Regional increases in the prevalence of multidrug resistant tuberculosis (MDR-TB) underscore the need for developing new TB treatments, as reported in a 1World Health Organization report released March 16.
In addition to raising awareness about the need for focused anti-TB drug research and development, the prevalence data raise "key questions that cannot be answered through routine surveillance," the report - prepared by the WHO/International Union Against Tuberculosis and Lung Disease Global Project on Anti-Tuberculosis Drug Resistance Surveillance - states.
"Operational research should be carried out to determine, amongst other things, the impact of HIV on the transmission of MDR-TB in certain settings, the impact of amplification of resistance at both the individual and population level, and the impact of private sector treatment policies on drug resistance," report authors urge.
Eastern Europe reported the highest prevalence of MDR-TB among new cases, and figures from former Soviet Union countries indicate the problem is of "serious magnitude [and] extremely widespread." Kazakhstan and Israel both had an MDR prevalence rate of 14.2%, the highest from the countries included in the project's data collection activities between 1999 and 2002, the period most recently reported. Other high prevalence areas include Uzbekistan (13.2%), Estonia (12.2%), and China's Liaoning Province (10.4%).
The global surveillance project began in 1994; the 2004 report is the third to be published by the WHO/ IUATLD collaboration.
The document notes from 1994 to 2002, the project surveyed areas representing more than one-third of notified cases worldwide. Based on observed associations between drug resistance, the scope of national TB control programs and the ability to conduct resistance surveys in a given country, the authors predict the problem is likely to be serious in some unsurveyed countries, such as Bangladesh.
Former Soviet countries with low survey coverage should undertake "proficiency testing of national reference laboratories," the report recommends, since "one of the identified obstacles to surveillance in the region is the lack of internationally quality-controlled laboratories."
WHO also points out Eastern Europe's growing MDR-TB problem overlaps with the regional HIV epidemic, which the United Nations deems the "world's fastest-growing" (2"The Blue Sheet" Feb. 23, 2004, p. 20).
The report's findings "emphasize the importance of strengthening TB control worldwide, by expanding [Directly Observed Treatment Short-Course] in order to prevent the emergence of further drug resistance."
Moreover, WHO guidelines for re-treating MDR-TB patients "should be re-evaluated in some settings and...revised if necessary," the report recommends.
Speaking at a same-day event, Global Alliance for TB Drug Development CEO Maria Freire, PhD, stressed even in implementing DOTS and DOTS-Plus, "we really are talking about using drugs that have been developed at least 30 or 40 years ago." She questioned why this situation is acceptable for TB, when it would be "incomprehensible" for society to accept treating cancer or diabetes with such outdated regimens.
"These tremendous strains of resistant tuberculosis around the world are really a direct reflection that we are not using the kinds of tools that...should be made available to people in the field," Freire maintained. In absolute numbers, the WHO/IUATLD project estimates 300,000 new cases of MDR-TB emerge each year globally. At least one-third (2 bil.) of the world'#39;s population is infected with tuberculosis bacteria.
National statistics released in the March 19 CDC Morbidity and Mortality Weekly Report, coincident with World TB Day (March 24), show the 2003 incidence of drug resistance in new U.S. cases was highest in foreign-born patients, with a prevalence of 1.2%. New tuberculosis cases diagnosed in U.S.-born patients had an MDR prevalence of 0.6%, CDC reports.
Evaluating national five-year trends, CDC notes an increase in TB among foreign-born persons, who accounted for 53.3% of all U.S. cases in 2003, in comparison to 41.7% in 1998. Also striking is the fact the 2003 TB rate in the foreign-born population is 8.7 times greater than the rate in those U.S.-born (23.4 versus 2.7 cases per 100,000 persons).
Close to 15,000 new TB cases were reported to CDC during 2003, a 1.4% decrease in cases from 2002.