What is tuberculosis?
Tuberculosis (TB) is a life-threatening infection that primarily affects your lungs. Every year, tuberculosis kills nearly 2 million people worldwide. The infection is common — about one-third of the human population is infected with TB, with one new infection occurring every second.
Tuberculosis has plagued human beings for millennia. Signs of tubercular damage have been found in Egyptian mummies and in bones dating back at least 5,000 years. Today, despite advances in treatment, TB is a global pandemic, fueled by the spread of HIV/AIDS, poverty, a lack of health services and the emergence of drug-resistant strains of the bacterium that causes the disease.
Tuberculosis spreads through airborne droplets when a person with the infection coughs, talks or sneezes. In general, you need prolonged exposure to an infected person before becoming infected yourself.
Tuberculosis is caused by Mycobacterium
tuberculosis.
M. tuberculosis is:
Gram-positive
Rod-shaped
Pleiomorphic
Pathogenic
Non-motile
Acid-fast
Hydrophobic
What are the main causes of tuberculosis?
You can catch TB by breathing droplets in the air that contain the bacterium M. tuberculosis. These are spread through the air when someone with TB coughs or sneezes. TB is only infectious when it affects the lungs (See Symptoms). Although it’s spread through the air, you need to be closely exposed to a person with TB for some time before you catch it. People most commonly catch TB from people they live or work with.
You are more likely to get TB if you:
already have a weakened immune system (eg from HIV/AIDS or from taking medicines that suppress your immune system)
have diabetes
regularly come into contact with people who have TB lung infection
are young or elderly
are malnourished
smoke or drink alcohol excessively
live in overcrowded housing
travel to, or come from, places where TB is common
Some other causes of tuberculosis are :
• AIDS
• Immunodeficiency
• Pneumoconiosis- in coal mine workers
• Malnutrition
• Alcoholism
In the United States and other developed countries, tuberculosis is more likely to affect older people. In poorer countries, it is a disease of young adults. People of European ancestry are somewhat less likely to get tuberculosis because the bacterium for it has existed a long time in Europe. People from other parts of the world, where tuberculosis is a newer disease, are at greater risk of developing it. In the United States, tuberculosis is more common among African Americans, Native Americans and immigrants from non-European countries.
Poverty, poor nutrition, crowded living conditions, exposure to tuberculosis and lack of access to medical care all increase the risk of developing tuberculosis.
A person can also become infected with tuberculosis bacteria when he or she inhales minute particles of infected sputum from the air. The bacteria get into the air when someone who has a tuberculosis lung infection coughs, sneezes, shouts, or spits (which is common in some cultures). People who are nearby can then possibly breathe the bacteria into their lungs. You don’t get TB by just touching the clothes or shaking the hands of someone who is infected.