About Tuberculosis
What is tuberculosis?
How is tuberculosis contracted?
What are the symptoms of tuberculosis?
What is tuberculosis?
Tuberculosis (TB) is an infectious disease caused by a germ (bacterium). The germ is called Mycobacterium tuberculosis. This germ often affects the lungs. It may involve any organ and may infect anyone at any age.
In the United States, the number of TB cases steadily decreased until 1986. Then an increase was noted. Since 1992, TB has been declining. In 2005, the case rate was 4.8 per 100,000 population. This is about 14,100 new cases of active disease each year. TB cases are primarily related to HIV/AIDS, homelessness, drug abuse and foreign-born persons.
How is tuberculosis contracted?
TB is a contagious or infectious disease. It is spread from person-to-person. A person is often infected by inhaling the germs. These germs have been sprayed into the air by someone with the active disease who coughs.
However, inhaling the germ does not mean you will develop active disease. A person's natural body defenses are often able to control the infection so that it does not cause disease. In this case, the person would be infected, but does not have active disease. Only about 10% of those infected will develop TB in their lifetimes.
Active disease can occur in an infected person when the body's resistance is low or if there is a large or prolonged exposure to the germs that overcome the body's natural defenses. The body's response to active TB infection produces inflammation that can damage the lungs. The amount of damage may be quite extensive even though the symptoms may be minimal.
What are the symptoms of tuberculosis?
The usual symptoms of TB disease include:
- Fever
- Night sweats
- Cough
- Loss of appetite
- Weight loss
- Blood in the sputum (phlegm)
- Loss of energy
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This information has been approved by Gwen Huitt M.D. (April 2006).
