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

Abstract

The aim of this study was to use polymerase chain reaction (PCR) to detect and differentiate Equine Herpesvirus Type-1 (EHV-1) and Type-4 (EHV-4) viruses within the racehorse population in Türkiye. The diagnostic sensitivity of PCR was also assessed. For this purpose, 98 nasal swab specimens from naturally infected racehorses aged 2 and above, displaying respiratory symptoms suggestive of EHV infections, and 26 aborted fetuses with various organ samples were collected. DNA extraction and PCR analysis were performed on these samples. The study started with PCR optimization using reference strains of EHV-1 (89c25p) and EHV-4 (TH20p) DNA. Finally optimized was completed and reference strains were used for this study. In conclusion, PCR successfully detected and differentiated 7 EHV-1 positive samples from the tissues of the 26 aborted fetuses, as well as one EHV-1 positive and two EHV-4 positive samples from the nasal swabs of the 98 cases. This study represents one of the pioneering works where PCR was firstly employed to detect and differentiate EHV-1 and EHV-4 strains in Türkiye. The study's findings reveal the presence of both EHV-1 and EHV-4 in Türkiye's racehorse population and is among the early reports to identify the existence of EHV-4 using PCR. These findings underscore the circulation of both viruses within the racehorse population. As a result of this study, it has been concluded that the PCR method is a sensitive, cost-effective, and time-saving diagnostic approach for detecting and distinguishing EHV-1 and EHV-4 infections.