Tuberculosis is an infectious disease caused by Mycobacterium tuberculosis. These bacteria infect about one-third of the world's population, but only an estimated 5%-10% of infected people will develop the active form of tuberculosis in their lifetime. The other 90%-95% of people appear to be able to contain the infection in a dormant/latent state, so that they do not become ill. Because tuberculosis is so prevalent, an estimated eight million people develop active tuberculosis each year, of which 2 million to 3 million die.
The most powerful risk factor for the develop of active tuberculosis after infection with the organism is co-infection with HIV/AIDS. M. tuberculosis and HIV are synergistic partners in crime, as each appears to accelerate the progression of the disease due to the other agent.
Research on tuberculosis at the Centre for the Study of Host Resistance involves genetic approaches to understanding why the disease is not the inevitable consequence of infection. Genomic analysis of the bacteria involved, using DNA fingerprinting and DNA microarray technology, is uncovering regions of the genome that vary between strains, specifically between virulent strains and live attenuated BCG vaccines. Host genetic analysis aims to understand why, faced with the same organism, certain hosts are able to control the infection and avoid disease, while other hosts develop active tuberculosis and then continue the transmission cycle. From a better understanding of host and pathogen factors which determine the outcome of infection, it is hoped that more rational interventional strategies can be developed and implemented.