LONDON – Drug-resistant strains of tuberculosis have reached troubling levels in Eastern Europe and Central Asia and could potentially worsen the global toll from the disease, according to a new report published by two health groups.
The number of new cases of multidrug resistant TB emerging each year is about 300,000, according to the report being released Tuesday by the World Health Organization and the International Union Against Tuberculosis and Lung Disease. In certain areas of Eastern Europe and Central Asia, TB patients are now 10 times more likely to be infected by strains resistant to several standard treatments than in the rest of the world, the report says.
This could pose an eventual health issue for the European Union. Ten new countries are set to become members of the EU in May, and their citizens will face far fewer restrictions when it comes to traveling to current EU countries. Some of the countries that will join -- Estonia, Latvia and Lithuania -- have some of the highest rates of drug-resistant TB in the world.
Any time an infected person travels "it's a public-health worry," said Abigail Wright, a TB expert at the Geneva-based WHO. The TB baccilus is typically transmitted via the air when an infected person sneezes or coughs in the vicinity of others.
Some eight million people world-wide get the active form of TB each year, and about two million die from the disease. In Africa and parts of the former Soviet Union, the disease is increasingly fueled by HIV-co-infection, which weakens the immune system and makes a patient more susceptible to the TB baccilus.
While treating TB is cheap and effective -- a six month course of drugs costs $10 (€8) -- the emergence of so-called MDR, or multidrug resistant, strains has made public-health officials especially anxious. Such cases cost a hundred times more to treat, and even among those patients fortunate enough to get the medicines, some don't survive. About 80% of MDR-TB cases are now deemed to be "super strains" and can resist at least three of the four main drugs used to cure TB.
TB strains develop resistance when a case is improperly or incompletely treated -- either a doctor doesn't prescribe the right treatment, or the patient doesn't stick to the therapy. As a result, TB bacilli that were able to survive the treatment multiply in the patient's body, and the stronger, mutated strains can then be transmitted to other people.
This occurred in the former Soviet Union, a country with a poor history of TB control. Back then, treatment was conducted on an individualized basis and doctors didn't often follow a standardized regimen. After the break-up of the country, the drug supply temporarily was interrupted, another condition that allowed drug-resistant strains to emerge. Data collected in 2002 from the Tomsk region of the Russian Federation show an MDR-TB prevalence rate of 13.7%.
To stem the tide of drug-resistant strains of tuberculosis, the WHO wants more countries to widely adopt a strategy known as DOTS, which requires a doctor, nurse or family member to directly observe a TB patient taking the necessary medicines. Currently, the DOTS strategy reaches only 30% of the world's TB cases, according to the WHO.
Another problem is the lack of a new class of TB drugs; the current treatments are based on compounds invented some four decades ago. Large pharmaceutical companies have long been hesitant about trying to discover new TB drugs, partly because profit margins for such medicines are low and the global market is believed to be only $500 million, according to an estimate by the Global Alliance for TB Drug Development, a nonprofit group based in New York.
The group itself has licensed six TB drugs, but they are all in the preclinical stage of testing and are likely to take six years or more before they will be available commercially. "The fact that we have a portfolio is a quantum leap from five years ago," said Maria Freire, chief executive officer of the TB drug alliance. "But we have a long way to go."