Equine Parvovirus

Theiler's Disease (Liver Disease)

What is Equine Parvovirus? 

Formerly known as Theiler’s disease (liver disease) is caused by infection with equine parvovirus-hepatitis virus (EqPV-H).

Clinical Signs: The clinical signs are varied as follows:

  • Acute fulminant hepatitis: 
    • Clinical signs are consistent with the horse’s severity of liver disease. 
      • Neurologic signs: head pressing, staggering, behavior changes, blindness 
      • Lethargy 
      • Anorexia
      • Jaundice
      • Discolored urine
      • Colic 
      • Recumbency
      • Death (usually within 72 hours) 
  • Subclinical hepatitis 
    • No clinical signs of liver disease 
    • Mild to moderately elevated liver enzymes
  • Healthy horse (chronic carrier) 
    • No clinical signs of liver disease
    • No abnormalities in liver enzymes 

Diagnosis: Horses clinically affected by hepatitis viruses will have increased liver enzymes and abnormal liver function tests. PCR testing for EqPV-h can be performed on liver biopsies, serum, plasma, or EDTA whole blood at the Animal Diagnostic Center at Cornell.

Treatment: The treatment of equine hepatitis relies primarily on supportive care measures. Referral to intensive care facility is usually needed. 

Prevention: Ensure that serum products administered to horses come from sources free from the virus.