Study on the prevalence of equine recurrent uveitis in the Cologne-Bonn area

Worldwide, equine recurrent uveitis (ERU) ranks among the most widely sprea d and most serious eye diseases among horses, and yet there is still no doc umentation on its current prevalence among populations of living horses. Fo r this reason, the goal of this study has been to reach a conclusion about the prevalence of ERU in a horse population examined In the Cologne-Bonn ar ea. Further, tests were conducted to see if there is a connection between E RU and horse's age, colour, sex, and breed. In total, 1014 horses were exam ined, encompassing 43 breeds and types from 37 horse stocks. The eye examin ations of the horses were performed with the help of a detailed record of e xaminations, a hand ophthalmoscope and a mydriatic. Pathological changes we re detected in 279 (27.5 %) horses. Of these 279 horses, 55 (19.7 %) were a ffected in their right eyes, 41 (14.7 %) In their left eyes, and 183 (65.5 %) in both of their eyes. 77 (7.6 %) of the examined horses were diagnosed to have ERU. Of these 77 horses, 21 (27.3 %) were affected in their right e yes, 28 (36.4 %) in their left eyes, and the remaining 28 (36.4 %) in both of their eyes. A clear correlation (r = 0.983) was established between the age of a horse and the occurrence of ERU. The results of this study indicat e that among horses older than 15 years, a quarter to a third have ERU. Gel dings were significantly more often affected by ERU (p < 0.001) than mares and stallions. Between the grouped breeds and the occurrence of ERU, a sign ificant connection (p < 0.001) could be determined. The grouped "thoroughbr eds" were more rarely affected by ERU than the grouped "warmbloods" and "po nies". A statistical connection between the horses' colours and the occurre nce of ERU could not be established; yet an accumulation of ERU was observe d among black horses and dappled horses. As has been described in earlier p ublications, the results of this study confirm the connections between ERU and a horse's breed, age and sex. The diagnosed ERU prevalence of 7.6 per c ent further does not contradict the findings of literature published previo usly, where occurrences of between 0.13 per cent to 70 per cent (average 13 %) are stated.