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All about tuberculosis tuberculosis transmission causes of tuberculosis risk factors for tuberculosis symptoms of tuberculosis diagnosis of tuberculosis treatment for tuberculosis prevention of tuberculosis

How is tuberculosis transmitted?

Tuberculosis is spread through air droplets which are expelled when persons with infectious TB disease cough, sneeze, speak, or sing. Close contacts (persons with prolonged, frequent, or intense contact) are at highest risk of becoming infected (22 percent infection rate). Others at risk include foreign-born from areas where TB is common, residents and

employees of high-risk congregate settings, health care workers who serve high-risk clients, medically underserved, low-income populations, high-risk racial or ethnic minority populations, children exposed to adults in high-risk categories, and persons who inject illicit drugs.

The tuberculosis germ is carried on droplets in the air, and can enter the body through the airway. A person with active pulmonary tuberculosis can spread the disease by coughing or sneezing. The process of catching tuberculosis involves two stages: first, a person has to become infected; second, the infection has to progress to disease. To become infected, a person has to come in close contact with another person having active tuberculosis. In other words, the person has to breathe the same air in which the person with active disease coughs or sneezes.

Transmission occurs only from persons with active TB disease (not latent TB infection). A person has to come in contact with someone who has active TB disease with TB germs present in the sputum. The likelihood of this happening also depends on the time spent in close contact with the person with active disease. The process of infection progresses to disease in about ten percent of those infected, and it can happen any time during the remainder of their lives. Although the chance of progression to disease diminishes with the passage of time, tuberculosis can develop more easily if the immune system weakens, as happens with malnutrition, AIDS, diabetes, cancer, or treatment with immunosuppressant drugs. In people with both HIV and TB infection, as many as eight percent can develop TB each year. In the United States, about one person in every 5,500 is diagnosed as infected with tuberculosis.

More information on tuberculosis

What is tuberculosis? - Tuberculosis (TB) is a contagious, wasting disease characterized by the coughing up of mucus and sputum, fever, weight loss, and chest pain.
How is tuberculosis transmitted? - Tuberculosis is spread through air droplets which are expelled when persons with infectious TB disease cough, sneeze, speak, or sing.
What causes tuberculosis? - Tuberculosis is caused by the bacterium Mycobacterium tuberculosis. Transmission occurs only from persons with active TB disease.
What're the risk factors for tuberculosis? - Tuberculosis is more common in elderly persons. The risk of tuberculosis increases when the immune system is unhealthy.
What are the symptoms of tuberculosis? - Symptoms of tuberculosis include cough, sputum, bleeding from the lungs, fever, night sweats, loss of weight, and weakness.
How is tuberculosis diagnosed? - Diagnosis of tuberculosis includes a medical history, a physical examination, a tuberculin skin test, a chest X-ray, and microbiologic smears and cultures.
What's the treatment for tuberculosis? - Directly observed treatment is effective in eliminating the problem of noncompliance. Surgical treatment of tuberculosis may be used if medications are ineffective.
How to prevent tuberculosis? - Preventive measures for tuberculosis include strict standards for ventilation, air filtration, and isolation methods. Preventive antibiotic treatment may have to be given.
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All information is intended for reference only. Please consult your physician for accurate medical advices and treatment. Copyright 2005,, all rights reserved. Last update: July 18, 2005