Development of a PCR system for porcine cytomegalovirus detection and determination of the putative partial sequence of its DNA polymerase gene

After PCR amplification with conservative cytomegalovirus primers, a 520 nu cleotide putative partial sequence of the DNA polymerase gene of porcine cy tomegalovirus (PCMV) was determined. Sequence comparison revealed homology to DNA polymerase genes from various beta herpes viruses and a dendrogram w as constructed depicting the relationship of PCMV to other members of the H erpesviridae family. The dendrogram indicates that PCMV is indeed a beta he rpes virus that is more closely related to human herpes virus types 6 and 7 than to type 5. To address the difficulties encountered during conventional PCMV detection and characterization a set of nested PCR primers were constructed which gen erated DNA fragments of 415 and 257 bp from the DNA polymerase gene. The ne sted PCR system proved specific for PCMV and provided a novel means for the detection of this poorly characterized herpes virus in pig populations, va ccines and in organs us ed in xeno transplantation.