Evaluation of diagnostic techniques for Anoplocephala perfoliata in horses from Alberta, Canada

Accurate diagnosis of parasites within individual hosts remains a difficult task. Incorrect and/or inaccurate diagnosis restricts the potential for targeted treatment of individuals and limits our understanding of key epidemiological characteristics of potential pathogens of domestic stock. In this study, we compared the specificity and sensitivity of four diagnostic methods for determination of the presence and intensity of the cestode Anoplocephala perfoliata in horses. Over 400 horses from an abattoir in south-central Alberta were evaluated for the presence and number of cestodes. Thirty one horses were infected with 1 to >1000 worms. Diagnosis based upon faecal egg counts of horses with known numbers of worms was least accurate in detecting worm presence. Detection of circulating antibodies to the cestode was most sensitive using Western blot analysis (100%), but had lower specificity (87%). A serum-based ELISA had a lower sensitivity (70%) for detection of antibodies. A coproantigen ELISA had 74% sensitivity and 92% specificity, and there was a positive correlation between antigen concentration and tapeworm intensity. The coproantigen ELISA may have the potential as a diagnostic tool for determining the presence and intensity of this potentially pathogenic cestode.