SENSITIVITY AND REPRODUCIBILITY OF RT-PCR TO DETECT BORNA-DISEASE-VIRUS (BDV) RNA IN BLOOD - IMPLICATIONS FOR BDV EPIDEMIOLOGY

Borna disease virus (BDV) infection of domestic animals and humans app ears to have a worldwide distribution. There is evidence suggesting an association of BDV with certain psychiatric disorders, However, more comprehensive epidemiological studies are required to establish rigoro usly a link between BDV and human mental disorders, and to evaluate th e role of carrier animals as potential source of BDV for human infecti on. The use of RT-PCR to detect BDV RNA in peripheral blood mononuclea r cells (PBMCs) of infected individuals is a powerful tool to address these questions. The comparison of discrepant results reported by diff erent investigators using this approach is hampered by the lack of con trols to assess the sensitivity and reproducibility of the assays. Pro cedures are now described that allow the establishment of standardized controls to evaluate the performance of the RT-PCR assays. This RT-PC R assay detected reproducibly 100 copies of BDV p40 RNA in 5 mu g of R NA. The data illustrate that the number of PBMCs used for RNA preparat ion, rather than the amount of RNA, has a critical influence on the ou tcome of the RT-PCR assay. Evidence is provided that levels of BDV in blood do not necessarily reflect viral load in brain. (C) 1998 Elsevie r Science B.V. All rights reserved.