Progress in national control and assurance programs for ovine Johne's disease in Australia

Since the detection of ovine Johne's disease in Australia in 1980, 578 floc ks have been diagnosed as infected, with 442 of these still infected. The d isease was initially believed to be confined to the central tablelands area of NSW, but has subsequently been shown to be more widely distributed. She ep strains of M. paratuberculosis are known to infect sheep and goats in so uth-eastern Australia. Although sheep strains have recently been identified in some cattle in Australia, epidemiological evidence to date supports the distinction between ovine Johne's disease, caused by sheep strains in shee p and goats, and bovine Johne's disease, caused by cattle strains in cattle , goats and alpaca, as a basis for control and eradication strategies. Four national initiatives to control and better understand OJD are outlined. Th e Australian Johne's Disease Market Assurance Program for sheep was launche d in May 1997. By December 1998, 548 flocks had achieved an assessed negati ve status. Three flocks assigned a flock status have subsequently been foun d to be infected. National standards for State control of Johne's disease t hrough zoning, movement controls and procedures in infected and suspect flo cks have also been developed. In addition, a $40.1 m National Ovine Johne's Disease Control and Evaluation Program was agreed to in August 1998, and i s currently being implemented. It is jointly funded by National and State i ndustries, and Commonwealth and State governments. Its objectives are to de liver, through research and surveillance, a solid basis for a future decisi on on the most appropriate course for dealing with OJD and to maintain cont rol of OJD nationally. (C) 2000 Elsevier Science B.V. All rights reserved.