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ARS Home » Southeast Area » Athens, Georgia » U.S. National Poultry Research Center » Exotic & Emerging Avian Viral Diseases Research » Research » Publications at this Location » Publication #313774

Title: Newcastle disease: a high consequence foreign animal disease

Author
item Miller, Patti

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 2/5/2015
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Virulent strains of Newcastle disease virus (vNDV), the etiological agents of Newcastle disease (ND), are not found in poultry in the United States (U.S.). With 68 countries reporting ND outbreaks in domestic poultry to the World Organisation for Animal Health (OIE) from 2013 to 2014, the U.S. must continue to remain watchful for possible outbreaks in wild birds, backyard flocks, and commercial poultry. Transmission of vNDV from wild birds or backyard poultry to commercial poultry facilities has always been a concern. The 2002 Newcastle disease outbreak in southern California, initially spread from backyard gamecocks to the commercial industry and led to millions of dollars in economic losses from the cost of testing, culling, and disposing of infected birds, and from the loss of products to sell and the loss of the ability to export products. The presence of highly pathogenic avian influenza in wild birds in Washington, California, and Utah in 2015 stresses the importance of keeping poultry and wild birds separated. The production of poultry for meat and eggs is an over 20 billion dollar industry for the U.S., which is the top producer of poultry and the second largest producer of chicken meat and eggs in the world. Veterinarians are often the first line of defense in not only keeping backyard poultry healthy, but also identifying disease situations that could impact commercial birds. The clinical presentation of ND can be confused with other diseases. Often the presentation of unvaccinated chicken consists of a bird that is depressed, not eating or moving, with ruffled feathers, possibly with conjunctivitis. Unvaccinated birds may also be found dead with no obvious signs of disease. Well-vaccinated poultry, if challenged with a virulent NDV, will become infected, but may show no signs of diseases except a drop in egg production that starts around one week after the challenge. Thirty days after challenge these birds may lay misshapen eggs that have shells lighter than normal. Chickens that are not well vaccinated often present with various neurological signs that don’t necessarily appear to be related to a respiratory disease. Gross lesions from experimentally vaccinated birds can vary depending on the individual NDV isolate. However, lesions such as enlarged and mottled spleens, and edema, hemorrhage, and necrosis of the cecal tonsil are often found with virulent strains. Gross lesions from outbreaks (specifically the 2002 outbreak in California) are markedly more severe, perhaps due to the partial protection from vaccination, the addition of secondary bacterial infections, and even the possibility of having multiple days of exposure (rather than one day of challenge in experimental conditions). Recognizing the possible clinical signs of ND and advocating good biosecurity practices to prevent transmission to, from, and between flocks is crucial to disease control.