2/3. Genetic relationship of borna disease virus isolates. The infection of humans with Boma disease virus (BDV) is still a matter of debate. In a recent publication, we described a BDV (RW98) isolated from the blood of a psychiatric patient. The RNA of this virus differed more than 5% from that of the widely used strain He/80, which was supposed to represent our laboratory virus. Here, we show that the virus used in our laboratory was not He/80 and, furthermore, that RW98 has sequence identity to the laboratory strain. We also present data that BDV-specific nucleic acid detected in blood of the donor of the presumed RW98 isolate and one other patient differs from all known BDV-p24 sequences, arguing for the existence of BDV sequences in man. ( info) |
3/3. Clinical similarities and close genetic relationship of human and animal borna disease virus. borna disease virus (BDV) is the prototype genus of a new family, bornaviridae, within the order mononegavirales. BDV naturally infects animals and man. The symptomatology in animals ranges from subclinical infection to rare cases of encephalitis. Asymptomatic infection seemed more frequent than expected, based on antibody data from 100 healthy horses derived from different stables with a history of diseased cases (30-40% carriers). Likewise, phasic episodes of a neurobehavioral syndrome followed by recovery were much more common than fatal neurologic disease. They were paralleled by expression of BDV antigens (N-protein p40, P-protein p24) and RNA transcripts in peripheral blood mononuclear cells, indicating viral activation. Representative longitudinal studies showed that episodes of depressive illness in humans as well as apathetic phases in infected horses were accompanied by antigen expression and followed a similar clinical course. After recovery, BDV antigen disappeared. This temporal congruence, together with the recent isolation of infectious BDV from such patients, points to a contributory role of this virus in human affective disorders. Successful amelioration of BDV-induced neurobehavioral disease in horses with antidepressants applied in psychiatry, supported a common viral pathomechanism, involving reversible disturbances of the neurotransmitter network in the limbic system. Sequences of genetic material amplified from infected animal tissue and human PBMCs revealed a close interspecies relationship and high sequence conservation of the BDV genome. In human BDV isolates, however, single unique mutations were prominent in four genes. This finding supports the hypothesis that despite of high genomic conservation, species-specific genotypes may be definable, provided the sequences are derived from RNA of infectious virus. ( info) |