HIV/AIDS- A PUBLIC HEALTH CHALLENGE

HIV/AIDS- A Public Health Challenge

HIV/AIDS- A Public Health Challenge

Introduction

The human immunodeficiency virus (HIV) causes a chronic, progressive, immune deficiency disease, the most severe phase of which is Acquired Immune Deficiency Syndrome (AIDS). HIV is a newly characterized human retrovirus transmitted only by direct exposure to blood or blood derivatives, certain acts of sexual intercourse, or transfer from infected mother to fetus or infant. In this article the author reviews the most important current epidemiologic, clinical, and virologic information about HIV and HIV disease and provides a factual framework for understanding the issues created by the epidemic.

The human immunodeficiency virus (HIV) causes a chronic, progressive immunologic deficiency disorder called HIV disease (Volberding, 1989). HIV disease is manifest in a spectrum of conditions (Farizo, Buehler, Chamberland, et al., 1992) with highly variable expression, but with a general consistency of pattern and features. The symptoms and signs of HIV disease occur in a sequence of predictable phases, or stages, which eventually culminate in the development of a severe deficit of immune competency that threatens both quality of life and survival. This most advanced phase of HIV disease is called Acquired Immune Deficiency Syndrome (AIDS). HIV has become a critical reason for premature mortality among both male (Buehler, Devine, Berkelman, & Chevarley, 1990) and female (Centers for Disease Control, 1991; Chu, Buehler, & Berkelman, 1990) adolescents and young adults in the United States.

Table 1: HIV prevalence †, AIDS incidence‡, and mortality from AIDS by country, 1999.

How the Challenge being Addressed for HIV/AIDS Prevalence

HIV is a novel human retrovirus, first identified in 1983-1984 in France and the United States, some 3 years after the original description of the first cases of AIDS. Originally named Human T-Cell Lymphotropic Virus, Type III (HTLV-III) in this country (Gallo, Salahuddin, Popovic, et al., 1984) and Lymphadenopathy-Associated Virus (LAY) in France (Barre-Sinoussi, Montagnier, Dauguet, et al., 1983), the virus acquired its current name as a result of an international conference agreement in 1985. HIV, like other retroviruses, contains genetic material composed of ribonucleic acid (RNA); to insert itself in the chromosomes of human host cells (a required step in its life cycle), HIV retroviral RNA must be converted into deoxyribonucleic acid (DNA) by a unique enzyme called reverse transcriptase. This conversion reverses the usual process, in which viral DNA is "read" into RNA, and because the translation of the viral genome proceeds in the opposite direction from usual, the virus is called a retrovirus.

The etiologic association of HIV with the disease that now carries its name, and therefore with AIDS, is well established (Baltimore & Feinberg, 1989; Barre-Sinoussi, et al., 1983; Gallo et al., 1984; Levy, Hoffman, Kramer, et al., 1984). Controversy persists about the effectiveness of HIV in impairing or destroying immunologically capable cells in humans, and, therefore, about whether HIV is sufficient by itself to cause AIDS; some researchers have proposed the existence of a variety of different microbiologic co-factors that might potentiate or augment the effect of ...