Major trends in nosocomial viral infections.

Viruses have recently become appreciated as nosocomial pathogens. There is insufficient data to characterize trends in rates of viral nosocomial infections, but there have been major trends in methodologies and concepts. New groups of patients, such as infants and the elderly, are becoming appreciated as being at risk for serious nosocomial viral infections, whereas other groups, such as immunodeficient patients are expanding because of the epidemic of human immunodeficiency virus (HIV) infection and expanded use of immunosuppressive treatment. The continued addition of new viruses, such as HIV, human parvovirus B19, and rabies virus, to the list of potential nosocomial pathogens suggest that most human viruses can probably be serious nosocomial pathogens under the right circumstances. Advances in medical treatments and procedures, such as cadaveric dura mater grafts and laser treatment of warts, have provided new avenues for nosocomial transmission of viruses. Improved and wider availability of diagnostics promises to be a major force in improving our understanding and ability to prevent viral nosocomial infections. With these advances, viral diagnostic laboratories should become an important member of the infection control team. In parallel with trends in methodologies and concepts, there have been major advances in our understanding of ways to prevent some nosocomial viral infections. Application of these prevention measures is an important challenge to the infection control practitioner.