Tuberculosis is a killer disease that has stalked humans since at least the Neolithic age: the earliest known death to have been attributed to it dates back about 9 thousand years. But the bacterium that causes it is far older. It is believed to have evolved along with people. And it is still evolving.
About one third of the world's population is infected with the tuberculosis bacillus, but only about 10 percent of them develop the disease. A variety of factors may cause the progression from latent infection to active disease, including, but not limited to, a weakened immune system and becoming sick with other diseases. There is no way to predict with 100% certainty who will progress from infection with the TB bacillus to become sick with active disease.
The discovery last century of diagnostic tests, vaccines and antibiotics led many to consider tuberculosis conquered, or at least under control in most areas of the world. But true to its long history, the disease has mutated to antibiotic-resistant strains. Tuberculosis is usually treated with a 6 to 9 month course of relatively inexpensive antibiotics.
However, the new, drug resistant variants of the disease are much more difficult and costly to treat, and in some cases are untreatable with available antibiotics. These strains of the disease require a whole new effort to develop effective vaccines and medications.
Political commitment to eliminate the threat of tuberculosis is growing world-wide. The United States is at the forefront of the battle, said U.S. Secretary of State Hillary Rodham Clinton. "The U.S. Government is the largest contributor to the Global Fund to Fight AIDS, Tuberculosis, and Malaria, which has detected and treated over 4 million cases of TB.
The President's Emergency Plan for AIDS Relief (PEPFAR) is ... engaged in infection control efforts to prevent new cases of TB. In addition, the United States Agency for International Development (USAID) has tuberculosis programs in more than 35 countries and is working to strengthen the capacity of health systems to identify, detect and control TB, particularly [drug-resistant] MDR and XDR TB," said Secretary of State Clinton.
Tuberculosis is an ancient and difficult enemy of the human race. It will take a strong cooperative effort on a global scale if we are to find ways to fight its new, deadlier forms.