Seasonal variation in the prevalence of equine tapeworms using coprological diagnosis during a seven-year period in Denmark

We investigated the prevalence of equine tapeworms, Anoplocephala spp., in Danish horses during a seven-year period assessed by coprological analysis. The data material included > 11,000 observations distributed over the period 2009-2015, and four major geographic regions in Denmark representing sandy soils and clayey moraine soils, respectively. This allowed us to test for possible differences between regions (or soil types) and seasons. For a sub-set of the data (about 1200 observations) age of horses was also known, and it was shown that prevalence was highest in the age group 1-5 years and then declined with age. We observed no significant difference in the prevalence of Anoplocephala spp. across the geographic regions suggesting that risk of infection was largely the same irrespective the soil types included in the study. Autumn was the season with highest prevalence. However, seasonality was not very marked, and our results show that egg-producing Anoplocephala spp. are found in Danish horses year-round.