A study of the pathogenesis of equid herpesvirus-1 (EHV-1) abortion by DNA in-situ hybridization.

The research investigated how equid herpesvirus-1 (EHV-1) results in abortions in infected horses using advanced molecular techniques. The study found that viral genetic materials spread across the placenta and into endometrial glands in the uterus, implicating a role of vascular endothelial cells, tissues forming the inner lining of blood vessels, in the disease’s progression.

Research Methods

• The research utilized polymerase chain reaction (PCR) and DNA in-situ hybridization to investigate sections of uterine tissue collected from infected mares around the time of abortion. PCR is a lab technique used to amplify and thus detect trace amounts of DNA, while DNA in-situ hybridization is a molecular method used to pinpoint where specific DNA sequences reside in tissue.

Key Findings

• The researchers found viral nucleic acids (genetic building blocks of the virus) in endothelial cells — cells that line the inside of blood vessels — of endometrial arterioles, which are small branches of arteries leading to the endometrium (the lining of the uterus).
• Interestingly, viral nucleic acids were also found in cellular debris within endometrial glands and moving across the placenta at places where there was microcotyledonary infarction (blockage of blood supply to the tiny, leaf-like structures, or cotyledons, that are part of the placental tissue).
• Despite inflammation around the blood vessels (perivascular cuffing), the white blood cells (leucocytes) surrounding the vessels were generally virus-free.

Research Significance and Conclusion

• The findings from this research provide additional support to the theory that vascular endothelial cells play a key role in the mechanism by which EHV-1 infection leads to abortion in horses.
• The research also demonstrates that the viral nucleic acids directly spread across the placenta and into endometrial glands around vascular damage sites, suggesting potential routes of viral spread and areas of infection within the reproductive system of the horse.