Human Immunodeficiency Virus Infection in Adults

This chapter discusses the background, prevention, diagnosis, treatment, and prognosis for human immunodeficiency virus (HIV) infection in adults. HIV is a single-stranded RNA retrovirus that causes AIDS. AIDS is defined as HIV infection associated with either a serum CD4+ T-lymphocyte level of less than 200 cells/μL, or with an “AIDS defining condition,” which includes 24 opportunistic infections, and other conditions. HIV infection is typically transmitted via sexual contact, intravenous drug use, exposure to infected blood products, or via perinatal transmission. HIV infection causes the destruction of CD4+ T lymphocytes, which result in profound immunosuppression, and higher rates of certain malignancies, such as non-Hodgkin's lymphoma and cervical cancer. HIV infection is also a chronic inflammatory process that causes cardiac, renal, neurologic, and other comorbidities. Antiretroviral therapy (ART) significantly alters the natural history of HIV, suppresses its effects, preserves immune function, and dramatically improves patient survival.