Rare and Emerging Viral Infections in the Transplant Population

Viral infections account for a large proportion of emerging infectious diseases, and the agents included in this group consist of recently identified viruses as well as previously identified viruses with an apparent increase in disease incidence. In transplant recipients, this group can include viruses with no recognized pathogenicity in immunocompetent patients and those that result in atypical or more severe disease presentations in the immunocompromised host. In this chapter, we begin by discussing viral diagnostics and techniques used for viral discovery, specifically as they apply to emerging and rare infections in this patient population. Focus then shifts to specific emerging and re-emerging viruses in the transplant population, including human T-cell leukemia virus 1, rabies, lymphocytic choriomeningitis virus, human bocavirus, parvovirus 4, measles, mumps, orf, and dengue. We have also included a brief discussion on emerging viruses and virus families with few or no reported cases in transplant recipients: monkeypox, nipah and hendra, chikungunya and other alphaviruses, hantavirus and the Bunyaviridae, and filoviruses. Finally, concerns regarding infectious disease complications in xenotransplantation and the reporting of rare viral infections are addressed. With the marked increase in the number of solid organ and hematopoietic stem cell transplants performed worldwide, we expect a corresponding rise in the reports of emerging viral infections in transplant hosts, both from known viruses and those yet to be identified.