Newcastle Disease - Fact Sheet
What is Newcastle disease?
Newcastle disease is a viral disease that can affect a wide variety of avian species, both wild birds and domestic fowl.
The disease is of great concern throughout much of the world's agricultural community because it is highly contagious and can cause severe disease in poultry.
Strains that produce mild and moderate forms of the disease are sometimes found in domestic poultry and pigeons. The most severe forms of the disease, known as velogenic Newcastle disease (VND), are caused by highly pathogenic strains of the virus. VND can cause severe mortality in chickens.
Is Newcastle disease a risk to human health?
In humans, the Newcastle disease virus can cause conjunctivitis (pink eye). Such cases occur occasionally in laboratory or farm workers that are not wearing protective eyewear. The risk of contracting this form of disease by the public is minimal, particularly if gloves are worn to handle sick birds. Hands should also be washed with soap and water after handling sick birds.
What are the clinical signs of Newcastle disease?
Newcastle disease in birds may affect the respiratory, nervous and gastrointestinal systems.
The clinical signs of Newcastle disease in domestic fowl may include the following:
- decreased egg production;
- high number of sudden deaths in a flock; or
- respiratory distress.
Signs of the disease in wild birds occur mainly in the young and include:
- clenched toes;
- high number of sudden deaths in wild birds, particularly cormorants (wild aquatic, migratory birds);
- inability to walk or fly;
- lack of muscular coordination;
- muscle tremors;
- paralysis of one or both legs or wings;
- twisting of the head and neck; and
- walking in circles.
Where is Newcastle disease found?
Before 1990, Newcastle disease was rarely reported as a cause of death in wild birds. However, since then, small numbers of cases of the disease in cormorants have been found in Canada almost every year, generally in the late summer and fall. None of the outbreaks or cases to date have involved domestic poultry.
How is Newcastle disease transmitted and spread?
Newcastle disease is mainly transmitted by direct contact with diseased or carrier birds.
Infected birds may shed the virus in their feces, contaminating the environment. The virus can survive for days in litter, feed, water, soil, carcasses, eggs and feathers. The disease spreads rapidly among birds in close confinement.
The virus can also spread unintentionally through the movement of contaminated material, footwear and equipment.
How is Newcastle disease diagnosed?
Newcastle disease should be suspected on the basis of clinical signs and also when large numbers of dead wild birds are found.
Newcastle disease can resemble avian cholera, another disease that results in large die-offs of wild birds. Samples must be tested to confirm the presence of Newcastle disease virus, so contact your local veterinarian, provincial wildlife officials or veterinary laboratory for assistance.
How is Newcastle disease treated?
There is no treatment for Newcastle disease. It is not currently possible to vaccinate wild birds.
What is done to protect domestic poultry in Canada from Newcastle disease?
The Canadian Food Inspection Agency (CFIA) works with wildlife officials to monitor Newcastle disease occurrences in migratory and wild birds. The Canadian Cooperative Wildlife Health Centre monitors disease surveillance in wildlife, while CFIA federal laboratories test and diagnose the virus in wild birds. However, given that it is not feasible to eradicate Newcastle disease from wild birds, it is not an objective of Canada's national disease control policies.
Only the velogenic form of Newcastle disease is reportable under the Health of Animals Act. This means that all suspected cases must be reported to the CFIA for immediate investigation by inspectors.
Most of Canada's commercial domestic poultry operators keep their birds in enclosed housing where direct exposure to the disease from wild birds is minimal. Strict biosecurity protocols are followed to protect commercial flocks from disease. For these reasons, the risk to Canada's poultry industry is very small.
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