By John Byrd, DVM
Our goal here is to explain how the test offered on Horsemen’s Laboratory’s website for tapeworms was evaluated for accuracy in diagnosing tapeworms in horses.
Dr. Nielsen states that increased knowledge is needed to assist in the interpretation of presently available diagnostic techniques for infection by the tapeworm Anoplocephala perfoliate in horses.
A client has asked how the test Horsemen’s Laboratory uses to detect tapeworm eggs in horses tested to determine whether the results were accurate. In order to answer this question, I first contacted Dr. Martin K. Nielsen who was one of the authors of the book Handbook of Equine Parasite Control, where I first read about the test. He emailed me a copy of 2 articles that described how the test was evaluated. The first article was published in 1992 in the VETERINARY RECORD by Dr. C. J. Proudman and Dr. G. B. Edwards (Validation of a centrifugation/flotation technique for the diagnosis of equine cestodiasis (tapeworms).
These 2 veterinarians were at the Department of Veterinary Clinical Science University of Liverpool. The second article entitled, Interpretation of serum antibody response to Anoplocephals perfoliata (most common tapeworm in horses) in relation to parasite burden and faecal egg count was published in EQUINE VETERINARY JOURNAL in 2007. This article was written by L. N. Kjaer, M. M. Lungholt, M. K. Nielsen, S. N. Olsen, and C. Maddox-Hyttel.
Dr. Nielsen’s research group went to a slaughterhouse in Europe and collected samples of blood, stool, tissue, intestine content, and tapeworms when present. They then took these samples back to their lab and analyzed them. They applied statistical analysis to the data and came up with the following finding.
What they found was that when there were less than 20 tapeworms present in the intestine of the horse there was generally very little damage done to the intestine wall (very little pathology present). They also found that the fecal egg counting technique they were using, when there were 20 or more tapeworms present, was 90% accurate at predicting which horses were positive for tapeworms. These findings were very similar to the findings that Dr. Proudman’s group found.
In conclusion after talking with Dr. Nielsen and discussing the technique he describes in the book he and Dr. Reinmeyer wrote, Handbook of Equine Parasite Control, Horsemen’s Laboratory decided to offer the test to our clients because there does not seem to be anything better at diagnosing tapeworms in horses.