| Abstrakt: |
Simple Summary: Fatal cases of encephalitis caused by Borna disease virus 1 (BoDV-1) have been increasingly reported. BoDV-1 causes animal Borna disease, an epidemic condition in pets and animals, with very high animal lethality, but very little is known about the clinical features of human encephalitis cases due to BoDV-1. The appropriate management of BoDV-1 cases requires a timely differential diagnosis from autoimmune encephalitis cases, whose treatment is based on the administration of immunosuppressive drugs that would be otherwise detrimental in viral encephalitis. Therefore, an up-to-date knowledge of BoDV-1 encephalitis clinical features is crucial for an appropriate and timely differential diagnosis. This review was meant to summarize all the available evidence on published cases of BoDV-1 encephalitis cases. Human cases of fatal encephalitis caused by Borna disease virus 1 (BoDV-1) have been increasingly reported. We envisaged the present systematic review in order to provide a comprehensive summary of clinical features associated with BoDV-1 encephalitis. Systematic research of four databases (PubMed, EMBASE, MedRxiv, BioRxiv) was performed during July 2023, and corresponding clinical and epidemiological data were collected and analyzed. A total of 37 BoDV-1 encephalitis cases from 15 different study cases and two countries (Germany, No. 35; France, No. 2) were detected, and their features were summarized (case fatality ratio, 91.9%). Age distribution followed a "U-shaped" distribution, with a first peak in individuals younger than 14 years (18.9%) and the second one in subjects older than 50 years (43.2%). Environmental risk factors were irregularly reported, but 17 out of 37 cases either lived in rural areas or reported repeated outdoor activities (45.9%). Interaction with pets and livestock was reported in eight cases (21.6%), stressing the zoonotic potential of BoDV-1 infections. Moreover, 16.2% of cases were reported among recipients of solid organ transplantations (five kidneys; one liver). Overall survival in children/adolescents vs. adults (≥18 years) was not significantly different (Hazard Ratio 0.878; 95% Confidence Interval from 0.366 to 2.105). Magnetic Resonance Imaging identified the involvement of basal ganglia, mostly of the caudate nucleus (42.4%) and thalamus (33.3%). Cerebrospinal fluid was often characterized by pleocytosis (78.4%). On the other hand, no distinctive clinical features were identified: initial symptoms were specific and included headache, fever, and confusion. In conclusion, BoDV-1 infection can result in fatal encephalitis, whose actual burden still remains unascertained. As the epidemiology of BoDV-1 is similarly elusive, encephalitis cases of unclear cause should be routinely tested for bornaviruses. [ABSTRACT FROM AUTHOR] |
