The Threat of TB

TB

TB kills someone approximately every 20 seconds — nearly 4,700 people every day, or 1.7 million in 2009 alone, according to the latest estimates from the World Health Organization (WHO). TB is second only to HIV as the leading infectious killer of adults worldwide. It is among the three greatest causes of death of women aged 15-44 and is the leading infectious cause of death among people with HIV/AIDS.

TB is global. The WHO estimates that two billion people — one third of the world's population — are infected with Mycobacterium tuberculosis (M.tb), the bacillus that causes the disease. M.tb's unique cell wall, which has a waxy coating primarily composed of mycolic acids, allows the bacillus to lie dormant for many years. The body's immune system may restrain the disease, but it does not destroy it. While some people with this latent infection will never develop active TB, five to 10 percent of carriers will become sick in their lifetime.

Once active, TB attacks the respiratory system and other organs, destroying body tissue. The disease is contagious, spreading through the air by coughing, sneezing, or even talking. An estimated nine million new active cases develop each year.


At any given moment, more than 13 million people around the world are suffering from an active infection.


Despite enormous advances in provision of services in recent years, TB's deadly synergy with HIV/AIDS and a surge in drug-resistant strains are threatening to destabilize gains in TB control. While incidence is stable or falling in many regions of the world, global rates of new infections are still rising in many endemic areas where TB goes hand-in-hand with HIV/AIDS and the effects of poverty.