Viral Infections in Healthy and Immunocompromised Hosts

Viral infections are an important cause of morbidity and mortality in hospitalized patients as well as out-patients. New strains of viruses may appear and cause epidemics in healthy persons or immunocompromised persons. A better understanding of these new virus strains may help to control and prevent these infections. Some viral infections that would otherwise be asymptomatic or cause mild disease can be life threatening in immunocompromised persons. Immunocompromised persons often shed high titers of virus for prolonged periods of time. In the absence of a potent immune system, viruses may evolve more rapidly in their hosts. Therefore, analysis of sequential virus specimens from these patients can provide information on virus evolution, including how resistance to antiviral agents can develop. In addition, higher titers of virus may be associated with virus mutants that are more adapted to grow in cell culture. In this protocol we will obtain specimens containing viruses from otherwise healthy or immunocompromised patients over sequential periods of time to study their nucleic acid sequences, sensitivity to antiviral agents, cell types infected by the virus, and ability to grow in cell culture. In some cases, we will review tissue biopsies or clinical reports from outside laboratories to assist with the diagnosis of virus-associated diseases. We will also record the patient s signs and symptoms, take a short history or ask patients to fill out a questionnaire, note results of any pertinent laboratory work-up, and in some cases, obtain blood to measure immune responses, isolate antibodies or virus-specific T cells, or to look for viremia. This study will include patients with viral infections and/or receiving viral vaccines. This study should provide further understanding on how viruses evolve in their natural hosts, how they become resistant to antiviral agents, how antibody responses evolve to viruses, and might allow some currently uncultivatable viruses to be grown in cell culture.