Bad And Good News About The Second Deadliest Infectious Disease

Ebola has rightly gripped the world's attention, but its death toll pales in comparison to other infectious diseases like tuberculosis. TB is the world's second leading infectious killer, after HIV/AIDS, and it's claiming more victims than previously thought — 1.5 million last year alone — according to a report released today by the World Health Organization.

Tuberculosis is an infectious disease that typically attacks the lungs but can also affect other parts of the body such as the kidneys, spine and brain. It spreads when infected people expel bacteria by coughing, sneezing or even just talking, especially in confined spaces like airplanes or prisons.

The report says an "unacceptably high" number of lives are being lost to this curable disease. The death toll represents "roughly one sixth of all cases last year," says Dr. Mario Raviglione, director of WHO's global TB program. "We are also hearing that because of the Ebola outbreak in western African countries many people are hesitant to attend hospitals or polyclinics because they fear getting infected with Ebola."

Here's a glimpse of the concerns — and the glimmer of hope — from the 2014 Global Tuberculosis Report:

Better reporting has led to grimmer numbers.

There were an estimated 9 million cases in 2013 — 6 percent higher than experts had thought they'd see. Improvements in reporting in Nigeria, for example, resulted in roughly half a million additional reported cases last year, and a mortality rate in the African region 44 percent higher than the year before. TB numbers are expected to rise further as more countries improve their reporting.

Numbers may be up, but 86 percent of reported cases last year were successfully treated.

There is good news in the report: Effective diagnosis and treatment saved some 37 million lives between 2000 and 2013. Globally, the TB mortality rate fell by an estimated 45 percent between 1990 and 2013 and the total number of cases fell by 41 percent during the same period.

There are still millions of unreported cases.

TB is highly curable when reported and properly treated. Unreported cases amount for some 3 million of the 9 million estimate, Raviglione tells Goats and Soda. He calls them the "missing cases" and says "if you understand why they are missing then you understand why they are dying." These are people who might live in rural areas far from hospitals or who turn to private or traditional healers who don't always follow international treatment standards.

We're better at diagnosing multidrug-resistant TB (MDR-TB) than at fighting it.

"This is the most disturbing part of the findings," says Raviglione. Better reporting methods have led to the diagnosis of an estimated 480,000 new MDR-TB cases last year. but there are not enough health care resources to care for the newly diagnosed. "So we are left with waiting lists" of some 39,000 people awaiting treatment, he says. MDR-TB occurs when strains of the disease become resistant to the drugs commonly used to treat TB, usually because of improper use of antibiotics or patients' interrupting the strict, six-month drug regimen. Drug-resistant forms can also be transmitted.

More than half of the world's MDR-TB cases are in India, China and Russia.

But those countries are not alone. Some Eastern European and central Asian countries have extremely high levels of MDR-TB — about 35 percent of their new TB cases. Some 9 percent of these cases are even more difficult to treat because the patients have developed XDR-TB, or extensively drug resistant TB. XDR-TB has been detected in 100 countries and can arise when the second-line drugs used to treat MDR-TB are also misused and become ineffective. Treatment options are seriously limited for these individuals.

HIV and TB are "co-epidemics"

Turns out the world's top two infectious killers are bedmates. People living with HIV are 29 times more likely to develop TB than those who are HIV-negative, says the report. The HIV epidemic beginning in the 1980s led to a major upsurge in TB cases and TB deaths, especially in parts of Africa. Last year, 13 percent of TB patients were HIV-positive, as were a quarter of those who died of TB. Experts are calling for more HIV testing among TB patients and greater access to antiretroviral therapy, which the report says is "the best intervention to reduce mortality among HIV-positive TB patients."