Tuberculosis

March 2012

Key facts

  • Tuberculosis (TB) is an infectious disease that spreads through the air.
  • When infectious people cough, sneeze, talk or spit, they propel TB germs (bacilli), into the air.
  • Only people who are sick with TB in their lungs (pulmonary TB) are infectious.
  • One-third of the world's population is currently infected with the TB bacillus, but only 5-10% of people infected will become sick with the disease.
  • The immune system "walls off" the TB bacilli which, protected by a thick waxy coat, can lie dormant in the body for years.
  • People with HIV are much more likely to develop TB after infection due to their weakened immune systems.
  • Left untreated, each person with active TB disease will infect on average between 10 and 15 people every year.

The tuberculosis epidemic

  • Tuberculosis mostly affects young adults in their most productive years.
  • 95% of TB deaths are in the developing world.
  • WHO estimates that the largest number of new TB cases in 2010 occurred in Asia, which accounted for 59% of incident cases globally.
  • India alone accounted for an estimated one quarter (26%) of all TB cases worldwide, and China and India combined accounted for 38%.
  • Estimated TB incidence rates are highest in sub-Saharan Africa with over 350 cases per 100 000 population.
  • The number of people who fell ill with TB dropped to 8.8 million in 2010, including 1.1 million cases among people with HIV.
  • An estimated 1.4 million people died from TB in 2010, including 320,000 deaths among women and 350,000 people with HIV. This is equal to 3,800 deaths a day.
  • The absolute number of incident cases has been falling very slowly since 2006, when the decline in the incidence rate (per 100,000) started to exceed the rate of growth in the world's population.
  • In 2010, there was an estimated prevalence of 650,000 cases of multidrug-resistant TB (MDR-TB), and in 2008 it was estimated there were 150,000 MDR-TB deaths annually.
  • While more people were being treated for MDR-TB in 2010, the number represents only 16% of the estimated number of MDR-TB patients.
  • 46% of HIV-positive TB patients were enrolled on antiretrovirals and 77% started on co-trimoxazole preventive treatment in 2010.
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