title: Development and field application of a competitive enzyme-linked immunosorbent assay for detection of Newcastle disease virus antibodies in chickens and ducks.
abstract: A competitive enzyme-linked immunosorbent assay (C-ELISA) using a baculovirus-expressed recombinant nucleocapsid protein antigen (rNDV-N) and an rNDV-N-specific monoclonal antibody (5B3) was developed for the detection of Newcastle disease virus (NDV) antibodies, and its diagnostic performance was evaluated. The specificity and sensitivity of the C-ELISA was found to be 98.4 and 98.9%, respectively, for chickens, and 98.2 and 97.9% for ducks. However, the C-ELISA showed weak cross-reaction with hyperimmune antisera to some other avian paramyxovirus serotypes. In all experimentally vaccinated chickens, seroconversion rates at 7 d postinoculation were 100 and 40% when measured by C-ELISA and hemagglutination inhibition (HI), respectively. In field trials, the C-ELISA showed positive results in 98.9% of HI-positive sera and 40.8% of HI-negative sera from NDV-vaccinated chickens (n = 705). In domestic ducks (n = 158) from NDV-positive duck farms (n = 8), the positive rates according to C-ELISA were significantly higher than those according to the HI test. At the same time, 98.1% of ducks (n = 209) from NDV-negative duck farms (n = 11) were also negative by C-ELISA. Our results indicate that C-ELISA could be a useful alternative to HI testing for detecting NDV antibodies in different avian species such as chickens and ducks.
authors.affiliation: Department of Microbiology and Infectious Disease, Hanoi University of Agriculture, Hanoi, Vietnam.
authors.forename: L V
authors.initials: LV
authors.lastname: Phan
authors.forename: M-J
authors.initials: MJ
authors.lastname: Park
authors.forename: S-J
authors.initials: SJ
authors.lastname: Kye
authors.forename: J-Y
authors.initials: JY
authors.lastname: Kim
authors.forename: H-S
authors.initials: HS
authors.lastname: Lee
authors.forename: K-S
authors.initials: KS
authors.lastname: Choi
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D002645:Chickens; D004372:Ducks; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods / Q000662:veterinary*; D015967:Gene Expression Regulation, Viral / Q000502:physiology; D009521:Newcastle Disease / Q000097:blood* / Q000175:diagnosis; D009522:Newcastle disease virus / Q000276:immunology*; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000378:metabolism; D012680:Sensitivity and Specificity
chemical_list: D000914:Antibodies, Viral; D019590:Nucleocapsid Proteins