Lessons learned during the successful eradication of bovine tuberculosis from Australia

Abstract

There are very few international examples of the successful eradication of bovine tuberculosis (TB, caused by infection with Mycobacterium bovis) from a national cattle population. This paper presents a brief overview of the successful TB eradication programme in Australia from 1970, with primary emphasis on lessons of international relevance that were learned from the Australian experience. The national brucellosis and tuberculosis eradication campaign ran for 27 years from 1970 to 1997 and has been followed by ongoing abattoir surveillance. Rapid progress towards eradication was made in southern Australia, but proved much more challenging in extensive pastoral areas of northern Australia. Declaration of TB freedom was made on December 31, 1997. A range of factors were critical to this success, including a compelling rationale for eradication, an agreed final outcome, industry commitment and financial support, a business model for programme planning, implementation and review, consistent and transparent technical standards underpinned by a strict regulatory regime and applied research, the critical role of abattoir surveillance, effective elimination of residual infection and objective measures of programme progress. Although direct translation of some of these experiences may not be possible, many of the lessons learned from the Australian experience may be relevant to other countries.

FIG 1:

Chronology of key events in the brucellosis and tuberculosis eradication campaign (BTEC) and related programmes. ABTBSP Australian Bovine Tuberculosis Surveillance Project, EADRA Emergency Animal Disease Response Agreement, NGSP National Granuloma Submission Program, OIE World Organisation for Animal Health, TB Tuberculosis, TFAP Tuberculosis Freedom Assurance Programme

FIG 2:

Single intradermal (caudal fold) test, which formed the basis throughout BTEC for the whole-herd test and slaughter programme. Photo: Kevin de Witte

FIG 3:

Helicopter mustering. Photo: Kevin de Witte

FIG 4:

The ‘Judas’ cow technique, which was used to locate residual animals. Photos: Kevin de Witte (a), Ron Glanville (b)

FIG 5:

In extensive pastoral areas, reactor postmortem examinations were conducted in the field. Photo: Kevin de Witte

FIG 6:

The pathway for change in herd classification, based on McGuin (1986) and the final (1995) version of the standard definitions and rules (Box 1). This figure represents the status pathway used during BTEC and should not be strictly interpreted as a hierarchy of risk. For example, depending on herd history, MN status was generally (but not always) considered to represent a lower TB risk than CF

FIG 7:

Changes in TB area classification over time during the Australian brucellosis and TB eradication campaign. Modified from BTEC progress reports number 1 (October 1975), 4 (1977-78), 7 (1980-81), 10 (June 1984) and 13 (June 1986, July 1989, December 1992). Definitions for area classification are presented in Table 1

FIG 8:

The final round of testing on the last quarantined infected property in Queensland, Australia. For further information, see Appendix B (adapted from More and Roe 2002) (available online as Supplementary Data). Photo: Rod Robertson