Rare, unusual, and less common virus infections after organ transplantation

Purpose of review: The present article reviews the epidemiology, clinical presentation, prevention, and management of rare, unusual, and less common viruses that infect transplant recipients. Recent findings: Infection may be acquired as a result of natural transmission, reactivation of latent virus, or transmission through the allograft or blood transfusion. The epidemiology, clinical manifestations, and management of these viruses vary widely. Some viruses such as human herpesviruses 6 and 7 are ubiquitous in humans, but they rarely cause clinical disease after organ transplantation. Likewise, adenoviruses, parvoviruses, and some polyomaviruses are commonly transmitted infections in the community, but they cause clinical syndromes rarely in transplant recipients. Other viruses, such as human herpesvirus 8 and hepatitis E virus, are geographically restricted, and cause clinical disease mainly in areas of endemicity. Arenaviruses, including lymphocytic choriomeningitis virus, and rabies virus are two rare viral infections that could be transmitted through transplantation, and they cause an almost invariably fatal illness. Diagnosis of these infections is often delayed as these rare and uncommon viruses are not often considered during the initial stages of clinical investigation. Treatment almost invariably includes reductions in immunosuppression as a result of lack of effective antiviral drugs for most of these viruses. Summary: Transplant recipients are predisposed to develop severe and occasionally fatal clinical illness because of a variety of rare, unusual, and less common viruses. To optimize treatment and outcomes, these pathogens should be considered early on as potential causes of viral syndromes in transplant recipients.