08/11/2025
🩸 Recently, a 17 year old draft gelding in Virginia tested positive for Equine Parvovirus. And we thought that we would break this disease down for horse owners with Dr. Lauren Holley, ACVIM.
🩸 Did you know horses can get Parvovirus too?
Unlike dogs (who get GI signs), Equine Parvovirus causes liver disease (hepatitis).
💡 EqPV-H has been linked to Theiler’s Disease (Serum Hepatitis) — once thought to occur only after blood transfusions, but we now know horses can get it without any blood product exposure.
👉 We test all of our blood donors for Equine Parvovirus, and our plasma comes from rigorously screened, verified sources.
🩸 Most horses with EqPV-H don’t get sick — only 1–2% show signs of hepatitis. Mild cases often resolve on their own in a few weeks (1-12 weeks), with the only indication being elevated liver enzymes on blood work.
🪧 Typical signs of liver disease or hepatitis include:
💤 Lethargy
❌ Inappetence
💛 Yellow discoloration of the mucous
membranes (eyes, gums, v***a)
🌞 Photosensitization - abnormal
sunlight sensitivity causing blistering
and sunburn on the ‘non-pigmented’
or ‘white’ areas of the coat.
🤢 Colic
🛏️ Recumbency
🧠 In severe disease - Neurologic signs (hepatic encephalopathy) including altered behavior, head pressing, staggering and blindness.
🩺 Diagnosis
Clinical signs, elevated liver enzymes on blood work (AST, SDH, GLDH and GGT) and changes in markers of liver function (ammonia and bile acid concentrations).
PCR testing for the virus (in both blood and liver samples). A positive blood test doesn’t always mean active disease — horses can test positive up to a year after infection.
💊 Treatment and Prognosis
Only symptomatic horses require treatment → aggressive supportive care and secondary treatment of liver dysfunction - especially in the case of neurologic signs.
The prognosis with mild to moderate clinical signs is excellent. Severe disease, fulminant liver failure and neurologic signs, the mortality rate can be high.
💉 Prevention
No vaccine available
When administering biologic products (stem cells, plasma, etc), it is best to use autogenous biologics (from the patient's OWN blood) or commercial products that are known to be negative.
☣️Biosecurity
Not enough is known about EqPV-H. Traditional approaches to limiting the spread of diseases in outbreaks and good quarantine practices when introducing horses to barns are recommended.
📸: A foal receiving a blood transfusion.