Occurrence of Anoplocephala perfoliata infection in horses in Ontario, Canada and associations with colic and management practices.

The study investigates the connection between horse colic and Anoplocephala perfoliata infection in Ontario horses, along with relating management practices to the likelihood of infection. While the infection was present in many horses, its direct link to colic isn’t clear, although diet related to higher seropositivity.

Study Overview

• The research aimed to find any relationship between the risk of colic in horses and infection with the tapeworm Anoplocephala perfoliata. It also looked into how seropositivity to the infection correlated with the horses’ management practices.
• The study used a matched case-control design, one of the observational study designs whereby each case is matched with a control based on age, breed, and gender or any other confounding variables. It involved 117 pairs of horses in Ontario.

Infection Assessment

• The infection status of the horses was ascertained based on positive results from a coprological examination (an examination of fecal matter), and/or their seropositivity to a 12/13 kDa A. perfoliata secretory protein.
• It was discovered that 56% of the horses were seropositive for A. perfoliata, meaning that they showed signs of an immune response to the tapeworm. However, eggs from the tapeworm were found in fecal samples from only 6% of the horses.

Dietary Link

• Interestingly, the study found that horses that largely relied on pasture for their diet were significantly more likely to exhibit ELISA optical density levels above 0.600, suggesting a higher concentration of antibodies against the tapeworm, compared to horses that were not so reliant on pasture (odds ratio [OR]=6.38; p=0.029).
• Therefore, this finding suggests that the exposure to pasture is a significant source of A. perfoliata infection in horses, likely due to the parasite’s lifecycle involving an intermediate host commonly found in grasslands.

Colic Connection

• In a specific subset of 46 pairs of horses – where the control horses had no known history of colic – the study indicated a statistically significant negative association between the risk of colic and optical density (OD) levels ranging from >0.200-0.600 compared to OD levels ≤ 0.090 (or=0.08; p=0.017).
• Despite this, the research didn’t find any other statistical evidence suggesting a direct association between the risk of colic and A. perfoliata infection in horses. The negative association suggests a lower risk of colic with higher OD levels, however, it’s not definitive proof and further research is needed to confirm this.