Rapid, single-step differentiation of equid herpesviruses 1 and 4 from clinical material using the polymerase chain reaction and virus-specific primers.

The research article focuses on a rapid method for differentiating between equine herpesviruses 1 and 4 using polymerase chain reaction and virus-specific primers. The specificity of this method was confirmed, and it proved to be highly correlated with traditional virus isolation methods for these viruses.

Research objective and methodology

• The research was aimed at designing a rapid, specific, and effective method of distinguishing between two types of equine herpesviruses, EHV-1 and EHV-4. The researchers achieved this differentiation by developing specific primers to amplify homologous regions of the glycoprotein C and gene 76 genetic loci of the viruses.
• The developed method uses the polymerase chain reaction (PCR), a widely-used molecular biology technique for amplifying a specific DNA sequence. The PCR products generated from each virus loci could be quickly and easily distinguished based on their size when run on an agarose gel, making it possible to identify the two herpesviruses.

Validation of the methodology and application

• To confirm the specificity of the PCR amplifications, the researchers utilized Southern hybridization, a method that detects specific DNA sequences within DNA samples, and digestion by restriction endonucleases, enzymes that cut DNA at specific recognition sequences. These techniques affirmed the specificity of the PCR results.
• The new PCR method was then applied to nasal swab samples from weanling foals and to archival aborted fetal tissue samples. The PCR results were compared to the results of traditional virus isolation methods.

Research findings

• The researchers found a strong correlation between the PCR assay results and the results from virus isolation, suggesting that the PCR method is reliable and effective for detecting and distinguishing between EHV-1 and EHV-4.
• The new method offers a faster alternative to traditional virus isolation methods, providing rapid differentiation of the two equine herpesviruses.