The researchers established the existence of asymptomatic infection of Borna disease virus (BDV) in a group of 160 immunocompromised humans. The study meant to only determine existence of BDV infection, not prevalence, and as provide insight into the epidemiology of the disease. The study was conducted in France, where human BDV infection has not been studied, and is particularly interesting because of a lack of symptomatic epidemic animal infections.
Using reverse transcription-nested PCR and hybridization with careful control against contamination, white blood cells from 82 HIV-infected patients and 80 therapeutically immunosuppressed patients were screened for BDV RNA. Researchers discovered that 13.41% of the HIV-infected patients were found to be infected with the virus, while only one out of the therapeutically immunosuppressed group was found to have BDV RNA. This alludes towards major differences in HIV-associated and therapeutically-induced immunosuppression. Also of interest is the fact that none of the infected patients were found to have acute psychiatric symptoms or was previously treated for chronic psychiatric disease, and BDV does not appear to be opportunistically pathogenic. These results call for further research of BDV in humans, especially to establish its prevalence in both immunosuppressed and normal populations.