Equine parvovirus hepatitis.
Authors: Ramsauer Anna Sophie, Badenhorst Marcha, Cavalleri Jessika-M V
Journal: Equine veterinary journal
Summary
Equine parvovirus hepatitis (EqPV-H) emerged in 2018 as a significant pathogen associated with Theiler's disease, a devastating acute hepatitis characterised by fulminant hepatic necrosis with high mortality rates, though the virus has since been identified across asymptomatic populations worldwide. The research synthesises evidence demonstrating that EqPV-H is hepatotropic and causally linked to clinical disease ranging from subclinical hepatitis to severe, fatal presentations, with transmission occurring both iatrogenically through contaminated equine-origin biological products (particularly equine serum and antitoxins) and horizontally amongst in-contact horses via poorly defined routes including potential arthropod vectors. Affected horses typically present with icterus, lethargy, inappetence and neurological signs alongside elevated liver enzymes, whilst histopathological examination reveals hepatocellular necrosis, lobular architectural collapse and lymphocytic infiltration; experimental infection in most horses produced subclinical hepatitis with clear temporal associations between peak viraemia, seroconversion and hepatic injury. For practitioners, this review underscores the necessity of considering EqPV-H as a differential diagnosis in any case of acute hepatitis and highlights the critical importance of rigorous scrutiny regarding the sourcing and safety protocols of equine-origin biological products, given the virus's documented capacity for severe systemic infection and the substantial welfare and economic consequences of Theiler's disease.
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Practical Takeaways
- •Consider EqPV-H as an important differential diagnosis when evaluating horses presenting with acute hepatitis or Theiler's disease signs
- •Be aware that equine-origin biological products (serum, antitoxins, stem cells) carry transmission risk; verify product safety protocols and sourcing
- •Monitor in-contact horses following cases of EqPV-H hepatitis, as horizontal transmission through oral route and other means has been documented
Key Findings
- •EqPV-H was first described in 2018 and is now frequently identified in horses with Theiler's disease, a fatal acute hepatitis
- •Transmission occurs horizontally via contaminated equine-origin biological products (serum, antitoxins, mesenchymal stem cells) and potentially oral routes
- •Clinical signs in affected horses include icterus, lethargy, inappetence, neurological abnormalities, and elevated liver-associated biochemistry parameters
- •Worldwide prevalence of EqPV-H antibodies and DNA exists in asymptomatic horses, while experimentally infected horses predominantly develop subclinical hepatitis