Use of transabdominal ultrasound-guided amniocentesis for detection of equid herpesvirus 1-induced fetal infection in utero.

The research discusses the use of ultrasound-guided amniocentesis to detect in utero infections of Equid Herpesvirus 1 (EHV-1) in horses. It appears successful in early detection of the virus, potentially helping to isolate infected animals and prevent wider outbreaks.

Objective and Methodology

• The objective of the study was to evaluate the potential of using transabdominal ultrasound-guided amniocentesis to detect EHV-1-induced infections in fetuses in horses in utero.
• Four pregnant Welsh Mountain mares were used for the study. These mares were intranasally inoculated with EHV-1 during the ninth month of gestation.
• Amniocentesis, a process through which a small amount of amniotic fluid is sampled using a fine needle inserted into the uterus, was initiated on post-inoculation day (PID) 12. This procedure was performed at 2- to 3-day intervals in standing mares under deep sedation.
• The amniotic fluid samples were then tested using virus isolation (VI), polymerase chain reaction (PCR), and immunoperoxidase cytologic examination (IC) for the detection of EHV-1.

Results

• The mares reacted to the EHV-1 exposure by shedding the virus through their nose, establishing viremia (presence of virus in the bloodstream), and seroconversion (the time point when a specific antibody is detectable in the blood).
• EHV-1 was successfully detected by VI, PCR, and IC in the amniotic fluid collected from the mares, showing that amniocentesis can be used to detect EHV-1-induced infections in fetuses in utero.
• The virus was detected in the first and fourth mare via the chorionic vasculature and in the second mare through inhalation of infected amniotic fluid.
• The third mare was identified as VI negative until PID 18, although it also miscarried an infected fetus on PID 28. This suggests that the detection method may need further refinement for the most accurate results.

Conclusion

• This study concludes that amniocentesis is a useful methodology for the specific detection of EHV-1-induced fetal infections in utero.
• It implies that this technique could play a significant role in identifying and isolating horses carrying virus-infected fetuses in the event of an EHV-1-induced abortion epizootic, an epidemic outbreak in an animal population.