HIV/AIDS

Human Immunodeficiency Virus (HIV), the agent that causes Acquired Immune Deficiency Syndrome (AIDS), is a relatively recently discovered virus. The virus was isolated in 1983 and linked to AIDS in 1984. In 1985 a serologic test was developed to identify HIV, and since then the seroprevalence of the disease in the United States and across the world has been under careful scrutiny. The attention paid to HIV disease and AIDS since its discovery has been exponential, resulting in significant information in HIV virology, its pathogenesis, and treatment. The rate at which information flows within the study of HIV is unsurpassed by any other disease. Because it is a virus that is transmitted sexually, it is mentioned here. However, the following discussion represents only the briefest of introductions into this vast field of study. Any serious student of HIV disease or AIDS need first become well acquainted with human immunology before delving into the subject.

HIV is found in every country of the world. It was estimated that by the end of 1999, over 32.4 million adults were infected with the virus, as well as 1.2 million children. In the U.S., AIDS is the leading cause of death for certain groups of 25 to 44 year- olds. Since HIV is spread through sexual contact and exposure to blood products, characteristics of the AIDS epidemic are directly related to the practice of risky behaviors, such as unprotected sex or injection drug use. In the United States, HIV infection was initially concentrated in the male homosexual population. However the proportion of people newly infected who obtained the infection through

heterosexual contact continues to increase significantly; outside of the U.S., heterosexual contact is the predominant mode of transmission. Mothers also pass the virus on to their children during pregnancy, birth or breastfeeding. Until the blood