Newcastle Disease Management Plan (NDMP)
Newcastle disease
Newcastle disease (ND) is a viral disease of domestic poultry and wild birds, which is characterised by gastrointestinal, respiratory and nervous signs.
The virus strains that cause ND can be categorised into three different types, based on their virulence in chickens, with most strains being either highly virulent ("velogenic") or avirulent ("lentogenic") and some falling into a smaller middle category ("mesogenic"). Velogenic strains cause severe and often fatal disease in chickens, while lentogenic strains usually cause subclinical infection or just mild respiratory signs. While the epidemiology of ND is not completely understood, it is thought that wild birds, in particular water fowl, may be the reservoir for lentogenic strains of ND virus. These viruses could become more virulent after establishing in poultry.
For detailed information on the worldwide distribution and importance of the disease, including its aetiology (classification of the causative agent), epidemiology (host species, clinical and pathological signs and modes of transmission), diagnosis, control, and public health relevance, please see the ND disease card on the website of the World Organisation for Animal Health (OIE).
Newcastle disease in Australia
Australia is free from virulent ND, but this has not always been the case.
Australia's first cases of virulent ND occurred in 1930 and 1932; both were eradicated according to a slaughter-out policy.
In 1966 an avirulent strain was identified. Evidence suggests that this strain and other avirulent strains have since spread through the poultry industry in all states. During the 1990s, strains emerged that were associated with mild disease and some were found to be genetically similar to virulent ND viruses.
In September 1998, a virulent ND virus emerged on a mixed layer and broiler farm at Deans Park, Western Sydney, New South Wales. Genetic sequencing showed that this virus had originated from an avirulent ND virus of Australian origin, and that it was genetically different from ND viruses that occur overseas. In April 1999, a further outbreak of ND occurred at Mangrove Mountain on the New South Wales Central Coast. In early 2000, there were cases in Western Sydney and Tamworth, New South Wales. The Tamworth property was depopulated and a national survey undertaken to help define the distribution and types of ND viruses circulating in Australia before taking response action on the properties in Western Sydney.
The national survey for ND virus distribution was completed in late 2000. The survey sampling strategy was designed to ensure coverage of all sectors of the Australian commercial poultry industry. Neither isolates of virulent ND virus nor isolates with gene sequences related to the virus outbreaks in New South Wales were detected; all viruses detected were avirulent strains genetically distinct from virulent ND virus. In early 2001, birds on five remaining properties in Western Sydney from which virulent ND virus had been isolated were destroyed. Australia met international standards for freedom from virulent ND virus in October 2001.
There were no further outbreaks of virulent ND in Australia until incidents were confirmed on a single property at Meredith, Victoria, in mid 2002, and on a property at Horsley Park, New South Wales, in late 2002. In both instances, disease eradication processes as prescribed in Australia's AUSVETPLAN disease strategy for the control and eradication of ND were applied.
National response to Newcastle disease
The ratification of the Emergency Animal Disease Response Agreement in March 2002 meant that, for the first time, the private sector was involved in the decision making process during the response to the Victorian outbreak in mid 2002. The Agreement provides for industry representation on the incident National Management Group (NMG), a high level committee responsible for approving emergency animal disease (EAD) response plans and all expenditure relating to the response and recovery from an EAD outbreak. The Agreement also provides for industry representation on the Consultative Committee on Emergency Animal Diseases (CCEAD), the committee of technical experts advising NMG on responses to EAD outbreaks.
An NMG meeting in May 2002 requested that Animal Health Australia coordinate an immediate review of Australia's policy for the management of ND, including topics such as active monitoring and surveillance and compulsory vaccination in designated risk areas. The review was conducted using an expert working group and a national workshop of key stakeholders to develop and agree on the technical and policy issues relating to a national integrated management plan.
The National Newcastle Disease Management Plan 2002/03-2003/04 was developed and the National Newcastle Disease Steering Committee formed. The plan followed a risk management approach, addressing goals for the long-term control of ND, as agreed by industry and government stakeholders. The objectives were to
- Minimise the risk of ND outbreaks from virulent viruses of Australian-origin
- Protect the status of non-infected flocks and regions
- Reduce the social, economic and trade impacts of ND at farm, regional and national levels.
An updated plan for 2005-07 was endorsed by the National Newcastle Disease Steering Committee and Australia's Animal Health Committee. It confirmed the need for a national approach to ND management to reduce the risk that circulating precursor ND viruses mutate into virulent forms, which would result in clinical disease. Vaccination of high-risk areas was a key component of the 2005-07 plan, and a set of vaccination standard operating procedures (SOPs) was prepared.
The National Newcastle Disease Steering Committee has subsequently developed a management plan that will operate for the period 2008-12. The
National Newcastle Disease Management Plan 2008-2012 (277 KB)
is based on, and consistent with, the earlier plans. The goal is to reduce the spread of precursor viruses through the application of poultry industry biosecurity plans and the strategic application and monitoring of vaccination using live V4 and inactivated vaccine. However, the 2008-12 plan includes several new elements designed to reduce the amount of vaccination required by the SOPs, and to ultimately lead to a risk-based exit strategy that may result in a minimal amount of vaccination or no vaccination in chicken flocks at the end of the management period (2012).
Ongoing vaccination represents an undesirable cost to the industry, as does monitoring, and the goal of removing the need for vaccination at the end of 2012 is reasonable. The vaccination program aims to out-compete precursor strains of ND virus that have sequences close to the virulent sequence and that might result in the emergence of virulent ND virus. The new plan includes vaccination (according to revised
Newcastle Disease Vaccination Program Standard Operating Procedures 2008-2012 (209 KB)
) of commercial domestic chickens in all states and territories. In jurisdictions considered to be of low risk for an outbreak of ND, vaccination may be reduced; however, in flocks that opt for reduced vaccination, surveillance protocols as detailed in the plan must be implemented.
Further Information
For further information please contact:
Eva-Maria Bernoth
Manager Emergency Preparedness & Response
Animal Health Australia
Phone: 02 6203 3944
Fax: 02 6232 5511
Email: embernoth@animalhealthaustralia.com.au
Page updated: 26 August 2010