the prevalence of TB in the United States decreased 39 percent from 1992 to 2000 (Bloom, 2002). Today, the majority of TB cases in the United States are among foreign-born persons.
Roughly 2 million people die each year from TB worldwide (WHO, 2002c), with the vast majority of these deaths (98 percent) occurring in developing countries (Mukadi et al., 2001). In 2000, approximately 8.7 million new TB cases were reported, of which an estimated 3 to 4 percent were multidrug-resistant (Jaramillo, 2002). In most countries, the average incidence of TB has recently been increasing approximately 3 percent per year; however, the increase is much higher in Eastern Europe (8 percent per year) and those African countries most affected by HIV (10 percent per year). Twenty-three countries account for 80 percent of all new TB cases. In 2000, over half of these cases were concentrated in five countries: India, China, Indonesia, Nigeria, and Bangladesh. Although Zimbabwe and Cambodia report fewer total cases, they possess the highest global rates per 100,000 population (562 and 560, respectively) (WHO, 2001a). If present trends continue, more than 10 million new cases of TB are expected to occur in 2005, mainly in Africa and Southeast Asia; by 2020, nearly 1 billion people will be newly infected, 200 million will develop the disease, and 35 million of them will die (WHO, 2002a).
The global resurgence of TB is not confined to developing countries. From 1990 to 1995, TB rates in Russia increased by 70 percent, with more than 25,000 persons dying from the disease each year (Netesov and Conrad, 2001). The increased incidence is compounded by the spread of multiple drug-resistant TB (MDR-TB), especially in prisons, where patients typically self-administer treatment. Because most prison clinics experience massive shortages of drugs, most patients are unable to complete their full course of treatment, thus fostering the emergence of MDR-TB. Indeed, the rate of MDR-TB among TB isolates in Russian prisons is an astonishing 40 percent, compared with 6 percent in the general population. The overall rate of TB per capita in prison populations (i.e., including both MDR-TB and other forms of the disease) is nearly 100 times higher than in the Russian population at large.
TB is the leading cause of morbidity and mortality among HIV-infected people worldwide (Mukadi et al., 2001), who are at greater risk of developing the disease (Wood et al., 2000). In 1995, approximately one-third of HIV-infected people worldwide were also coinfected with M. tuberculosis; the vast majority of these cases were in sub-Saharan Africa (Harries and Maher, 1996). The incidence and case-fatality rate (i.e., the proportion of patients who die among those diagnosed) for TB in sub-Saharan Africa has increased dramatically since the HIV epidemic first began (Mukadi et al., 2001). In some sub-Saharan countries, the case-fatality rate for HIV-posi-