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Newcastle disease

Newcastle disease is a highly contagious disease of birds that is caused by a virus. There are many strains of the Newcastle disease virus (NDV) which are classified by the severity of the disease each causes in domestic poultry. In North American wild birds, large mortality events have been reported in double-crested cormorant breeding colonies as early as the 1990s. White pelicans and several species of gulls have also been affected.

In Wisconsin wild bird populations, periodic outbreaks of NDV have resulted in illness and death in breeding colonies of double-crested cormorants, generally occurring in early fall.


Birds infected with NDV shed the virus in exhaled air and other bodily discharges including feces. The virus can also be present in eggs and the carcass of a dead bird. Susceptible birds can become infected by breathing in the virus or by ingesting food or water that is contaminated. Newcastle disease virus is capable of surviving in the environment and on objects such as shoes and clothing. Healthy birds can become infected after contact with contaminated objects.


Signs of disease in birds vary from mild to severe depending on the strain of the virus. In wild populations, signs of infection have only been observed in juvenile double-crested cormorants. These signs have included the twisting of the head or neck, lack of coordination, shaking or paralysis of one or both wings or legs.


Department staff routinely investigate when large numbers of sick or dead wild birds are reported. This is an effective tool for the detection of NDV outbreaks. Control of NDV in wild populations is difficult as large amounts of the virus are shed by infected birds, contaminating the surrounding environment.

The virus is fairly stable and can persist in the environment for long periods under the right conditions. Because the virus is highly contagious and of high risk to domestic poultry, it is important to identify the outbreak site as a contaminated area and follow precautions to prevent the disease from spreading to other areas. When an outbreak in wild birds is detected, care should be taken to limit contact between wild birds and domestic poultry.

If you find a group of dead birds, contact the DNR Wildlife Switchboard by emailing or calling 608-267-0866. You will need to leave a message for the switchboard staff to return your call. In your message, please include the number of animals, the species (such as pelican), if they were sick or dead, the specific location where you saw them, including the county and your contact information.


Newcastle disease infection in humans is rare and usually mild, typically only affecting people in direct contact with infected birds. Signs of infection in humans include conjunctivitis (swelling and reddening of the tissue around the eyes) and mild flu-like symptoms.

When working with or handling birds, there are simple precautions one can take.

  • Wear gloves and safety glasses.
  • Wash your hands after contact with birds or poultry.
  • Avoid touching your eyes until your hands have been washed.