Today, there are co-occurring epidemics of human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) among IDUs, largely spread through multiperson use of contaminated injection equip-ment such as syringes and through unprotected sexual intercourse with infected individuals. Between July 1995 and June 1996, over 70,000 new cases of Acquired Immunodeficiency Syndrome (AIDS) were reported in the United States, raising the cumulative total to 548,102 cases (Centers for Disease Control and Prevention [CDC], 1996a). Each year, an estimated 41,000 new HIV infections occur in the United States (Holmberg, 1996), and at least 140,000 HBV infections and 35,000 HCV infections are

estimated to occur (CDC, 1996b). In the year ending 1995, more than a third of all new AIDS cases in the United States were attributable, directly or indirectly, to injection drug use (CDC, 1996a). As of July 1996, the Joint United Nations Programme on HIV/AIDS (UNAIDS) estimates that 21.8 million adults and children were living with HIV/AIDS worldwide (UNAIDS, 1996). Although 75% to 85% of the global burden of adult HIV infections is attributable to unprotected sexual intercourse, injection drug use is a major mode of transmission in many areas of the world. Injection drug use has been reported in 118 countries, and AIDS cases attributed to injection drug use have been reported in over 80 of these countries (Des Jarlais et al, 1995).