Over the course of human history — in ancient Egypt, in medieval Europe, in 19th-century North America — tuberculosis has surged and waned, causing pain and death on a massive scale before receding. It was during one period of recession, in 1915, that the New York Times warned of the “pressing” need to eradicate the disease.
“The decline,” cautioned the Times, “has lulled us into a false sense of security.”
A century later, tuberculosis is back — only worse. New, drug-resistant strains of the TB bacteria are spreading worldwide, creating what the World Health Organization (WHO) deems a “global emergency.”
Tuberculosis, a highly infectious disease that destroys lung tissue, has been curable since the 1950s, thanks to the development of antibiotics. Yet TB is currently the leading cause of death from infectious disease worldwide, killing 1.6 million, including 230,000 children. Tuberculosis is the ninth leading cause of death overall, according to WHO.
Each year, 10 million people contract TB, but what really alarms scientists: more than half a million patients are infected by multi-drug resistant TB, known as MDR-TB. This strain of TB is resistant to the two most powerful tuberculosis drugs, isoniazid and rifampicin.
More worrisome, thousands contract an even more severe and deadly TB strain, known as extensively drug-resistant TB (XDR-TB), which resists the more costly and toxic second-line drugs. XDR-TB has been reported in at least 123 countries and comprises about 6% of all drug-resistant TB cases.
Echoing the New York Times in 1915, the United Nations has pleaded for an “urgent global response” to the TB epidemic. But advances in medicine and healthcare delivery have, thus far, proved no match for a disease once known as “consumption” and “the great white plague.”
“You’re facing the valley of death because there’s nothing on the horizon,” warns Paul Farmer, M.D., Ph.D., an infectious disease expert at Harvard Medical School’s Department of Global Health and Social Medicine.
A World Health Organization report minces no words: “The ‘end’ of TB as a major public health problem remains an aspiration rather than a reality.”
As 20th-century drugs become obsolete and global migration fuels TB’s spread, halting tuberculosis in all its forms will require political will, development of new drugs, and technological innovation such as hospital air disinfection.
How MDR-TB Develop
TB becomes drug-resistant when infected patients fail to complete the entire course of treatment or when the treatment regimen is mismanaged. Given the lengthy and complex nature of TB treatment, it is hardly surprising that both scenarios are common.
Treatment for ordinary TB requires a regimen of four drugs over 6 to 9 months; all drugs must be taken in precise doses and at precise times. Patients infected with MDR-TB endure far worse: daily injections for six months, IV infusions for up to two years, a total of 14,000 pills, and side effects as severe as hearing loss, psychosis, and kidney impairment.
Many patients drop out of treatment, allowing their disease to morph into XDR-TB.
In wealthy nations, treatment for MDR-TB costs 5 to 10 times more than standard TB treatment. In countries with fewer resources, treating this strain can cost “literally thousands of times” as much and fails more often than not.
Worldwide, only 25% of people with MDR-TB are enrolled in treatment, and only about 55% are successfully treated while 16% die of the disease.
For XDR-TB, treatment is even more complex and gruelling; only about 30% of patients are successfully treated. As the nonprofit TB Alliance puts it, “XDR-TB is emerging as an extremely deadly and costly global health threat that the world is inadequately equipped to tackle.”
The Global Spread of TB
In generations past, what made TB so threatening was the ease with which the bacteria can spread. Droplets of Mycobacterium tuberculosis are launched airborne when an infected person coughs, sneezes, sings, or even speaks. The droplets can waft in the air for hours and travel via air currents, readily infecting susceptible populations in hospitals, prisons, and other crowded locations.
But today, it’s not just TB bacteria that travel so freely; it’s also the global population.
"The rise in drug resistance is definitely a threat for the whole of Europe because people are mobile,” asserts Swedish physician Marieke van der Werf, M.D., Ph.D., head of TB disease at the European Centre for Disease Prevention and Control. “You see people coming from other countries and bringing drug resistance with them. All countries need to be vigilant."
TB and its drug-resistant forms now afflict significant numbers in India, China, Indonesia, and numerous countries in Europe and Africa. The disease also remains a threat in the United States, where it has long been forgotten by the public. As one U.S. researcher warned, “We cannot delude ourselves into believing that TB has gone away . . . It always looms large.”
A few facts about the global reach of tuberculosis and its drug-resistant forms:
- Of the 10 countries in the world with the highest burden of MDR-TB, nine are in the WHO European Region.
- 88% of MDR-TB cases occur in middle- or high-income countries.
- Worldwide, the TB treatment success rate is about 75%. Six European countries have treatment success rates below 60%.
- Nine European countries have fatal TB outcomes higher than 10%.
- India accounts for about 27% of TB deaths.
- Southeast Asia has one-fourth of the world’s population yet nearly half of TB cases and deaths.
- China has the third largest TB burden in the world, with more than 900,000 new cases per year — 16% of all new cases worldwide.
How to Stop Drug-Resistant TB: New Drugs, Disinfected Air
The World Health Organization aims to halt the TB epidemic by 2030, an ambitious target that will require dramatic reductions in TB deaths and new cases and major increases in MDR-TB treatment success.
To get anywhere near these goals, the world must accelerate its response to the new TB epidemic.
“The gap between need and action is arguably greater for tuberculosis than any other disease of global public health importance,” argues Poonam Khetrapal Singh, M.D., regional director of WHO’s South East Asia region.
Technological breakthroughs are desperately needed, including a vaccine and more effective, less toxic drugs. “We cannot hope to end TB without dramatically shorter, simpler and better treatments,” says Mel Spigelman, M.D., president of TB Alliance.
The Alliance, a not-for-profit network of public and private partners — governments, biotech companies, academic research institutes — was formed to advance TB drug development and has medications in its pipeline, though treatments may be years off.
What can be done more immediately?
One promising strategy is air disinfection in hospitals.
What if those airborne TB microbes could be killed instantly before they had a chance to waft through hospital corridors, lobbies, and cafeterias and be inhaled by vulnerable patients? With the advent of plasma technology, that scenario is now a reality.
Currently deployed European hospitals, ultra-low-energy plasma devices have become an effective — and cost-effective — weapon against a long list of antibiotic-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and, of course, multiple drug-resistant Mycobacterium tuberculosis.
The same technology also kills fungal and viral particles on contact, allowing hospitals to reduce the spread of influenza, norovirus, and other highly infectious diseases.
Of course, it will take far more than new drugs and disinfected air to wipe out tuberculosis. Other critical strategies include:
- Improved diagnosing. TB is simply not on the radar of many doctors, so they fail to order the chest X-rays or lung fluid testing necessary for a TB diagnosis; instead, they may attribute coughing and chest pain to air pollution and prescribe antibiotics or cough syrup. One study found medical practitioners in India failed to provide to follow the standard of care for 65% of patients presenting with symptoms.
- Better training and mentoring for healthcare workers. Many cases of MDR-TB become XDR-TB because the complex and arduous treatment is poorly managed. More substantial training can halt this tragic situation.
- Improved patient access to treatment and follow-up. Nations must dramatically increase TB-related budgets, allowing for more financial and nutritional support for patients and their families.
Modern strains of Mycobacterium tuberculosis have been around for as many as 20,000 years and may have killed more humans than any other microbial pathogen. Famous victims include Egyptian King Tutankhamen, English writer George Orwell, Czech novelist Franz Kafka, and American First Lady Eleanor Roosevelt.
When the cure was developed, in the mid-20th century, scientists were hopeful this “dread disease,” as novelist Charles Dickens called it, would be wiped out in short order.
Scientists today are more realistic but no less hopeful.