THE OCCURRENCE OF MYCOBACTERIUM-BOVIS INFECTION IN CATTLE IN AND AROUND AN AREA SUBJECT TO EXTENSIVE BADGER (MELES-MELES) CONTROL

The occurrence of Mycobacterium bovis infection in cattle herds during the period 1966-92 in two geographically related areas in South-West England is compared. In one area comprising 104 km(2) all badgers were systematically destroyed from 1975-81, after which recolonization was allowed; in the other, comprising 116 km(2), small scale, statutory b adger removal operations were undertaken from 1975 onwards where speci fic herds were detected with M. bovis infection. In the area, with tot al clearance, no further incidents with M. bovis isolation occurred fr om 1982-92. Survival analysis and proportional hazards regression indi cated that the risk of herds being identified with infection was less once badgers had been cleared from their neighbourhood, whereas it was greater in herds with 50 or more animals, and once cattle in a herd h ad responded positively to the tuberculin skin test, even though infec tion with M. bovis was not confirmed subsequently. The study provides further evidence that badgers represent an important reservoir of M. b ovis infection for cattle and that badger control is effective in redu cing incidents of cattle infection with M. bovis if action is thorough and recolonization is prevented.