Newcastle disease is a viral disease of domestic poultry and wild birds characterised by gastrointestinal, respiratory and neurological signs. Infection of chickens with Newcastle disease can take a number of clinical forms, depending upon the virulence of the particular strain of virus, ranging from inapparent to rapidly fatal. Because of its highly infectious nature and the potentially severe impact of virulent Newcastle disease on flock performance and mortality, it is one of the most feared of poultry diseases.
Newcastle disease was first identified in Australia in the 1930s, when two disease outbreaks caused by an introduced virus were controlled by slaughtering infected stock. In 1966, a non-virulent strain of Newcastle disease virus, designated ‘V4’, was isolated in Queensland and, subsequently, evidence of infection with non-virulent Newcastle disease viruses was reported from other Australian states. Hence, from 1966 to 1998, all isolates of Newcastle disease virus detected in Australia were non-virulent and the Australian poultry industry therefore remained free of virulent Newcastle disease (ND) from 1932 until 1998. Between 1998 and 2000, however, there were a number of outbreaks of virulent ND in the Sydney basin, Mangrove Mountain and Tamworth areas in New South Wales (NSW), followed by further outbreaks in Meredith in Victoria and again in western Sydney in 2002. All these outbreaks were believed to have been caused by a virulent virus that had evolved, in Australia, from a local, avirulent strain of the virus. All of these outbreaks were brought under control through slaughter out or depopulation and decontamination of the affected flocks.
In response to these outbreaks, in 2002 Government and industry jointly developed a National Newcastle Disease Management Plan to provide for a national approach to the long-term management of Newcastle disease in Australia. A key element of this Plan was the compulsory vaccination of all commercial domestic poultry flocks across Australia, according to nationally agreed standard operating procedures. Over the last few years, the Plan has been revised to allow for staged withdrawal from compulsary vaccination in low risk regions and flocks. For further information regarding the legislation in place across Australia through which this requirement is enforced, and the vaccination procedures that must be followed, please contact your State or Territory Department of Primary Industries or Agriculture.
Since the adoption of the National Management Plan, the implementation of vaccination and other measures, such as enhanced biosecurity practices, across the Australian poultry industry has to date prevented the re-emergence of Newcastle disease in Australia.