What is tuberculosis?
Tuberculosis, or TB, is a contagious disease caused by a bacterium called Mycobacterium tuberculosis (MTB). It usually destroys the lungs, but can also affect any other organ in the body. Common symptoms include coughing, loss of weight, fever and night sweats, tiredness and loss of appetite. A vaccine for TB has been in use since the 1920s, but it is only of limited effectiveness.
How many people are affected?
The statistics are shocking:
- More than two billion people, one third of the world’s population, are infected with the bacteria that can lead to TB.
- A new person is infected with the bacteria every second.
- Between 5% and 10% of people infected with the bacteria will become sick with TB or infectious during their lifetime.
- People living with HIV are much more likely to develop TB because of their weakened immune systems.
- In 2006 there were 9.2 million new cases of TB – 55% were in Asia, and 31% in Africa.
- Despite the rate of new cases levelling off, 1.7 million people died from TB in 2006.
- TB is a leading killer of adult women under 45.
How is it spread?
Like the common cold, TB is spread through the air. A person only needs to inhale a small number of bacteria to become infected.
Infection with the bacteria doesn’t mean a person will become sick with TB, and the bacteria can lie dormant for years. Most people become sick with TB if their immune systems are weak – this could be due to poor nutrition, or other poor health – particularly HIV.
When someone who is ill with TB coughs, sneezes, talks or spits they propel TB bacteria into the air. People who are ill with TB and don’t receive treatment infect on average between 10 and 15 more people each year.
Who is most at risk?
Poverty and TB are closely linked. As an airborne disease TB can affect anyone, anywhere. But people with weak immune systems are most susceptible. It is much more prevalent in poor communities where people often live in crowded, unventilated housing, with little access to health services.
Young children are at particular risk, especially if they are malnourished, or have other infections or worms. Cases in children are often missed because adult infections are more common. People living with HIV are also particularly at risk, and TB is harder to diagnose in HIV-positive people.
How does TB affect women?
TB is the single biggest killer of young women today. Often marginalised or disadvantaged, women may avoid visiting a health clinic out of fear that their family will reject them if they are diagnosed, or because they simply don’t have the money or free time to seek help. Slow to get treatment, women may be seriously ill when they finally do see a health worker.
The stigma of having TB can also dash any hope for a single woman to get married, while married women with TB are sometimes abandoned by their husbands.