Equine herpesvirus 1 infection of horses: studies on the experimentally induced neurologic disease.

The study involves an experiment on horses infected with the equine herpesvirus 1 (rhinopneumonitis), revealing various medical conditions and the reaction of the horses at different gestation stages. Particularly, neurological syndrome was common among mares between 3 and 9 months of gestation.

Research Objective and Methodology

• The researchers set out to explore the effects of equine herpesvirus 1 (rhinopneumonitis), a virus that affects horse’s respiratory system, on horses.
• They conducted an experimental infection on 15 horses and closely monitored their conditions.
• The horses were segregated into groups of different gestation stages, and each group was studied for developing clinical symptoms post inoculation.

Findings and Observations

• Eight out of fifteen inoculated horses developed neurologic disease as a result of the infection.
• The non-pregnant horses did not show any symptomatic reactions to the infection, as revealed by microscopic examination of their tissues.
• All the mares were affected differently – those between 3 to 9 months of gestation developed neurological syndromes within 6 and 8 days of inoculation. However, mares at 10 months did not show any neurologic disorders, though some ended up aborting instead.
• The researchers also discovered that vasculitis, a condition involving the inflammation of blood vessels, was common in both types of reactions. This was apparent in smaller arteries and veins.
• While blood vessel changes were detected in the endometrium of all pregnant horses, such changes were only recorded in the central nervous system of mares with neurologic disease. This suggested a cause-effect relationship between blood vessel changes and neurologic disorders in horses after infection with the equine herpesvirus 1.
• In addition, degeneration of nervous tissue within the central nervous system was observed, further implying the existence of neurologic disease in the infected horses.
• An increase in protein but not pleocytosis (an increase in the number of white blood cells in cerebrospinal fluid) was observed in cerebrospinal fluid from affected mares.

Conclusions

• The research affirmed that the equine herpesvirus 1 infection can cause neurologic disease in pregnant horses, with the severity of the diseases largely dependent on the gestation stage of the mare.
• This experiment emphasizes the need for further studies to affirm these findings and develop effective treatment and prevention strategies.