Summary
An
antigen capture ELISA for bluetongue (BT) virus was developed using
tissue culture supernatant to identify different BT virus (BTV)
serotypes 1, 2, 4, 9 and 16, which have been incriminated in the
current epidemic in the Mediterranean Basin. To obtain a positive
result and after amplification in tissue culture, the minimum amount
of infecting virus required was 100 TCID50. Results from the antigen
capture ELISA were compared with conventional methods for virus
isolation and identification, such as virus amplification on embryonated
chicken eggs (ECEs), followed by tissue culture and the direct immunofluorescence
test. The sensitivity and specificity of the ELISA in infected tissue
culture supernatant using homogenates of BTV-positive ovine and
bovine organs and blood, without a previous step in ECEs, were 100%.
The assay was also applied to homogenates of chicken embryo tissues,
which had been infected with different BTV serotypes. This method
enabled detection of the virus with 100% sensitivity and specificity
rates, also using amplification in ECEs. Furthermore, among the
various embryo tissues tested, liver was found to be the most suitable
for use with ELISA. In experimentally infected ovine blood samples,
the ELISA revealed the presence of the virus. Given the high sensitivity
and specificity obtained with the BTV serotypes in this trial, the
method should greatly facilitate BT diagnosis.
Keywords
Antigen
capture, Bluetongue, Bluetongue virus, Chicken embryos, Diagnostic
tests, Enzyme-linked immunosorbent assay, Tissue cultures, Viruses.
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