Herpesviruses

Nine herpesviruses from three subfamilies (α, β, γ) are known to infect humans. The hallmark of herpesvirus infection is the ability to establish latency and reactivate when immunosuppressed. While relatively innocuous in young children, α-herpesviruses (herpes simplex virus, varicella-zoster virus) are the cause of significant morbidity and mortality at the extremes of age and in immunosuppressed individuals, with a significant cost to healthcare systems worldwide. Current treatment, although effective, needs improvement; new vaccines and drugs with novel therapeutic targets offer potential to reduce the burden of disease. Within β-herpesviruses, cytomegalovirus (CMV) is the most clinically significant. Congenital CMV infection is the most common infective cause of sensorineural deafness. It is also a common problem after transplantation. Prophylactic or pre-emptive antiviral strategies have been developed for its management. Chromosomal integration of human herpesvirus 6 is a curiosity. Its significance is not clear but it may have clinical implications. γ-Herpesviruses are lymphotropic and can be associated with lymphoproliferative disorders or malignancies. Management options include treating the underlying immune deficiency if present, use of chemotherapy, B cell depletion and adoptive T cell transfer.