Detecting Equine Herpesvirus-1 and Equine Herpesvirus -4 Infections in Racehorses using Polymerase Chain Reaction

Abstract

The aim of this study was to detect and differentiate equine herpes virus type-1 (EHV-1) and type-4 (EHV-4) by polymerase chain reaction (PCR). The diagnostic sensitivity of the PCR was also examined. For this purpose, suspicious samples obtained from different breeding farms and racehorse hospitals were used. During this study, multiple organ and tissue samples of 26 aborted fetuses were collected and analyzed with PCR. In addition, 98 nasal swab specimens from racehorses aged 2 and above representing the respiratory symptoms of EHV infections were collected and examined by the PCR method. This study started with the optimization of PCR using EHV-1 (89c25p) and EHV-4 (TH20p) DNA, which are reference strains. It was observed that the gB common oligonucleotide primers and species-specific gC primers used in optimization matched the viral DNA specific for target EHV-1 and EHV-4.Finally 7 EHV-1 positives at tissues of aborted fetuses of 26 and 1 EHV-1 and 2 EHV-4 positives at nasal swab samples of 98 has been detected and differentiated by PCR. This was the first PCR study to detect and differentiate EHV-1 and EHV-4 in Turkey. Results of this study reveal the presence of EHV-1 and EHV-4 in Turkey. Especially the presence of EHV-4 virus has been shown for the first time. As a result of the study, detection of EHV-1 and EHV-4 genomic DNAs by PCR indicated that both viruses circulate between racehorse population.In conclusion, we agreed that the PCR is a sensitive, economical and time-saving method in detecting and differentiating EHV-1 and EHV-4 infections.
 Key words:EHV-1, EHV-4, infection, Polymerase Chain Reaction (PCR)