First report of equine parvovirus-hepatitis-associated Theiler's disease in Europe.
Authors: Vengust Modest, Jager Mason C, Zalig Valentina, Cociancich Vasilij, Laverack Melissa, Renshaw Randall W, Dubovi Edward, Tomlinson Joy E, Van de Walle Gerlinde R, Divers Thomas J
Journal: Equine veterinary journal
Summary
# Editorial Summary: Equine Parvovirus-Hepatitis and Theiler's Disease in Europe Theiler's disease, a severe and often fatal hepatitis in horses, has long been suspected to involve equine parvovirus-hepatitis (EqPV-H) as its causative agent, though this link had never been confirmed in European cases until now. Vengust and colleagues examined four horses from a single studfarm that died from Theiler's disease during a 2018–2019 outbreak, reviewing clinical records, biochemical findings, and necropsy data; three of the four had received tetanus antitoxin within 7–11 weeks prior to illness, a notable temporal association. PCR and in situ hybridisation assays confirmed EqPV-H in liver tissue from all four horses, with viral nucleic acid ranging from widespread hepatocyte distribution to more scattered localisation depending on the case. This first European documentation of EqPV-H-associated Theiler's disease, coupled with the novel visualisation of viral nucleic acid patterns using in situ hybridisation, strengthens the aetiological case for parvovirus involvement and raises important questions for practitioners about the potential role of biological products and their temporal relationship to fatal hepatitis—warranting heightened clinical suspicion and systematic testing in similar presentations across European populations.
Read the full abstract on PubMed
Practical Takeaways
- •Veterinarians should be aware that tetanus antitoxin administration may be associated with EqPV-H-related Theiler's disease and should monitor vaccinated horses closely for signs of hepatic disease
- •Theiler's disease in Europe should now be tested for EqPV-H using PCR; consider liver biopsy or necropsy samples from suspected cases for diagnosis
- •Farm outbreaks of acute hepatitis in horses warrant investigation for EqPV-H, particularly in animals with recent serum product administration
Key Findings
- •EqPV-H was detected in liver tissue from all four horses with fatal Theiler's disease using PCR testing
- •Three of four horses had recent tetanus antitoxin administration (7-11 weeks prior) suggesting a potential triggering factor
- •In situ hybridisation revealed both widespread and sporadic distributions of viral nucleic acid in hepatocytes across the four cases
- •This is the first documented case of EqPV-H-associated Theiler's disease reported in Europe and the first use of ISH visualization in equine Theiler's disease