Borna disease is a neurological infection caused by Borna disease virus (BDV). The typical symptoms of the disease include behavioral disturbances and movement disorders. Classical Borna disease is a progressive fatal meningoencephalomyelitis. The disease was reported for the first time in horses in Germany more than 200 years ago. During the last decades, BDV has been found to infect and cause clinical disease in many other species as well. Human infections have also been reported, but the evidence is controversial. More recently, Borna disease has been described in cats and horses in Sweden. The disease should be kept in mind also in Finland, when patients with typical symptoms are examined.A research project has been started to find out whether BDV exists in Finland.
According to present knowledge, alphaherpesvirus infections are the most prevalent clinically significant viral infections of equine species. Latent infection, a characteristic feature of herpesviruses makes it difficult to resist them. Although the clinical signs resulting from infection are mainly mild, virulent equine herpesvirus 1 (EHV-1) strains can induce abortions, neurological signs and fatal disease of foals.
A case report of typical equine herpesvirus-1, outbreak in a stable of 18 horses is described. Sixteen of the horses were febrile for 3�7 days. One horse developed neurological signs on the fifth day of fever and was euthanised on the fourth day after first neurological signs. The euthanised horse and three other mares were pregnant. Two of them aborted. The diagnosis of EHV-1 was confirmed with serology and viral isolation.