What's good for the host is good for the bug.

Tuberculosis, caused by Mycobacterium tuberculosis, kills approximately two million people each year. The infection is characterized by an inflammatory response culminating in the formation of a granuloma, a collection of immune cells that controls the infection. However, the granuloma can be the source of immunopathology that encourages transmission. Recent data support the idea that mycobacterial products can positively and negatively regulate the inflammatory response. Our contention is that induction of the immune response and subsequent granuloma formation is beneficial to the host for control of infection, and is also beneficial to the bacillus, as a place to hide and as a means for transmitting the infection to naive hosts.