Ovine Johne's Disease (OJD) was first detected in sheep in Australia in 1980. Monitoring of sheep for OJD commenced in New South Wales (NSW) abattoirs in late 1999 as part of a national program, with approximately 70% of adult sheep slaughtered monitored annually. Since 1999, OJD has spread to infect more flocks in the High (48% of direct consignments positive in 2006) and Medium Prevalence Areas (30% positive) of NSW. However around half of the sheep flocks in NSW remain in the Very Low Prevalence area (0.5% positive in 2006).

Inspection details, laboratory results and the origin of the sheep slaughtered were recorded in a Microsoft Access database. From 1999, OJD positive consignments from a single vendor (direct lines) were traced to their property of origin. In contrast, OJD negative consignments were initially only identifiable to locality and local government area.

Tracing was streamlined by the introduction of the National Livestock Identification System (NLIS) in 2002 which required sheep consignments to be accompanied by a National Vendor Declaration (NVD). Recording of the Property Identification Code (PIC) on the NVD became compulsory from January 2006. This enabled direct lines to be precisely allocated to a property, locality, local government area or OJD prevalence area.

Linking inspection details to the PIC database led to reporting of negative inspection results to producers from 2004. A list of GPS coordinates for all localities was added in 2006 which enabled accurate mapping for the first time.

Mapping provides an excellent visual communication tool that has markedly improved the capacity to review progress with the national OJD program. This has been particularly important in consultation with sheep industry representatives regarding the location of prevalence area boundaries at the regional, state and national level.

The results of monitoring from 1999 to 2006 will be presented including maps showing the changes in distribution over time.