EN
The purpose of the study was a preliminary evaluation of the usefulness of Wrocław-2 EAV strain modified in cell culture lines as a live-virus vaccine used in prophylaxis against EVA. In four one year old horses vaccinated intravenously with Wrocław-2 strain was observed apathy lasting for several days, a moderate ocular conjunctiva congestion, and in 1 out of 4 horses postvaccination fever occurred on the day 5th. The virus was reisolated only from conjunctival swabs in 2 horses on the 2nd day after immunization. The peak titre of virus neutralizing antibodies — from 1/512 to 1/1024 — was noted after 2—3 weeks since the vaccination. After exposure of vaccinated horses to a virulent Bocyrus EAV strain clinical signs of disease were not observed, virus was not recovered from any of swabs and the secondary humoral immune response was characterized by a very sharp and rapid increase of titres of neutralizing antibodies. However in the unvaccinated control horse, acute arteritis occurred and viral shedding was intensive and longlasting. The virus was reisolated from conjunctival, nasal, oral, rectal and preputial swabs.