Epidemiology and diagnosis of anoplocephala perfoliata in horses from Southern Alberta, Canada

Abstract

The cestode Anoplocephala perfoliata is known to cause fatal colic in horses. The epidemiology of the cestode has rarely been evaluated in Canada. I detected A. perfoliata eggs in 4-18% of over 1000 faecal samples collected over 2 years. Worm intensity ranged from 1 to >1000 worms. Pastured horses were infected more often than non-pastured horses, especially in western Alberta, likely reflecting their higher rates of exposure to mite intermediate hosts. In a comparison of diagnostic techniques, fecal egg counts were the least accurate. Western blot analysis had the highest sensitivity to detect antibodies to the cestode (100%), but had lower specificity. A serological enzyme-linked immunosorbent assay (ELISA) had a lower sensitivity (70%) for detection of antibodies than described in previous studies. A coproantigen ELISA had 74% sensitivity and 92% specificity, and a positive correlation was found between antigen concentration and cestode intensity. The latter is important because it implicates the utility of this method for accurate clinical diagnosis and epidemiological studies.