Theoccurrence ofMycobacterium bovis infection incattle inand aroundanareasubject toextensive badger (Meles meles) control

SUMMARY Theoccurrence ofMycobacterium bovis infection incattle herds during theperiod 1966-92 intwogeographically related areas inSouth-West England iscompared. Inoneareacomprising 104km2allbadgers weresystematically destroyed from 1975-81, after whichrecolonization wasallowed; intheother, comprising 116kM2,small scale, statutory badger removal operations wereundertaken from 1975onwards wherespecific herds weredetected withM.bovis infection. Inthe areawithtotal clearance, nofurther incidents withM.bovis isolation occurred from1982-92. Survival analysis andproportional hazards regression indicated thattherisk ofherds being identified withinfection wasless oncebadgers hadbeen cleared fromtheir neighbourhood, whereas itwasgreater inherds with50ormore animals, andoncecattle inaherdhadresponded positively tothetuberculin skin test, eventhough infection withM.bovis wasnotconfirmed subsequently. The study provides further evidence thatbadgers represent animportant reservoir of M.bovis infection forcattle andthatbadger control iseffective inreducing incidents ofcattle infection withM.bovis ifaction isthorough andrecolonization isprevented.