The recent European isolate (08P178) of equine arteritis virus causes inflammation but not arteritis in experimentally infected ponies.

This research investigates a recent European strain of equine arteritis virus (EAV), specifically 08P178 from Europe, and its effects on ponies. While the virus causes inflammation, it was found not to cause arteritis in infected ponies.

Objective and Methodology

• The research aimed to study the microscopic changes and lessons caused by the European strain (08P178, EU-1 clade) of EAV on ponies in an experimental setting.
• The selected ponies were subjected to the virus and later euthanised at various stages post-infection for examination, specifically at 3, 7, 14 and 28 days.

Findings and Observations

• On the third day post infection (dpi), microscopic lesions were largely confined to the ponies’ respiratory tract and intestines. At this stage, the main observed abnormalities were slight, widespread epithelial degeneration and associated mononuclear cell infiltration.
• The seven-days mark post-infection saw an escalation in severity of these lesions.
• By the 14th day, the lesions in the respiratory region grew more serious, and the lymphoplasmacytic infiltration – the movement of lymphocytes and plasma cells into an affected area – extended to other organs.
• Even until the 28th day, lesions persisted, particularly in the viscera (internal organs).
• Across all specimens, the most noticeable histological alteration was a variable degree of lymphoplasmacytic infiltration in intraepithelial, subepithelial and perivascular locations.
• Contrary to traditional associations with the term arteritis, no symptoms of arterial damage like infarcts, haemorrhages or necrosis were observed.

Conclusion

• The study concluded that the European 08P178 strain of EAV, when administered to susceptible animals, resulted in inflammation without causing arteritis.

This research advances our understanding of the varied impacts of EAV strains on equine health and serves as a useful reference for veterinary pathologists and virologists.