The orange-yellow pigment of heartwater-infected angora goats

Heartwater is a highly fatal disease of ruminants in South Africa, caused by the parasite Cowdria ruminantium. A consistent pigment, associated with serum albumin, could be readily extracted from heartwater exudates and serum samples using n-butanol. The pigment gave a characteristic absorption spectrum between 400 and 500 nm which was absent in control serum samples. RP-HPLC of the isolated pigment revealed two components with absorption maxima at 440 and 460 nm and mol. wts of 558 and 1239. The pigment closely resembled bilirubin and/or its conjugates when compared by HPLC.