Tuberculosis (TB) causes about eight million new infections each year and up to three million deaths. Already one of the leading causes of death world-wide, the number of deaths from tuberculosis continues to increase as new, antibiotic resistant strains and co-infections linked to HIV emerge. A third of the world population has been exposed to Mycobacterium tuberculosis, the bacteria that cause TB. The disease is spread from one person to another, when someone with TB coughs or sneezes and people nearby breathe in the bacteria and become infected. TB most commonly affects the lungs, attacking and destroying tissue, but also can spread to other parts of the body. Despite its prevalence and long history, little is known about the survival of the pathogen in macrophages. Dr. Horacio Bach is studying how proteins secreted by TB bacteria enable them to evade the body’s immune defenses and survive to multiple inside host cells. This research should help explain the cellular mechanisms involved in causing the disease, and could lead to new therapies for controlling tuberculosis bacterial infections.