Viral pulmonary
infections are a major cause of morbidity and mortality in solid organ transplant recipients. The herpes viruses-cytomegalovirus, herpes simplex virus, varicella zoster virus, and Epstein-Barr virus--cause most of the
viral infections in this population. Respiratory syncytial virus, adenovirus, and human immunodeficiency virus also cause
pneumonitis in the transplant recipient. Differences in the clinical and laboratory presentation of
pneumonitis due to the various viral agents can provide clues to the etiology. However, definitive diagnosis requires laboratory identification of the virus or appropriate serologic changes. With cytomegalovirus, herpes simplex virus, Epstein-Barr virus, and adenovirus, one must take care to distinguish between asymptomatic shedding of the virus and disease produced by the virus. Advances in diagnostic techniques such as rapid
antigen detection, nucleic acid hybridization, and gene amplification may allow an earlier diagnosis of
viral pneumonia. Advances in risk reduction with appropriate pairing of donors and recipients, improved immunosuppressive regimens, vaccination, and prophylactic administration of
antiviral agents may reduce the incidence of
viral infection. Finally, advances in anti-viral
therapy have made possible the successful treatment of
pneumonia due to some of the viral agents.