Molecular and Immunological Detection of Bovine Herpesvirus-1 in Clinical Specimens
Alaa A. El-Kholy
Veterinary Serum & Vaccine Research Institute,
Abbasia, Cairo, Egypt.
A nested polymerase chain reaction (nested-PCR), utilizing
glycoprotein B (gB) gene of bovine herpesvirus-1 (BHV-1) as a target, virus
isolation (VI), indirect immunofluorescence (IFA) and In situ
immuno-peroxidase (IPr) staining in cell culture were conducted for detection
of BHV-1 in
suspected cattle, buffalo and sheep clinical specimens. The specimens were
obtained in the form of nasal swabs, buffy coats and sera from different
localities in Egypt
(El-Sharquia, Dumyat and El-Fayoum). A total
of 15/93 (16.1%) of cattle, 4/55 (7.3%) of buffalo and 0/31 (0%) of sheep
clinical specimens were BHV-1 positive in this study. Nested-PCR was superior
to immunodetection using IFA and IPr after VI procedure. Besides, it was the
most discriminative assay that detected BHV-1 viral DNA extracted directly from
cattle and buffalo clinical specimens (100%). While, none of the sheep viral
isolates (0/3; 0%) could be identified as BHV-1 by nested-PCR, although 2/3 of
these isolates (from nasal swabs) tested positive by IFA, IPr and the first
round PCR. Also, a buffy coat buffalo viral isolate tested positive with the
first round PCR while, it turned repeatedly negative to VI, IFA, IPr and
nested-PCR testing. These nested-PCR negative viral isolates were regarded as
antigenically related, yet genetically distinct, other ruminant herpes viruses
that require further studies. Findings of this study emphasized the
preponderant utility of the BHV-1 gB based nested PCR as a sensitive,
discriminative and rapid tool for epidemiological studies and control programs
of BHV-1 infections, without confusion with other ruminant herpesviruses.
Accordingly, it is recommended for routine screening of not only local but also
imported animals and biologics for BHV-1 contamination.