Fig. 3

Clinical allergy scores in adult Icelandic horses during the first two years of natural exposure to Culicoides midges. a) Sixteen horses were exported from Iceland to the US in the winter (February) of year 1 and were all kept in the same environment with natural Culicoides exposure during the summer until the end of year 2. The severity of clinical allergy was evaluated by clinical allergy scoring. In the summer of year 2, nine horses became allergic while seven horses remained non-allergic. The graphs show means and standard errors of the monthly allergy scores. The dotted line shows the established cut-off value of the allergy scoring system. b) Comparison of the average monthly low and high temperatures in the environment of the horses during the first and second year of Culicoides exposure revealed similar temperature curves in both years