A Cluster of Fatal Tick-borne Encephalitis Virus Infection in Organ Transplant Setting

Background. Tick-borne encephalitis virus (TBEV) infection has become a major health problem in Europe and is currently a common cause of viral brain infection in many countries. Encephalitis in transplant recipients, althrough rare, is becoming a recognized complication. Our study provides the first description of transmission of TBEV through transplantation of solid organs. Methods. Three patients who received solid organ transplants from a single donor (2 received kidney, and 1 received liver) developed encephalitis 17-49 days after transplantation and subsequently died. Blood and autopsy tissue samples were tested by next-generation sequencing (NGS) and reverse transcription polymerase chain reaction (RT-PCR). Results. All 3 recipients were first analyzed in autopsy brain tissue samples and/or cerebrospinal fluid by NGS, which yielded 24-52 million sequences per sample and 9-988 matched TBEV sequences in each patient. The presence of TBEV was confirmed by RT-PCR in all recipients and in the donor, and direct sequencing of amplification products corroborated the presence of the same viral strain. Conclusions. We demonstrated transmission of TBEV by transplantation of solid organs. In such a setting, TBEV infection may be fatal, probably due to pharmacological immunosuppression. Organ donors should be screened for TBEV when coming from or visiting endemic areas.