Everyone knows about mad cow disease and rabies the many different diseases the farm animals and pets we carry around with us have developed but do free animals with little contact with humans also get diseased alot? we humans gets sick between 2-3 times per year. (average) i have seen pets go years without getting sick. why are we sick more often? are we too clean? do we clean of so much bacteria that our immune system dont get enough practice or something? im no scientist, but i would like to know the answer to that one.