[The polymerase chain reaction (PCR) for the detection of DNA of equine herpesviruses 1 and 4].

This research investigates the detection of equine herpesviruses 1 and 4 in aborted equine fetuses using a method known as polymerase chain reaction (PCR). They used formalin-fixed and Paraplast-embedded tissue samples and found evidence of herpesvirus DNA in 9 out of 42 cases.

Research Methodology

• The researchers used tissue samples from 42 aborted equine fetuses to detect the presence of Equine Herpesvirus 1 and 4 (EHV-1 and EHV-4) using the polymerase chain reaction (PCR) technique.
• The tissue samples used were formalin-fixed and embedded in Paraplast, a common preparation method for histological examination.

PCR Technique and Primer Selection

• In this study, the PCR technique was used as a method to amplify and detect minute amounts of DNA from the two types of Equine Herpesviruses. PCR allows for precise identification and quantification of DNA sequences within a sample.
• The primers were designed in a way that they were located in the Glycoprotein 13 open reading frame. An open reading frame is a part of a genome that can potentially code for a protein. Glycoprotein 13 is a specific protein thought to be coded by EHV-1 and EHV-4.
• These selected primers allowed for the amplification of DNA of both EHV-1 and EHV-4, which made subsequent analysis and identification possible.

Cleaving Pattern Analysis

• After amplifying the EHV DNA, they performed a cleaving pattern analysis post Hinf I digestion to differentiate between EHV-1 and EHV-4.
• Hinf I is a restriction enzyme that cuts DNA at a specific sequence. This cutting results in different lengths of DNA strands, known as “cleaving patterns”.
• The resulting cleaving patterns can then be analyzed and compared to known patterns, enabling the researchers to distinguish between EHV-1 and EHV-4 DNA, even though both were amplified by the same set of primers.

Major Findings

• Out of the 42 equine fetal tissue samples investigated, nine were found to hold EHV-1 DNA.
• The research suggests a strong correlation with virological investigations, meaning these findings might contribute to a more accurate diagnosis of equine abortions caused by herpesvirus infections.