murrain (n.)

early 14c., morein, "disease or plague among people or animals or both," from Anglo-French moryn, Old French moraine "pestilence" (12c.), probably from mourir "to die," from Latin mori "to die," from PIE root *mer- "to rub away, harm" (also "to die" and forming words referring to death and to beings subject to death). After c. 1600 used exclusively of domestic animals (especially cattle).