Tuberculosis (TB) is an infectious bacterial disease which most commonly affects the lungs. It is caused by mycobacteria (Mycobacterium Tuberculosis, Bovis, Africanum, Canetti, Microti) which spread through the air when carriers cough, sneeze or spit. It is a disease of poverty affecting mostly young adults in their most productive years.
It is estimated that 1 in 3 people worldwide have been exposed to TB and carry the bacteria somewhere inside their body, accounting for 2 billion people, with almost 9.4 million new cases in 2009. TB is the third-leading cause of death in the world among ages 15-59 (second from infection), causing approximately 1.7 million deaths annually, equal to 4700 deaths a day (WHO, 2009).
The vast majority of TB deaths are in the developing world. Occupancy density, room volume and air change rate are directly correlated with number of new TB infections among persons who share airspace.
Presence of mold and fungi in homes is associated with suppressed T-cell production, which has been linked to slower recovery from TB.
Poor/inadequate ventilation has been shown to be one of factors responsible for emergence of multidrug-resistant TB (MDR-TB) which is a form of TB that is difficult and expensive to treat and fails to respond to standard first-line drugs. According to WHO, in 2008 there were an estimated 440,000 new MDR-TB cases emerging worldwide.
The threat of new TB infections can be reduced by 75% by controlling the airborne capacity of Mycobacterium Tuberculosis infected aerosol, through adjustments of relative indoor humidity and ventilation flow rates.
Tuberculosis quick facts:
• The risk of developing TB is estimated to be between 20-37 times greater in people living with HIV than among those without HIV infection.
• An estimated 1.7 million people died from TB in 2009, the highest number of deaths was in the Africa region.
• Left untreated, each person with active TB disease will infect on average between 10 and 15 people every year.
Source: WHO, November 2010