Molecular variability in different Indian isolates of equine herpesvirus-1.

This study examines the molecular variability among different Indian strains of equine herpesvirus-1 (EHV-1), including their potential to cause abortions in horses. The research utilizes DNA fingerprinting techniques to distinguish between the strains and suggests new potential markers for differentiating between them.

Methods and Materials

• The researchers studied three abortigenic Indian isolates of EHV-1 — Tohana, Hisar, and Bikaner — along with two exotic abortigenic isolates (AB4 and V592) and another EHV-1 isolate (Jind) obtained from a case of perinatal foal mortality.
• Their research method involved the use of PCR (Polymerase Chain Reaction) and restriction endonuclease (RE) digestion techniques: both DNA fingerprinting systems used to investigate molecular variability in the viruses.
• Nine different regions of the EHV-1 virus were amplified using primer pairs specifically designed to target these areas. The resulting DNA (PCR products) were further assessed for variability with various restriction endonucleases.

Findings

• The size of the PCR products was consistent across all abortigenic isolates using nine primer pairs, with the exception of primer pairs ‘E’ and ‘C’.
• Using primer pair E, the researchers found that the Tohana and Bikaner isolates were most similar, while the Hisar isolate resembled the V592 isolate. Meanwhile, the Jind isolate fell somewhere between the Hisar and Tohan/Bikaner isolates.
• The primer pair ‘C’ was able to clearly differentiate the EHV-1 isolate obtained from a case of perinatal foal mortality from the other abortigenic isolates. The researchers suggest that more research should be done with this primer to further its use as a potential marker for differentiation.
• Restriction endonuclease studies did not reveal any variations in the position or number of RE sites within the PCR products, indicating no variation in different RE sites within the amplified PCR products. This result shows a level of consistency across the isolates.
• Through this study, it was determined that all the Indian isolates belonged to the IP group of EHV-1.

Implications

• The results of this research may contribute to improved understanding and control of EHV-1 in India, potentially allowing for better differentiation and management of the disease.
• Further exploitation of primer pair ‘C’ could lead to more effective differentiation between abortion-causing isolates versus those associated with perinatal foal mortality, improving prevention and treatment strategies.