TAPEWORM INFECTION IS A SIGNIFICANT RISK FACTOR FOR SPASMODIC COLIC AND ILEAL IMPACTION COLIC IN THE HORSE

The association between the equine intestinal tapeworm Anoplocephala p erfoliata and specific types of intestinal disease was investigated by matched case-control study using coprological and serological diagnos is. We have previously shown that the host IgG(T) response to 12/13 kD a antigens of A. perfoliata correlates well with infection intensity, therefore this antibody response was used to investigate the risk of c olic at different levels of parasite infection intensity. One hundred and three spasmodic colic cases with an equal number of controls match ed for age, breed and gender, and 20 heal impaction cases each with 2 similarly matched controls were obtained. Cases of spasmodic colic wer e much more likely (odds ratio = 8.0) to be associated with A. perfoli ata infection detected coprologically than controls. Serological diagn osis revealed an increasing risk of spasmodic colic with increasing in fection intensity. Calculation of an aetiological fraction suggests th at 22% of spasmodic colic cases in this study were tapeworm associated . No significant association was found between colic and strongyle egg count. Conditional logistic regression analysis demonstrated that the relationship between colic and A. perfoliata infection intensity was not confounded by strongyle egg count and there was a Linear relations hip between infection intensity and the log-odds of spasmodic colic. F or cases of deal impaction, a strong association was found between col ic and A. perfoliata as diagnosed by coprological means (odds ratio of 34.0). Serological diagnosis also revealed a strong association that increased with higher levels of infection intensity (odds ratio = 26.0 ). The aetiological fraction for the deal impaction data suggests that 81% of the deal impaction cases in this study were tapeworm associate d. This study concludes that A. perfoliata is a significant risk facto r for spasmodic colic and deal impaction colic in the horse; and that the risk of spasmodic colic increases with infection intensity.