mud fever

noun

: a chapped inflamed condition of the skin of the legs and belly of a horse due to irritation from mud or drying resulting from washing off mud spatters and closely related or identical in nature to grease heel

: blue comb

: a mild leptospirosis that occurs chiefly in European agricultural and other workers in wet soil, is caused by infection with a spirochete of the genus Leptospira (L. interrogans) present in native field mice, and is marked by fever and headache without accompanying jaundice