Ataxia and paresis with equine herpesvirus type 1 infection in a herd of riding school horses.

This research paper discusses an outbreak of a neurological disease linked to equine herpesvirus type 1 (EHV-1) infection in a group of 46 riding school horses, its symptoms, treatments, and the recovery rates.

Background and Outbreak

• The team worked on a case of an outbreak in a riding school involving 46 horses where EHV-1 related neurologic disease was observed.
• This disease particularly affected 14 geldings (castrated male horses) and 5 barren mares (female horses that cannot produce offspring).

Symptoms

• The infected horses presented with symptoms such as ataxia (lack of muscle control) and paresis (weakness of limbs).
• Further signs included distal limb edema (swelling in the lower legs), head tilt, and urinary incontinence in some horses.
• Additionally, the disease also caused widespread symptoms of fever, depression, and inappetance (loss of appetite) in around 30 horses.

Diagnosis

• 19 out of 44 horses showed an increase in serum neutralizing antibody titers against EHV-1 between acute and convalescent samples, or the numbers exceeded 1:256, confirming recent EHV-1 infection.
• Interestingly, a higher number of mares seroconverted (developed detectable specific antibodies in their blood serum as a response to an infection), indicating a potentially higher susceptibility in female horses.

Treatment and Recovery

• Seven horses with neurologic signs were treated with the antiviral drug acyclovir.
• Out of the 19 affected by the outbreak, 17 horses made a complete recovery, 1 made a partial recovery, while sadly one had to be euthanized due to the severity of the condition.