Western Australia is considered a Free Zone for Johne's disease in respect of cattle, camelids, sheep and goats. A series of surveys using serological and culture tests demonstrated this status to the satisfaction of national Animal Health bodies within Australia from October 1999, and maintaining JD Freedom status is an advantage to the state in terms of trade. WA dealt with eight cases of BJD in cattle and one in an alpaca between 1952 and 1994. In 2000 the first case of OJD was found in a Cashmere goat and subsequently in 2001 a case was found in a Corriedale ram. With one exception, infection has been limited to a single animal and similarly, infection has been found in an imported animal with only one exception. The follow up work involved for in-contact animals can range from simple to complex operations. In the recent case where an infected goat was detected, follow up involved 42 properties, 19,503 animals and 7755 tests (1070 AGID, 5999 ELISA, 72 necropsies and 686 cultures, including pools) were performed. In all cases, infection has been detected by WA's policy of testing traceforward animals (and their cohorts) that have originated from infected flocks, information that may only become available after the animal has arrived in WA. In order to minimise the risk of spread, WA's policy is to destock all animals that may have been exposed and decontaminate land over a minimum of 15 months including two summers. Conditions of entry of livestock into WA have become increasingly stringent since 1994, thereby decreasing the risk of entry of infected animals. Modeling simulations have determined the probability of importing the disease, and these estimates have been used to determine changes under which livestock can move into WA. Currently the risk of importing an infected bovine into WA is estimated at one incursion every 250 years and for sheep the current risk from NSW is estimated at about once every 77-333 years.