Increasing trade liberalisation, globalisation and international transportation of people and commodities have increased the potential for disease incursion, both plant and animal, in countries like Australia. While a comparatively strict quarantine regime and geographic isolation provide substantial protection in Australia, disease incursions are not uncommon. In recent years, there have been several exotic disease outbreaks including wheat stripe rust, bacterial blight of cotton, sugar cane ratoon stunt, potato cyst nematodes, karnal bunt, grapevine leaf rust, papaya fruit fly, Newcastle disease in poultry flocks, and Ovine Johne’s Disease (OJD) in sheep. Recent attention on the incursion of plant diseases, followed the outbreak of black sigatoka, a banana leaf disease, in the Tully district of North Queensland in 2001, and citrus canker, a highly contagious bacterial disease for citrus fruits, in the Central Highlands region of Queensland in 2004.