Global control of TB threatened by epidemics in key countries
Special Report: TB around the globe
Global control of TB threatened by epidemics in key countries
U.S. cases down, but nearly half of new cases are in foreign-born
Although U.S. cases of tuberculosis declined in 1997 for the fifth consecutive year, health officials warn lack of political will and poor implementation in other countries threaten the global effort to fight a disease that could kill 70 million people in the next 22 years.
The number of new TB cases in this country last year dropped 7% from the previous year - 19,855, compared with 21,327 in 1996. With five years of declines in TB cases, health officials from the Centers for Disease Control and Prevention are confident the TB epidemic that reached a peak in the late 1980s has been thwarted by increased funding, tighter controls, and improved diagnosis and treatment.
Nonetheless, recent success is tempered by the heavy burden of TB disease that originates in people born outside the country. Nearly 40% of U.S. cases of TB are now among people born outside the country, primarily from Southeast Asia, Africa, and Latin America. An estimated one-third of the world population is infected with the TB bacillus, including 50 million who are suspected of being infected with drug-resistant strains.
"In the United States, it may be tempting to rest easy because we appear to have TB under control," says Helene Gayle, MD, MPH, director of the CDC's National Center for HIV, STD, and TB Prevention. "Yet even in this country, we continue to identify cases of multidrug-resistant (MDR) TB. There is no question that the continued spread of MDR-TB internationally could dramatically impact the United States."
In its annual report released on World TB Day, the World Health Organization (WHO) warned that worldwide progress toward TB elimination was stalled in at least 16 key countries (see table, above), raising the likelihood that the agency's control targets for the year 2000 could not be met. The 16 countries are the source of more than half of the world's 7 million annual TB cases, and about half are considered middle or upper-middle income countries. These countries, including Brazil, Thailand, Iran, Mexico, South Africa, and Indonesia, have the financial resources to implement directly observed therapy, short-course (DOTS), but have lacked political will to utilize them, WHO officials point out.
"If we seem impatient in again calling for global action, it is because we have an effective solution to a disease which is needlessly claiming millions of lives," says Arata Kochi, MD, director of WHO's Global Tuberculosis Programme. "The use of DOTS has expanded nearly tenfold in the past five years. Cure rates have nearly doubled. And drug resistance is lower in places where DOTS has been used. But as impressive as this progress may seem, it is simply not enough when compared with the scale of the global epidemic."
Health officials are particularly concerned about the spread of TB in countries with high rates of HIV, particularly in Africa. South Africa now has one of the world's highest rates for both TB and HIV. In addition, poorly managed TB programs in low-income countries have fueled the emergence of drug-resistant TB, Kochi says.
"Some governments did not take WHO's declaration of a global TB emergency seriously," he says. "Countries that did, such as Bangladesh, Vietnam, and Peru are making excellent progress toward controlling TB."
An ad hoc committee convened by WHO recently called world leaders to make definitive efforts toward the global TB epidemic. The committee notes that many world leaders are ignorant of the scope and the cost of the problem, but too many simply lack the political will to target resources. The committee also called for development of a coordinated partnership to fight the global epidemic, bringing together WHO, the World Bank, the International Union Against Tuberculosis and Lung Disease, and bilateral development assistance agencies.
The WHO report was not all negative. TB control has achieved many successes in countries such as Armenia, Cambodia, Cuba, Kenya, Malawi, and Slovenia. DOTS also has been used extensively in large countries such as Bangladesh and China. Additionally, DOTS has begun in 10 of the 16 "trouble spot" countries, including South Africa, the Russian Federation, and Uganda.
Globally, the number of patients on reported DOTS rose from 704,920 in 1995 to 887,731 in 1996, an increase of 26%. Treatment success in areas that implement DOTS is reported at 78%, compared with 45% in non-DOTS patients, WHO reports.
Without better prevention tools, TB will not be controlled, Gayle says. "Given the global burden of TB reported today, a new and effective vaccine is needed. Improved diagnostic tools and new drugs will also be needed to combat drug-resistant strains," she notes, adding that the most recently developed anti-TB drug became available in 1972.
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