MAP is also found in ground beef, in the usa ground meat is usually made from culled cows,at least the bulk kind.
Anyway Japan imports a lot of meat for hamburger from Australia and
New Zealand, could this be the reason crohns increased while domestic
herds in Japan had low MAP.
MAP was a new disease first found in cows 1895,timelines with IBD fit well.
Being exposed to just the antigen or DNA may be enough to cause a problem,may
not even need to harbor live MAP,once antibodies are present.
Old Mike
LINK