Objective—To determine whether a herpesvirus isolated
from the semen of a North American elk was
related to bovine herpesvirus 1 (BHV-1).
Sample Population—Semen from 1 healthy bull elk
and 2 subtypes of BHV-1 (BHV-1.1 and BHV-1.2).
Procedures—A virus with cytopathic and electron
microscopic characteristics consistent with an alphaherpesvirus
was isolated from elk semen, using fetal
bovine kidney cells. Cross-neutralization assays were
performed with antisera against BHV-1 and the elk
herpesvirus (ElkHV). Restriction endonuclease
digests of ElkHV DNA were compared with digests of
BHV-1.1 and BHV-1.2 DNA. A portion of the ElkHV
DNA polymerase gene was amplified with consensus
primers by use of the polymerase chain reaction and
sequenced. Sequence was compared with known
sequences of other herpesviruses. An immunoperoxidase
monolayer assay was used to determine reactivities
of 22 BHV–1-specific monoclonal antibodies
(mAb) against ElkHV. In vitro neutralizing activities of
the reactive mAb were determined by use of a
Results—Results of cross-neutralization assays indicated
that ElkHV was serologically related to BHV-1.
Endonuclease digestion of ElkHV DNA generated
fragments that were distinct from those of BHV-1.
Nucleotide sequencing confirmed that ElkHV is an
alphaherpesvirus closely related to but distinct from
BHV-1. Six of 22 BHV–1-specific mAb reacted against
ElkHV; 2 of these 6 also neutralized in vitro infectivity
Conclusions and Clinical Relevance—ElkHV is antigenically
and genetically distinguishable from BHV-1.
However, the viruses are serologically related and
share at least 6 antigenic determinants, one of which
is a major neutralizing determinant. (Am J Vet Res