were collected from horses at a UK abattoir. The ileocecal junction and cecum were visually examined for tapeworms and any present were counted. Samples were analysed using the Tapeworm Blood Test. The test results were compared to tapeworm numbers and the datasets were statistically analysed.
Using Mann–Whitney tests, comparison of the Low-burden group to the Moderate/High-burden group (1+ tapeworm cut-off) for the test resulted in P-values of <.0001, demonstrating a high statistically significant difference.
Area under the curve (AUC) data, from ROC curve analysis, was significantly different from 0.5 (P < .001), demonstrating that the blood test was able to differentiate between samples using either a 1+ or 20+ tapeworm cut off.
When a 1+ tapeworm cut off was assigned, 85% sensitivity and 78% specificity was obtained. Importantly, based on an in-depth analysis of the validation data, it was found that using the 1+ tapeworm burden cut-off correctly diagnosed all high burden horses (i.e. those with >20 tapeworms). While studies have shown that the severity of intestinal lesions is associated with the number of tapeworms present, it is generally accepted that the presence of 20 worms or less is not pathogenic. Reports also indicate that not only does infection intensity relate to clinical impact, but the site of attachment of the worms within the intestine, particularly the ileo-caecal junction, where even a small number of worms can result in lesions.
Uses of the Tapeworm Blood Test
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Identification of horses with tapeworm infections to inform targeted worming treatment.
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Diagnosis of horses with clinical symptoms.
Limitations
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The test does not provide exact numbers of tapeworms present, but provides a low, borderline or moderate/high diagnosis.
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Antibody levels in blood reduce over time in response to treatment so the test cannot be used to monitor anthelmintic efficacy. It has been demonstrated that blood antibody levels are not reduced to low diagnosis until at least 4 months after treatment. However, this is complicated by horses becoming reinfected or juvenile tapeworm maturing after treatment.
Testing recommendations
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It is advisable to test horses biannually, preferably during spring and autumn.
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Spring testing is crucial for identifying horses with infections which can lead to pasture contamination through the shedding of eggs during the peak activity period of the oribatid mite intermediate host.
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Autumn testing helps detect horses carrying potentially pathogenic tapeworm burdens, informing treatment decisions to reduce the risk of tapeworm-related disease such as colic.
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Where a low tapeworm risk is determined, either by consistent negative test results or after comprehensive risk assessment, it may be adequate to test annually, in spring or autumn.
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An initial test is recommended to be conducted four months following the last anthelmintic treatment for tapeworms.
Peer reviewed publications
1. Lightbody KL, Davis PJ, Austin CJ. 2016. Validation of a novel saliva-based ELISA test for diagnosing tapeworm burden in horses. Vet Clin Pathol. 45:335-46.
This paper describes the development, optimisation and validation of the EquiSal saliva test and provides a comparison of its performance against the tapeworm blood test. The results in this paper were, in part, used to establish the guidelines for using the tests for informing anti-cestode anthelmintic treatment decisions in horses.
Validation of a novel saliva‐based ELISA test for diagnosing tapeworm burden in horses
2. Lightbody KL, Matthews JB, Kemp-Symonds JG, Lambert PA, Austin CJ. 2018. Use of a saliva-based diagnostic test to identify tapeworm infection in horses in the UK. Equine Vet J. 50:213-219.
This study assessed the effectiveness of the EquiSal saliva test in detecting tapeworm infections in horses within a large equine welfare organisation. The findings indicate that, when compared to treating all animals as a group, using EquiSal significantly decreased the administration of anti-cestode anthelmintics. This highlights the value of the test in mitigating selection pressure for anthelmintic resistance.
3. Jürgenschellert L, Krücken J, Austin CJ, Lightbody KL, Bousquet E, von Samson-Himmelstjerna G. 2020. Investigations on the occurrence of tapeworm infections in German horse populations with comparison of different antibody detection methods based on saliva and serum samples. Parasit Vectors. 13:462.
This paper presents findings from a study of 48 German horse farms employing faecal egg count (FEC) testing, antibody-based assays and questionnaires to assess tapeworm infection prevalence and associated risk factors. Permanent access to pasture, large/frequently changing grazing areas and elevated strongyle egg counts were linked to an increased risk of infection. Recent praziquantel administration, the presence of foals and larger herd sizes were indicated as protective. Tapeworm prevalence was significantly higher when measured by antibody-based methods compared to standard FEC tests, highlighting the low sensitivity of the latter and supporting incorporation of antibody based tests in diagnostic protocols for tapeworm control.
4. Burcáková L, Königová A, Kuzmina TA, Austin CJ, Matthews JB, Lightbody KL, Peczak NA, Syrota Y, Várady M. 2023. Equine tapeworm (Anoplocephala spp.) infection: evaluation of saliva- and serum-based antibody detection methods and risk factor analysis in Slovak horse populations. Parasitol Res.122:3037-3052.
This study assessed the occurrence of Anoplocephala perfoliata using coprological, serum-based and saliva-based antibody detection methods, and analysed risk factors associated with infection in Slovakia. Tapeworm prevalence was significantly higher when measured by antibody-based methods compared to standard FEC tests. Analysis identified four predictors significantly influencing the detection of tapeworm: age, pasture size, anthelmintic treatment scheme and access to pasture. The findings showed that FEC tests have low sensitivity for identifying tapeworm infections, thereby reinforcing the recommendation to incorporate antibody-based diagnostics into worm control programmes.
https://pmc.ncbi.nlm.nih.gov/articles/PMC10667452/pdf/436_2023_Article_7994.pdf
5. Matthews JB, Peczak N, Lightbody KL. 2023. The Use of Innovative Diagnostics to Inform Sustainable Control of Equine Helminth Infections. Pathogens. 12(10):1233.
This review provides an overview of diagnostic tests available that facilitate evidence-based worm control in horses and discusses strategies for their effective integration to minimise anthelmintic usage and preserve the efficacy of these medications.
The Use of Innovative Diagnostics to Inform Sustainable Control of Equine Helminth Infections
6. Matthews JB, Austin CJ. 2023. Using diagnostics in supporting sustainable worm control in horses. UK Vet Equine 7:2-6.
This review discusses the use of diagnostic tests in modern worm control programmes and how to integrate these tests for effective worm control. This review includes new data on the performance of these tests in field settings.
Using diagnostics in supporting sustainable worm control in horses | UK-Vet Equine
7. Matthews JB, Peczak N, Engeham S. 2024. An update on the latest developments in testing for equine helminths. In Practice 46:34-41.
This review describes how to integrate EquiSal and the tapeworm blood test into sustainable worm control approaches for horses and includes new data on the use of EquiSal in practice.
8. Matthews JB, Lightbody KL, Peczak N, Austin CJ. 2024. An update on the use of saliva-based diagnostics for Anoplocephala perfoliata infections in horses. Equine Vet Educ. 36: 14-15.
This article reviews use of the EquiSal test since its launch in 2014 and provides a summary on long term seasonal reporting of the test and the use of the test in understanding transmission of the parasite in the field and its applicability in support anthelmintic efficacy investigations in practice.
An update on the use of saliva‐based diagnostics for Anoplocephala perfoliata infections in horses
9. Kukurić T, Erdeljan M, Matthews JB, Lightbody KL, Austin CJ, Peczak N, Uzelac A, Klun I, Simin S. 2025. A Prevalence Study on Anoplocephala spp. in Serbian Horses: Navigating Diagnostic Challenges and Understanding Infection Risks. Animals (Basel). 15:2094.
This study assessed the prevalence of infection with Anoplocephala perfoliata in Serbia and identified associated risk factors. Infection status was determined through coprological analyses and serological testing using the tapeworm blood ELISA. The overall prevalence was 38.7%, with serology identifying more positive cases than faecal egg count (FEC) methods. Risk factors for infection included high stocking density, free-roaming status and co-infection with nematodes. Conversely, lower rainfall and temperate climate were linked to a reduced risk of infection. The results demonstrated that FEC methods have lower sensitivity for detecting tapeworm infection compared to antibody-based serological tests.