Newcastle disease occurs in two basic forms, the common form, or Newcastle Disease, and Exotic Newcastle Disease. Exotic Newcastle Disease is rare and is a federally reportable disease. If fifty percent or more of your flock dies suddenly, contact your state veterinarian, who will provide information on how and where to get a definitive diagnosis of the disease affecting your flock.
Newcastle Disease is more common, causes fewer, less severe symptoms and is less economically important. This fact sheet will focus on Newcastle Disease. For more information on Exotic Newcastle Disease visit http://www.aphis.usda.gov/animal_health/birdbiosecurity/END/ for a complete description of the disease and the measures in place to prevent widespread disease.
Transmission
Newcastle Disease virus is present in high concentrations in the bodily secretions of infected birds. The virus is spread by air, contact with body secretions, and by contaminated water and feed.
Signs
Young, growing birds exhibit respiratory signs such as wheezing, gasping, coughing and chirping. Nervous symptoms may follow in 10 to 14 days, resulting in leg, wing and/or neck paralysis. If nervous symptoms are present, high death losses may result from an inability to reach food and water and from trampling by pen mates.
Adult birds show only slight respiratory signs including nasal discharge, and cloudy eye. Additionally, there may be a slight decrease of egg production. Eggs may be misshapen and have rough shells.
Morbidity and Mortality
A large number of the flock may be affected, but death losses will be low unless nervous symptoms develop. Adult birds may show few if any signs and recover without intervention. Recovered birds can remain carriers for up to one month.
Diagnosis
Diagnosis is made from the symptoms, respiratory and nervous, in young birds, and by positive identification of the virus through laboratory tests.
Prevention
If Newcastle Disease is prevalent in your area, vaccinate at 1 day of age, (vaccine may be delayed to 7-10 days of age) and re-vaccinate every 4 months. Vaccinate adult birds when you first vaccinate the young. Other prevention measures include adherence to bio-security and breeding for resistance.
Treatment
Once signs appear, provide supportive therapy, and keep the flock warm and well-fed. Protect birds exhibiting nervous symptoms from being trampled. Watch for secondary, opportunistic bacterial infection.
