The Blood Curse was a mysterious plague that plunged numerous Cainites into madness before destroying them between the years of 1997 and 1999. The disease especially ravaged the cities of Berlin and Atlanta. Its results can be compared only to the great plague epidemics of the Dark Ages. A possible vector was a virus artificially bred by the Sabbat. It was conquered in a way as yet unknown by Owain ap Ieuan.
Encyclopaedia Vampirica, p. 35