The EquiSal Test

The EquiSal Test

The EquiSal Tapeworm Test (patent pending) is a simple-to-use horse saliva test for detecting harmful tapeworm infections in horses. It was developed by family business, Austin Davis Biologics Ltd, who now provide a testing service to diagnose tapeworm burdens and recommend treatment. The EquiSal Tapeworm Test works like a blood test but, instead, uses saliva that horse owners are able to collect themselves using a specially designed saliva collection swab. The saliva swab is posted back to the laboratory in a preservative solution which keeps the sample stable for at least three weeks.

During 2012 and 2013 the research team, consisting of three experienced scientists (one of whom was an inventor of the Clear Blue pregnancy test), developed and rigorously validated this innovative test before launching the diagnostic service during April 2014.

The test measures tapeworm-specific antibodies in saliva, using a combination of three laboratory tests (called ELISAs*). Each sample is analysed under very carefully defined conditions to account for variations in saliva flow and impact of diet. The saliva samples are handled by an automated liquid handing system to ensure very high accuracy, as well as high-fidelity sample tracking throughout the test procedure. An algorithm is applied to integrate data from the three different tests to generate an EquiSal diagnosis of tapeworm burden – the saliva score.

The table below shows the results provided by the EquiSal Tapeworm test service. The test identifies horses with low burdens, borderline results or moderate/high burdens and treatment is recommended as detailed.

 

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* An average moderate/high saliva score is approximately 16, but very high scores can reach into the hundreds. Regardless of the saliva score, any horse with a borderline or moderate/high result should be treated.

 

EquiSal Tapeworm Test accuracy

The EquiSal Tapeworm Test was validated by testing saliva samples taken from horses in which the number of tapeworms present had been counted at post-mortem. In scientific terms, the EquiSal Tapeworm Test has both high sensitivity and specificity, which is important for correctly identifying horses with tapeworm burdens.

The majority of horses with one or more tapeworms at post-mortem were correctly identified by the test. The remaining few were diagnosed as being negative but these horses had burdens considered by experts to be not pathogenic (pathogenic meaning capable of producing disease), amounting to no more than 20 tapeworms. This is similar to the current guidelines for redworm faecal egg counts (FEC), where a result of less than 200 eggs/gram is not recommended for treatment.

 

This means that the EquiSal Tapeworm Test can be relied upon to:

·         correctly identify the majority of horses with a moderate/high burden

·         correctly identify all horses with pathogenic burdens

 

When data from a tapeworm blood test and the EquiSal Tapeworm test were compared, they were shown to have strong positive correlation with each other. When these tests didn’t give the same diagnosis, it was when non-pathogenic burdens were present (less than 20 tapeworms). The tapeworm blood test and EquiSal Tapeworm test were found to have the same level of accuracy at diagnosing tapeworm burdens.

Please click here to download our scientific information leaflet.

Our validation paper has been published in Veterinary Clinical Pathology. To view this online, click here.

Publication in a peer reviewed journal means that subject specialists have fully reviewed, or refereed, the research paper. The publication of the EquiSal Tapeworm validation paper therefore demonstrates quality of science, reliability of the findings and that the research is of an accepted standard. The paper details the methods we use for the EquiSal test and the full validation of the test against the blood test as well as post mortem samples when tapeworms were counted.

Independent validation

The veterinary consultant at Bransby Horses Charity carried out a small independent comparison of EquiSal Tapeworm testing versus the current serological testing which showed strong positive correlation of the test results. The Bransby Horses team has since started using EquiSal regularly and endorse the test.

 

A day in the life of an EquiSal Tapeworm test

When saliva samples arrive at the lab, the unique barcodeThe_EquiSal_Test_-_pic_1 label on each sample is scanned into the database along with the horse’s name. This information allows us to track samples throughout the testing process, as well as telling us information about the sample, such as where the kit was purchased and where the results need to be sent back to. We then remove and discard the swabs from the tubes – the remaining samples range in colour enormously, from colourless to dark green or brown, and sometimes there are particles of grass or food present.

 

The_EquiSal_Test_-_pic_2The samples are loaded onto the automated robotic liquid handling system to carry out dilutions, additions and to pipette each sample into pre-prepared ELISA* test plates. Each sample is tested twice in three different ELISA tests to give the final result. This meticulous procedure ensures the test has high accuracy and that saliva flow rate and other saliva variables do not affect the results.

 

 

 

 

The test plates are incubated with a series of differentThe_EquiSal_Test_-_pic_3 solutions, one of which results in the development of a blue colour. The test is stopped with a final solution resulting in a colour change from blue to yellow and the intensity of the yellow colour is measured. The result, which is linked to the barcode for each sample, is collected and processed.

 

The results are quality checked and verified by two experienced scientists before being emailed out to vets, SQPs and horse owners.

 

 

*ELISAs (Enzyme Linked ImmunoSorbant Assays) are common diagnostic tests used in medicine, veterinary medicine and various industries.