Europe, Asia, Africa and North America. The name is derived from the town of Borna in Saxony, Germany, which suffered an epidemic of the disease in horses in 1885.
Avian Bornaviruses (ABV), a group of related viruses, have been reported, yet not proven, as the cause of Proventricular Dilatation Disease (PDD), a disease of pet parrots. The use of a 'positive' brain cell culture containing ABV to inoculate another psittacine (parrot) bird resulted in the inoculated bird's death and subsequent histopathological diagnosis of PDD (mononuclear infiltrative ganglioneuritis. Earlier research with purified inoculant of ABV(while did result in the death of parrots) did not reproduce histopathological changes associated with PDD.[citation needed]
Borna disease in sheep and horses arises after a four week incubation period followed by the development of immune-mediated meningitis and encephalomyelitis. Clinical manifestations vary but may include excited or depressed behaviour,ataxia, ocular disorders and abnormal posture and movement. Mortality rates are 80-100% in horses and greater than 50% in sheep.
Borna disease in the horse gives rise to signs like:
• Unusual posture, gait and ear positions
• Movement Disturbances (principally ataxia or excess movement)
History[edit]
The first antibodies to Borna virus in humans were discovered in the mid-1980s. Since then, there have been conflicting results from various studies in regards to whether an association exists between the agent and clinical disease. Antibodies to Borna virus, which indicate prior infection, and Borna virus antigen have also been detected in blood donors.
Psychiatric disease[edit]
There is some evidence that there may be a relationship between Borna virus infection and psychiatric disease.[3][4]
In 1990, Janice E. Clements and colleagues reported in the journal Science that antibodies to a protein encoded by the Borna virus genome are found in the blood of patients with behavioral disorders.[5] In the early 1990s, researchers in Germany, America, and Japan conducted an investigation of 5000 patients with psychiatric disorders and 1000 controls, in which a significantly higher percentage of patients than controls were positive for BDV antibodies.[5] Subsequent studies have also presented evidence for an association between Borna and human psychiatric disorders.[8][9][10] However, not all researchers consider the link between Borna virus and human psychiatric disease to be conclusively proven. A recent study found no Borna virus antibodies in 62 patients with the deficit form of schizophrenia.[11]
Additional evidence for a role of Borna virus in psychiatric disorders comes from reports that the drug amantadine, which is used to treat influenza infections, has had some success in treating depression and clearing Borna infection.[12] Counter-claims state that Borna virus infections are not cleared by amantadine.[citation needed] The issue is further complicated by the fact that amantadine is also used in the treatment of Parkinson's disease and may have direct effects on the nervous system.