DNA-Muster von gegenwärtig zirkulierenden Isolaten des Equinen Herpesvirus Typ 1

Recently, reports on outbreaks of infections with equine herpesvirus type 1 (EHV1) causing neurological disorders have become more frequent. The apparent change in the clinical picture has increased uncertainty of horse owners and veterinarians worldwide. It is unknown whether the actual problems are caused by strain variation resulting in increased virulence, by changes in animal husbandry, or simply by an increased awareness and international communication of problems. In addition, the efficacy of the vaccines used to control EHV1 infections is questioned, mainly from a formulation standpoint and from the fact that vaccines contain strains that are relatively outdated. To initially assess putative genetic changes within circulating EHV1 strains, DNA patterns of isolates obtained from either aborted fetuses or horses which had been euthanized as consequence of severe neurological disease were compared. Viral DNA was digested with restriction enzymes BamHI, EcoRI and HindIII and analyzed by agarose gel electrophoresis. The analyses demonstrated that no major changes in the fragment patterns became obvious, indicating that currently circulating viruses are very similar to known reference strains that were isolated over the past 50 years.