Impact

Tuberculosis, commonly called TB, is a contagious disease caused by the bacterium Mycobacterium tuberculosis. The bacteria can attack any part of the body, but usually infects the lungs. Tuberculosis of the lung, or pulmonary TB, is spread through the air by coughing, talking or sneezing. Left untreated, each person with active TB disease will infect on average between 10 and 15 people every year. The risk of infection is related to the proximity and the duration of exposure to the source patient. Decreased ventilation in crowded and confined environments is often a contributing factor. People with TB can be treated and cured if they seek medical help, but the course of treatment is long and complex. And multi-drug-resistant tuberculosis has emerged as a crucial threat due to inconsistent or partial treatment. Today, co-infection with HIV is accelerating the spread of TB because HIV weakens the immune system. Both the highest number of deaths and the highest mortality per capita occur in Africa, where HIV has led to rapid growth of the TB epidemic, and increases the likelihood of dying from TB.

Symptoms

Symptoms of tuberculosis depend on where in the body the bacteria are growing. In the lungs, M. tuberculosis may cause a bad cough that lasts longer than two weeks, pain in the chest, fatigue, fever, loss of appetite and coughing up blood. Tuberculosis is a contagious disease, spreading through the air like the common cold. Only people who are sick with pulmonary TB are infectious. When infectious people cough, sneeze, talk or spit, they propel TB germs, known as bacilli, into the air. A person needs only to inhale a small number of these to be infected.

Seattle BioMed’s Role

In 2002, Seattle BioMed initiated the Pacific Northwest Tuberculosis Straining Typing Center in order to assist the Seattle King County Public Health Department in pinpointing the origins of local TB outbreaks. This rapid diagnosis aided the health department in 2003 when King County suffered its biggest surge in TB in 30 years.

Seattle BioMed is currently focused on two broad goals: a better understanding of the biology of TB disease, and discovery of better, faster TB drugs. Though M. tuberculosis was the first microorganism that was proven to be the causative agent of a disease (in 1882), precisely how it causes disease remains largely a mystery. Seattle BioMed is studying the virulence factors of M. tuberculosis and the host response to infection in order to understand how the interplay and balance of the two results in TB disease. In particular, we are interested in the factors that lead to the phase of TB known as latency, when a person harbors live M. tuberculosis but remains completely symptom-free – though at constant risk of reactivation to active TB disease. As we learn more about how disease occurs, we will be better able to tailor our drug discovery efforts in order to design therapies that thwart specific mechanisms that lead to infection and disease. 

Seattle BioMed recognizes the pressing need for new drugs – drugs that work faster and better, are effective at treating drug resistant strains, and are compatible with HIV-treatments so that co-infected patients may be cured. Because of this urgency, we are not waiting for new biological insights, but are forging ahead with drug discovery efforts based on the best information we have today. As new biological data are generated, they are incorporated to improve our methods. Our current drug discovery efforts include investigation of novel drug targets, screening compounds to identify inhibitors of M. tuberculosis, and development of novel assays for new drug screens.