Sequence variation at a Bmy I/Rsa I restriction site in ovine herpes virus 2

Abstract DNA samples extracted from a bovine brain, one blood and one buffy coat sample from three cattle with malignant catarrhal fever, and from 47 samples of pooled sheep sera, were amplified by nested polymerase chain reaction (PCR) using primers specific for ovine herpes virus 2 (OHV-2). Confirmation of the specificity of the amplified DNA segment by restriction enzyme analysis with Rsa I and Bmy I as described by Baxter et al. [1] was obtained in most samples. Nine amplified DNA samples could not be digested, or were only partially cut, with these enzymes. Sequencing of six samples revealed a two-nucleotide substitution in the middle of the restriction site (AA vs. CG) in four of these samples (the bovine brain and three sera), and two peaks at each of these positions (C or A, G or A) in two samples from pooled ovine serum. These results indicate the existence of a variant of OHV-2, and that both the previously sequenced OHV-2 and the variant were present in some samples of pooled ovine serum.