Contributed by Guest Blogger: M. Bekhbat ’13
Borna disease virus (BDV) is a neurotropic RNA virus that is known to cause neurological disturbances in various animal species, potentially even humans. It can infect mammals and birds, and can cause fatal encephalitis in horses, cattle and sheep. Experiments with rats indicate that neonatal BDV infection significantly altered the normal pattern of social interaction in rats. A possible relationship between Borna virus infection and psychiatric disease in humans has been speculated for some time now, with disorders most often associated with BDV being bipolar disorder, depression, and schizophrenia. The topic is still debatable with various studies confirming and others rejecting the hypothesis. In this study , the presence of BDV circulating immunocomplexes (CIC), complexes in the circulation formed from antigen (Borna Virus) and BDV-specific antibody, was examined in psychiatric patients and healthy individuals. The study found, like many others did, that the incidence of BDV CIC was significantly higher in psychiatric patients than in healthy individuals. But perhaps the more interesting result was that the significantly higher level of BDV CIC was associated with the higher severity of psychopathology in comparison with patients with mild or moderate psychopathology. This finding is in accordance with results from another research : Patients in the early course of schizophrenia had lower BDV antibody titers compared to patients in the advanced course, while a higher proportion of patients in the early course had titer increases over time. These findings could be the first step to determining putative neurobiological causes and risk factors in common psychiatric disorders, including depression, manic depression, anxiety and schizophrenia, whose causes remain a mystery.
This is a very interesting experiment! It is funny how we treat these diseases with medication while we have no concrete idea of the cause. I wonder, however, about psychiatric diseases such as depression. Environment and upbringing are huge factors in depression, are BDV levels still high in patients who develop depression? If so is it the mental susceptibility of the patient that increases BDV? I can understand BDV levels in patients with bipolar disorder of schizophrenia because people are born with these disorders. Depression is a different story.
Due to the encephalitic nature of BDV in some animals, it is interesting that the virus does not evoke more identifiable virus symptoms in the CIC-positive psychiatric patients. However, given the bit about BDV causing disturbances in rat social interaction, it is plausible that the virus could go undetected in psychiatric patients.
I would be most interested in the level of BDV presence in a larger population of psychiatric patients compared to healthy patients. Perhaps certain facilities with a single BDV-infected patient allow the virus to spread to more patients, especially since it does not appear to be particularly virulent. It would be quite amazing if BDV was able to become widespread among the population of patients suffering from these psychological disorders, while remaining undetected until now.
Most of all, the psychological disorders described as BDV symptoms do not seem to be particularly beneficial to the reproductive success of the virus. One suggestion could be that an individual with a non-fatal neurological disorder is more beneficial for the virus than a dead individual, as they will probably still have contact with other individuals of the population.