TUBERCULOSIS
Definition
Tuberculosis (TB) is an infectious bacterial disease of humans and animals caused by a germ called Mycobacterium tuberculosis. TB most commonly affects the lungs (pulmonary tuberculosis) but also can affect other parts of the body (extrapulmonary tuberculosis), such as the brain, lymph nodes, kidneys, bones and joints.
TB is characterized by the formation of tubercles on the lungs and other tissues of the body, often developing long after the initial infection when the tubercle bacilli in the body have started to multiply and become numerous enough to overcome the body’s defenses.
Causes
Prevalence
Year: 1993
World Health Organization (WHO) declared tuberculosis a global emergency.
With the spread of AIDS, tuberculosis continues to lay waste to large populations. The emergence of drug-resistant organisms threatens to make this disease once again incurable.
Year: 1995
3 million people died from TB. M. tuberculosis continues to kill millions of people yearly worldwide.
Year: 2004
WHO estimates that there were 8.9 million new cases of TB, including 3.9 million new smear-positive cases.
An estimated 1.7 million people died from TB, including those co-infected with HIV.
1in 10 people with the TB bacilli will become sick with active TB in their lifetime; the risk is even higher for patients with HIV/AIDS.
Most infections in humans result in an asymptomatic, latent infection, and about one in ten latent infections eventually progresses to active disease, which, if left untreated, kills more than 50% of its victims.
Year: 2005
Estimated 1.6 million people worldwide died of TB
Year: 2006
There were 1,256 new cases of tuberculosis reported among Singapore residents in 2006 compared to 1,712 cases in 1997, giving an incidence rate of about 35 per 100,000 population.
Year: 2007
There were an estimated 13.7 million chronic active cases, 9.3 million new cases, and 1.8 million deaths More than 90% of TB cases occur in developing nations that have poor resources and high numbers of people infected with HIV.
More people in the developed world are contracting tuberculosis because their immune systems are compromised by immunosuppressive drugs, substance abuse, or AIDS
The distribution of tuberculosis is not uniform across the globe; about 80% of the population in many Asian and African countries test positive in tuberculin tests with the highest rates per capita (29%) are seen in Africa; about half of all new cases of TB appear in 6 Asian countries (India, Pakistan, Bangladesh, China, Philippines, Indonesia), while only 5-10% of the US population test positive.
Year: 2008
Every person with untreated active TB will infect on average 10-15 people each year.
A new infection occurs every second.
WHO estimated that one-third of the global population was infected with TB bacteria.
8.8 million new cases of TB developed. The proportion of people who become sick with tuberculosis each year is stable or falling worldwide but, because of population growth, the absolute number of new cases is still increasing.
