Infection with the human immunodeficiency virus: Epidemiology, pathogenesis, transmission, diagnosis, and manifestations

Abstract

The epidemiology, pathogenesis, transmission, and manifestations of infection with the human immunodeficiency virus (HIV) are described, along with the development of diagnostic tests and drugs to combat it. Acquired immunodeficiency syndrome (AIDS) is caused by HIV infection. The syndrome was first reported in 1981, and as of March 31, 1989, nearly 90,000 cases had been reported in the United States alone. Most U.S. adults with AIDS are homosexual or bisexual men; intravenous drug abusers, heterosexuals, hemophiliacs, and blood transfusion recipients account for 17%, 4%, 1%, and 2% of AIDS cases, respectively. HIV is transmitted by sexual, blood, and perinatal routes; infection leads to a profound immunosuppression involving both the cellular and humoral immune systems. The hallmark of AIDS is a quantitative deficiency of T4 lymphocytes bearing CD4+ receptors, to which the virus binds. Monocytes are believed to be the major route of infection into the CNS. There has been rapid progress in the development of sensitive and specific diagnostic tests for HIV infection. The enzyme-linked immunosorbent assay and Western blot test are the most widely used; both are used to detect antibodies to the virus. Two major classes of drugs are under development for use against HIV: antiviral agents and immunomodulatory agents. Thus far only one drug, zidovudine (AZT), has decreased mortality and improved quality of life. Infection with HIV encompasses a broad spectrum of clinical manifestations, from seroconversion to AIDS-related complex to full-blown AIDS. AIDS is a clinical diagnosis based on the presence of recurring opportunistic infections, previously rare cancers, and neurologic manifestations. Because of the many people infected and the long incubation periods, AIDS will continue to be a major issue in health care. Continued education of health-care personnel and the public is needed.