Map: TB’s Global Reach
Follow @Evan_WexlerMarch 25, 2014, 9:43 pm ET
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As TB cases declined in the Western world in recent decades, so did the funding to deal with the disease.
But TB, an airborne bug that spreads best when the infected are left untreated in crowded areas, continued to flourish in poorer nations. By 1993, the World Health Organization (WHO) had settled on a cost-effective treatment program known as DOTS — a directly observed treatment consisting of a short course of drugs — that would combat susceptible TB in low-income countries. But over the last several decades TB began to develop resistance to the drugs used to treat it. The DOTS strategy had no means of testing for the new strain of multi-drug-resistant TB (MDR-TB), nor were countries given drugs that would treat it. Left unchecked, MDR-TB began to spread across the globe. A conservative estimate puts the number of cases at about a half-million today. Less than one-quarter of those estimated to have MDR-TB have been diagnosed, according to the WHO.
One of the first indications that DOTS wasn’t always working came in Peru in the 1990s. The Latin American nation had one of the best DOTS-based programs in the world at the time. But then a number of people being treated by the DOTS regimen failed to recover. They got sicker. Some became resistant to even more drugs on the DOTS regimen, and spread that new resistance to others. Some died. At the time, the world health community believed that the drug-resistant bugs were less virulent or transmissible, and that all patients should continue to be treated under the DOTS plan. But later studies showed that wasn’t the case: many had contracted MDR-TB outright from other patients. “There was never any data to support any of those three myths,” said Dr. Paul Farmer, a Harvard Medical School professor of global health and social medicine, and a leading expert on TB. The world health community was “missing the fact that this is an MDR-TB epidemic, not just an epidemic of people not being able to comply with the regimen. That was the tragedy.”
For years, the Soviet Union largely kept its TB problem under control. But when the government collapsed in 1991, so did its health system. “Suddenly, the money stopped,” Margarita Shilova, head of the TB department in Moscow’s Phthisiopulmonology Research Institute, told the WHO later. “There were no drugs, communication with local hospitals broke down as telephones were cut off over unpaid bills… it was impossible to transport patients to hospitals, the system broke down.” She added: “Discipline among patients and doctors — which is key to treating the disease — was no longer there.”
TB quickly became an epidemic, particularly in Russia’s crowded, poorly ventilated prisons. Prisoners contracted drug-resistant strains and either died in prison, or brought their new strains into the community upon release. Alcohol and drug addiction, and homelessness, which compromise immune systems, also allowed TB to fester.
But the Russian government began working to address the problem. In the late 90s, Russian authorities linked up with US-nonprofit Partners in Health to improve testing and treatment for those with MDR-TB. In the pilot city of Tomsk, the program cut the TB incidence rate nearly in half from 2000 to 2012.
The small town of Tugela Ferry was a wake-up call for the international community. In 2005, 53 people in a rural hospital were found to be infected with an extensively drug-resistant strain of TB known as XDR. All but one of them died. More cases were later found throughout the provinces and in neighboring countries. The spread here was different than in Russia, or Peru. Most of those who died at Tugela Ferry also had HIV/AIDS. And because of labor migration patterns throughout southern Africa, TB had easily spread.
“If we looked hard at South Africa, it was clear,” Farmer says. “There’s no way that wasn’t going to explode. You had a collision of three epidemics: TB, HIV and labor migration. How could those not result in an explosive MDR-TB epidemic? And they did.”
The findings of a 2011 study were disturbing: only 1 percent of Indian MDR-TB patients have access to proper treatment. Most people who are infected seek care from unregulated, private doctors who often provide the wrong prescriptions, the study found, fostering drug resistance.
India also has another challenge: In 2011, 15 patients arrived in an Indian hospital who proved completely resistant to all first- and second-line anti-TB drugs. It was the first instance of what Dr. Zarir Udwadia, a leading TB expert and lung specialist, identified as TDR — totally drug-resistant — TB.
India has taken steps to deal with MDR. Now, in several states, patients are given a more advanced test, and if they show resistance to one of the more powerful drugs, they’re placed on a standard treatment for MDR right away through the public health system. It’s still not ideal, Udwadia says, but it’s progress. For now, Udwadia says about half of his patients are improving. The rest have died or abandoned treatment while continuing to spread the disease to their families and communities.
China has a “serious epidemic” of drug-resistant tuberculosis, with the world’s largest number of patients with MDR-TB, according to a 2012 report by the Chinese Center for Disease Control. The Center found that patients were receiving inadequate treatment, which helped to foster drug resistance. But, it said that most new cases of tuberculosis showed some resistance to at least one of the first-line drugs, suggesting that MDR is also spreading on its own. The prevalence of MDR-TB among new patients was nearly twice the global average, the Center said. And XDR-TB was also “widespread.” To fight it, the center said that China needs a stronger plan in place to ensure patients receive proper treatment and follow-up.
“We have managed by a combination of complacency and incompetence to allow this bacillus to mutate to a virtually untreatable form,”
wrote Dr. Zarir Udwadia, one of the world’s leading specialists on TB in a recent assessment of TB worldwide. “Squandering away almost every last available drug, we have, as a result of policy and practice failures, allowed drug-resistant TB to flourish through much of the developing world. We have only ourselves to blame.”
Explore the latest data on TB and MDR-TB prevalence worldwide on the globe to the right.
Source: TB and MDR-TB data from the World Health Organization; population data from the World Bank
The map shows the latest data for each nation collected by the WHO, compared to the national population at the time of each survey. The percentage of MDR-TB is based on WHO country surveys, and is calculated against the amount of new and relapse TB cases.
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