Immunological as well as nucleic acid hybridization
detection assays often suffer from
poor specificity especially when using tissue extracts
or biological fluids as samples. This is
mainly due to either cross-reactions with nontarget
proteins (enzyme immunoassays or EIA) or
nucleic acids (hybridizations) or simply non-specific
molecular interactions. The WB protocol has
a distinct advantage over these other detection
protocols, in that in addition to the specific antigen–
antibody interaction it also separates the vi-ral proteins on the basis of their size. Therefore, a
stricter criterion is applied in the identification of
positive samples. Both the EIA and WB detection
protocols are currently being evaluated by this
laboratory in field studies of samples obtained
from various hatcheries and farms and the initial
results strongly indicate that the WB protocol is a
highly reliable confirmatory assay for the less
specific but more convenient EIA