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Repeated Challenge with Virulent Newcastle Disease Virus Does Not Decrease the Efficacy of Vaccines.
- Source :
-
Avian diseases [Avian Dis] 2017 Jun; Vol. 61 (2), pp. 245-249. - Publication Year :
- 2017
-
Abstract
- Globally, poultry producers report that birds well-vaccinated for Newcastle disease (ND) often present clinical disease and mortality after infection with virulent strains of Newcastle disease (vNDV), which is contrary to what is observed in experimental settings. One hypothesis for this discrepancy is that the birds in the field may be exposed to multiple successive challenges with vNDV, rather than one challenge dose, and that the repeated infection may overwhelm the immune system and neutralizing antibodies available to prevent clinical disease. In this study, we evaluated this hypothesis under highly controlled conditions. We challenged well-vaccinated chickens with high doses of vNDV daily for 10 days, and looked for signs of clinical disease, changes in antibody titers, and mortality. All sham-vaccinated birds died by the fourth day postchallenge. No morbidity or mortality was observed in any of the NDV-vaccinated birds up to 14 days postchallenge; repeated high-dose challenges of vNDV was not sufficient to overcome vaccine immunity.
- Subjects :
- Animals
Antibodies, Neutralizing immunology
Antibodies, Viral immunology
Chick Embryo
Chickens
Newcastle Disease immunology
Newcastle Disease prevention & control
Newcastle disease virus genetics
Newcastle disease virus pathogenicity
Viral Vaccines administration & dosage
Viral Vaccines genetics
Virulence
Newcastle Disease virology
Newcastle disease virus immunology
Viral Vaccines immunology
Subjects
Details
- Language :
- English
- ISSN :
- 1938-4351
- Volume :
- 61
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Avian diseases
- Publication Type :
- Academic Journal
- Accession number :
- 28665733
- Full Text :
- https://doi.org/10.1637/11555-120816-ResNote.1