the antimalarial properties of quinine (Frank, 2000). Illicit drug use also increases the risk for infection with hepatitis A, B, and C, as well as Staphylococcus aureus (Lange, 1989; Kapadia et al., 2002; Chambers, 2001; Ribera, 1998; Tuazon and Sheagren, 1974). The introduction of crack cocaine into New York City in 1985 and the increasing intravenous use of heroin played important roles in the emergence of a variety of infectious diseases, notably tuberculosis and HIV (Garrrett, 1998).

HIV has arguably had the greatest impact on awareness of the dangers of illicit drug use with regard to infectious diseases. People who share drug injection equipment, those who have unprotected sex with injection drug users, and children born to mothers who contracted HIV by sharing needles or having unprotected sex with an illicit drug user are at increased risk for HIV infection. In the United States, injection drug use has been responsible directly or indirectly for more than one-third of all AIDS cases since the epidemic began (CDC, 2002f). More than half of all AIDS cases among women in the United States have been associated with illicit drug use, compared with one-third of cases among men.

Noninjection drug use contributes indirectly to increased transmission of STDs, including HIV, when users trade sex for drugs or money. In addition, crack cocaine use and heroin sniffing have been associated with high-risk sexual behaviors among both men and women (Campsmith et al., 2000; Sanchez et al., 2002). Gay and bisexual men engage in riskier sexual behavior after taking popular club drugs such as methylenedioxymethamphetamine (Ecstasy), ketamine (Special K), and volatile nitrates (poppers) (Mattison et al., 2001; Mansergh et al., 2001). The resulting high-risk sexual behaviors have accounted for the greater prevalence of HIV infection among crack smokers and gay men (Edlin et al., 1994; Schwarcz et al., 2002).

The association between illicit drug use and HIV/AIDS is a worldwide problem. In 1992, only 52 countries reported HIV infection associated with illicit drug use. By the end of 1999, that number had jumped to 114. The most affected regions are Southern and Eastern Europe, Central Asia, North America, East Asia, and Latin America. Up to 90 percent of the registered HIV infections in the Russian Federation have been attributed officially to injection drug use (UNAIDS and WHO, 2002). Even Africa, where injection drug use was once believed not to be a problem, is showing an increased incidence of HIV infection associated with illicit drug use. In a 2000 study of drug injection in Lagos, Nigeria, that was presented at the XIIIth International AIDS Conference, 20 percent of 400 interviewed drug users reported having injected either heroin (63 percent) or cocaine (19 percent); 35 percent of the illicit drug users had initiated at least one person into drug injecting within the past 6 months. Among the illicit drug users, 9 percent were HIV-positive, compared with a national average of 5.4 percent. Fur-



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