What is Newcastle disease?
Newcastle disease is caused by certain strains of avian paramyxovirus serotype 1 virus. The virus occurs worldwide, including Australia, and affects almost all bird species. It is particularly contagious and harmful to poultry, especially chickens. Human infection with Newcastle disease is uncommon, but people exposed to infected birds may experience headaches, flu-like symptoms and conjunctivitis for 1-2 days. There is absolutely no risk to human health from eating poultry or poultry products.
Types of Newcastle disease
There are many strains of Newcastle disease, which vary in their ability to cause illness in chickens. It is important to make the distinction between:
- Australian strains of Newcastle disease
- highly virulent exotic (overseas) strains.
Australian strains of Newcastle disease virus circulate in wild birds without causing harm to those birds. However, if poultry flocks come into contact with these viruses, some of the viruses can mutate, become virulent and cause severe losses. Outbreaks of Newcastle disease occurred in poultry in 1998-2002 in eastern Australia and were costly and difficult to control. In response, the poultry industry and state and commonwealth governments established the National Newcastle Disease Management Plan. The plan is reviewed regularly and the current version covers 2013-2016.
Exotic (overseas) strains of Newcastle disease are generally much more harmful and transmissible than Australian strains. Quarantine measures aim to keep all such viruses out of Australia.
See AUSVETPLAN for technical details of Newcastle disease.
What are the signs of Newcastle disease?
Clinical signs of Newcastle disease are extremely variable depending on the strain and other factors, such as age, general health and immune status of the birds. Signs may range from no obvious clinical signs to a rapidly fatal condition. Typically, clinical signs involve the respiratory, nervous and gastrointestinal systems, and may include:
Highly virulent exotic (overseas) strains
- reduced food intake
- sudden drop in egg production, and abnormal eggs
- coughing, sneezing and difficulty breathing
- dark, thickened combs and wattles
- loss of balance, spasms, circling, convulsions or paralysis of the wings or legs
Australian strains of Newcastle disease
- similar signs as above but less severe and lower death rate.
How does Newcastle disease spread?
Wild birds are the natural reservoir of Newcastle disease viruses. Infected birds spread the virus through their faeces, eye and nasal discharge, and expired air.
Domestic birds can become infected with Newcastle disease by:
- direct contact with an infected bird
- contamination of water or food by infected birds
- contact with people, equipment, vehicles, shoes or clothing contaminated by infected birds.
What is the treatment for Newcastle disease?
There is no treatment for Newcastle disease.
What is my responsibility when it comes to Newcastle disease?
For commercial poultry producers, please refer to Newcastle disease - information for commercial poultry producers.
Newcastle disease is a reportable disease in Western Australia. If you see signs suspicious of Newcastle disease in birds (either Australian strains or highly virulent exotic strains), you are legally required to report it to the Department of Primary Industries and Regional Development, Western Australia (DPIRD). Please call:
- your private veterinarian, or
- your DPIRD field veterinary officer, or
- the Emergency Animal Disease hotline on 1800 675 888.
The earlier the disease is detected, the faster it can be eradicated. If you delay reporting the disease, it will spread to other birds. Because the signs of Newcastle disease are so variable, laboratory diagnosis is required. This can be arranged by your private veterinarian and conducted by DPIRD.
Long-life chickens (layers and breeders) in flocks of more than 1000 birds must be vaccinated against Newcastle disease in accordance with the Code of practice: managing the risk of Newcastle disease in Western Australia. Appropriate vaccination records must be maintained.
Vaccination in meat chickens is not compulsory unless they will be kept for longer than 24 weeks of age. 'Meat chicken’ means any chicken grown for consumption as meat and includes broilers, off-sex layers and free-range meat chickens.
While it is not compulsory, owners of fewer than 1000 chickens are encouraged to vaccinate their birds.
How can I reduce the risk of Newcastle disease occurring in my birds?
As well as meeting reporting and vaccination requirements, high standards of biosecurity are essential to reduce the risk of Newcastle disease as well as other important poultry diseases. Biosecurity standards should include:
- not allowing your birds to have any contact with wild birds
- ensuring your birds’ water supply is not contaminated by wild birds or other animal waste. Water from rain, dams or rivers must be disinfected before use
- ensuring food is not contaminated by wild birds or other animal waste
- controlling rodents
- quarantining new birds
- limiting visitors to your birds. Ensure visitors have clean hands, clothing and footwear, and cover their hair. Dedicated in-shed clothing and boots for farm staff and contractors are strongly recommended
- restricting employees from having contact with any birds outside of work
- keeping equipment and poultry yards clean
- maintaining buildings to exclude wild birds
- cleaning and sterilising returning egg containers or using disposable containers
- locating poultry sheds and aviaries away from wild waterbirds
- washing hands before and after handling birds.
For more information on biosecurity, see the Poultry biosecurity checklist for small landholders and the federal Department of Agriculture bird biosecurity webpage.