The extreme example is death by heart attack while handling them based upon PLD demyelination in about 0.04 % of goats. The point is that many other diseases and parasitoses are occurring in CL animals, not normal ones, and this difference is unaccounted for. However, CL animals should immunologically respond to other antigens in a normal manner. Nonetheless, to challenge sheep & goats with a live vaccine that will kill a few by adding PLD and spread CL to others is foolish.