HIV/AIDS

HIV/AIDS

HIV/AIDS

Introduction

AIDS (acquired immunodeficiency syndrome) presents as a variety of diseases and illnesses, all of which result from infection by the human immunodeficiency virus (HIV). HIV attacks the human immune system, weakening the response of the body to infection and disease and rendering a patient susceptible to various illnesses. HIV causes few symptoms, and an infected person may appear and feel healthy for years after contracting the virus. Once the virus has weakened the immune system sufficiently, the disease progresses to full-blown AIDS, which is marked by a variety of illnesses from which the patient has increasing difficulty in recovering. Death from AIDS results from the effects of secondary illnesses.

Background

HIV/AIDS is believed to have arisen in western and central Africa in the mid-twentieth century. The virus is transmitted through bodily fluids such as blood, semen, and vaginal secretions (Alexandrova, 2004). It is communicated primarily through sexual contact but also can be transmitted from mother to child (prenatally, during delivery, or during breast-feeding), through the sharing of contaminated needles by intravenous drug users, through the use of infected blood in medical procedures, and by other means of blood contamination (needle punctures, contamination of open wounds, etc) (Macfarlane, 2008).

HIV is a retrovirus capable of rapid mutation that produces a latent infection that develops over a long period. To infect a human, HIV must attach to specific host cells known as CD4 cells, which are responsible for regulating the immune system. Once it has occupied a host cell, the virus copies the DNA of the cell, rendering it invisible to the body's defense system. The virus replicates itself within the cells, producing numerous virus particles that bud from the surface of the cell, destroying the cell and moving on to attach to another CD4 cell. For several weeks or months after initial infection the patient is highly infectious, although HIV testing will not reveal the patient's positive status. After this initial period, which is known as the window period, the virus incubates, destroying many CD4 cells but being fended off by the immune system (Macfarlane, 2008). Some two million CD4 cells are destroyed each day by some ten billion newly produced virus particles. The incubation period for HIV is quite long, averaging around ten years. Once the balance between CD4 cells and virus particles shifts in favor of HIV, however, symptoms begin to appear (Wagner, 2008).

In the United States the diagnosis of AIDS is tied to CD4 counts as well as to secondary symptoms. When an HIV-positive individual's CD4 counts falls below 200 (a healthy person's count appears to range from 500 to 1,600) or when that person is determined to have any one of twenty-six opportunistic infections, a diagnosis of AIDS is made. In less developed or poorer countries, however, means for testing CD4 counts are often unavailable or prohibitively expensive. In such cases doctors rely on clinical examination of the patient to make the diagnosis (Robertson, 2006). Certain infections, including tuberculosis and meningitis, are particularly common in HIV-positive individuals(Alexander, ...