Drug resistant tuberculosis is expected to increase globally over the next two decades.
New research predicts a steady rise in TB cases that can't be cured with conventional, first-line antibiotics in four countries.
Researchers from the Centers for Disease Control and Prevention forecast that these complicated — and potentially deadly — cases of TB will become far more common in Russia, India, the Philippines and South Africa by the year 2040.
"Multi-drug resistant TB is going to increase to about 30 percent of cases in Russia," says Peter Cegielski with the CDC's Global TB Branch and the senior author of the new report. "It [drug resistant TB] will get to about 10 percent in India and the Philippines and probably about 5 percent in South Africa."
These four countries already have the bulk of the world's drug resistant tuberculosis. Because the disease is highly contagious, things look like they're going to get worse before they get better, even with major efforts to curtail the spread. Last year according to the World Health Organization, there were more than 10 million new cases of TB (both drug-resistant and regular) globally and nearly 2 million TB-related deaths.
Even the simplest cases are difficult to treat.
"Plain TB is curable with six to nine months of treatment," says Cegielski at the CDC. "Treatment rates for multidrug resistant TB and extensively drug resistant TB are far worse. Mortality rates for MDR are around 30 percent and as high as 80 percent for XDR. That's worse than most cancers."
Treatment for drug resistant TB can take up to two years, involve daily injections of highly toxic drugs and can come with severe side effects including psychosis and hearing loss.
Some new strains have emerged that aren't treatable at all. These cases are labeled "totally drug resistant" because the infections don't respond to any available antibiotics. The fatality rate is 100 percent.
Part of what's terrifying about tuberculosis — and particularly drug-resistant TB — is that the bacteria spread through the air. Someone with TB can cough in a room and potentially infect many other people.
"It's airborne [and] bacilli can remain suspended in the room for hours depending on the ventilation," says Cegielski. "So anybody in the room can be exposed and infected. And it doesn't have to be a room, it can be any enclosed environment — a store, a bus, any place like that."
Because treatment is so complicated Cegielski says there needs to a lot more attention to preventing new infections in the first place.
"Airborne infection control in most countries, particularly in hospitals and clinics, is rudimentary at best or even non-existent," he says. "It's really only practiced in affluent countries."