Exotic Newcastle Disease
by Michelle Beaupied
Exotic Newcastle Disease (END), also known as Velogenic Vicerotropic Newcastle Disease or the Asiatic or Doyle’s form of Newcastle Disease, affects most species of birds. It is caused by a paramyxovirus called PMV-1. The virus can survive for several weeks in a warm and humid environment and indefinitely in frozen material, making it very dangerous to closely confined flocks of birds. It is one of the most devastating poultry diseases in the world and it is so virulent that many birds die without showing any clinical signs of infection. Mortality rates can near 100% and END can cause death even in vaccinated poultry. Commercial poultry and backyard flocks have the highest risk of infection, but wild birds are also susceptible.
END affects the respiratory, nervous, and digestive systems of birds. Symptoms include gasping for air, sneezing, coughing, nasal discharge, depression, drooping wings, tremors, twisting of the head and neck, circling, complete paralysis, greenish watery diarrhea, swelling of tissue around the eye and neck, partial to complete drop in egg production, the production of thin-shelled eggs, and sudden death. END is spread to a healthy bird by direct contact with an infected bird’s bodily discharges, such as feces or mucous. Feathers, infected carcasses, and aerosol also carry the disease. The disease can be spread indirectly through contact with contaminated trucks, crates, and other farm equipment. Workers can spread the disease from location to location on their shoes and clothing.
END’s cause in the United States is traced to the illegal importation of birds. These birds are not inspected and do not undergo the required United States Department of Agriculture Animal and Plant Health Inspection quarantine. Illegally smuggled Amazon parrots, which can shed the disease for up to 400 days, and infected fighting cocks are known to be END sources.
In October 2002, END was found in Southern California and has spread to parts of Arizona and Nevada. Authorities hope to stop the spread of END by issuing quarantines, inspecting facilities, and destroying birds. Decontaminating clean-ups are required. There is no known cure for the disease. Increasing biosecurity at commercial poultry facilities can prevent future outbreaks and minimize the spread of the disease. Examples of such measures include permitting only essential workers and vehicles on the premises, providing clean clothing and disinfection facilities for all workers, proper cleaning of trucks and hauling equipment, and avoiding visiting other poultry operations.
END can infect wild birds. Double-crested cormorants experienced a large die-off in the early 1990’s from END and more recently, it is believed that a small number of wild pigeons contracted END from feeding and nesting at a contaminated commercial poultry facility.
END does not pose a public health concern and meat and eggs are safe for human consumption.