Via The Guardian, a November 14 op-ed by Dr. Tedros Adhanom Ghebreyesus: Why is the world losing the fight against history's most lethal disease? Excerpt:
Tuberculosis has killed more people than any other disease in history. Last year, 1.5 million people died from TB and 10 million more acquired it. A shocking one-quarter of the world’s population is infected. That’s not much better than 1993, when one-third of the world was infected and the World Health Organization declared TB a global emergency. We are losing the battle.
Earlier this month, experts gathered in Hyderabad for the 50th Union World Conference on fighting the disease. When the first such gathering was held in 1867, TB was the leading cause of death in industrialised nations. Today, it still ranks in the top 10 worldwide. Why, despite all the progress in medicine and public health over the past 150 years, is TB still the most common and lethal of all infectious diseases?
First, TB has a singular capacity for contagion. When someone with active TB coughs or sneezes, they launch respiratory droplets containing the bacteria into the air. These droplets can stay suspended for hours, turning shared spaces – homes, schools, public transport, hospital waiting rooms – into transmission hot spots. And unlike some diseases, such as measles, which can be caught only once, this “smart” pathogen can cause disease multiple times.
But easy as TB is to catch, it is hard to diagnose. Once someone is infected, either the body’s immune system defeats it, it becomes dormant (latent TB) or it develops into the active disease.
The chief symptoms – cough, fever, and weight loss – come on slowly and are common to many other diseases.
Most diagnostic tests are more than a century old and not very effective. Sputum microscopy has been used since Robert Koch discovered Mycobacterium tuberculosis in 1882. It only picks up half the cases of active TB. The skin, or Mantoux, test, also dating from the 19th century, which can detect latent TB, doesn’t pick up anything for two months after exposure.
Modern, more accurate tests are prohibitively expensive. Bacterial culture, the gold standard, takes weeks for results. False negatives or long waits delay getting people into treatment; when they are, it takes just 72 hours for them to stop being infectious.
