Equine herpes myeloencephalopathy.

This research paper examines the neurologic form of Equine herpesvirus-1 (EHV-1) infection in horses, otherwise known as equine herpes myeloencephalopathy. The researchers found that this equine disease, characterized by infarction in the central nervous system, could be caused by a previous EHV-1 infection, with its pathogenesis and treatment methods still largely unknown. Researchers also observed that while there’s no vaccine yet for the neurologic form, regular vaccination can reduce other EHV-1 related illnesses and indirectly prevent this form of the disease.

Pathogenesis of EHV-1

• The paper discusses the neurologic form of EHV-1 infection, characterized by an infarction in the central nervous system due to vasculitis. Vasculitis is inflammation of the blood vessels, in this instance, initiated in the endothelial cells of small blood vessels.
• The cause of this neurologic disease is the Equine herpesvirus-1, subtype 1. This virus may not cause the disease immediately; there is evidence that the neurologic form of the disease might result from a reactivation of a previous infection.
• However, it is unclear whether the vasculitis and subsequent central nervous system injury are directly due to the infection or are a form of immune response to the infection.

Clinical Signs and Diagnosis

• The symptoms of this neurologic disease are sudden, not evolving over time, and many horses may show signs of improvement.
• Diagnosis of this form of EHV-1 can be challenging, particularly in horses that recover, due to the lack of a definitive confirmatory test. Thus, most diagnoses tend to remain tentative.

Treatment and Prognosis

• The prognosis for horses affected by this form of EHV-1 is generally good, although they might recover slowly and not fully.
• Supportive therapy is crucial and corticosteroids could potentially be helpful.
• However, there is, as of now, no specific treatment available for the virus or the vasculitis.

Prevention and Vaccination

• Though no vaccine directly protects against the neurologic form, vaccination is advised to decrease the occurrence of respiratory disease, abortion, and neonatal deaths linked to EHV-1 infection.
• To maintain presumably protective antibody concentrations, repeated vaccinations are necessary, possibly every 3 to 4 months.
• Such a schedule may decrease the incidences of EHV-1 infection on the farm, and therefore indirectly prevent the occurrence of the neurologic form of the disease.