How Does TB Spread?

TB is spread when tiny airborne droplets containing the organism are inhaled. An infected person expels the droplets by coughing, sneezing, talking or singing. These droplets can remain airborne and dangerous for hours after the cough or sneeze. A healthy person inhales the droplets and the bacteria may reproduce in the lungs and spread throughout the body by way of the blood stream. A healthy person's immune system normally contains the infection often for a lifetime.

Only about one in ten infected persons will develop active TB. This usually happens when a person's immune system is weakened by some other chronic disease or outside intervention. They may eventually become active TB cases, but most people feel well and don't pose a hazard to anyone else.

Most people who are casually exposed to people with active TB are not likely to get the disease. If you have close contact for a long period of time with a person who has active TB, you are at risk. TB patients with the active disease are no longer infectious after they begin treatment. Their own treatment will progress for months, but they can't spread the disease to others.

Although the tuberculosis bacillus was identified in 1882, it has only been in the recent past that advances in treatment and prevention have been made. The future promises even more dramatic changes.

Symptoms

The signs and symptoms of TB may include cough, fatigue, weight loss, swollen lymph nodes, night sweats and fever. Tuberculin skin testing can be used to identify carriers of the disease as well as people who have the active disease. Another TB test is known as the Purified Protein Derivative (PPD) test. A small quanity of tuberculin is injected between the layers of skin. The test is evaluated 48 to 72 hours later. A person suspected of having TB involving the lungs or who tests positive for TB by a skin test, would also have a chest x-ray. Depending upon other possible locations of the disease, a variety of other specimens might be tested.

Treatment

Unlike most infections, which can be cleared up relatively quickly, TB is stubborn. Active tuberculosis takes months to cure. Combinations of three drugs is commonly used-Isoniazid, rifampin, and pyrazinamide. Uncomplicated TB may require six to nine months of medication. In some cases, a four drug combination is used including the first three and either ethambutol or streptomycin. The important thing for patients to remember is to take all of the medication prescribed for the entire time period that it is ordered.

Drug resistant strains of TB have cropped up in isolated pockets around the country. This is worrisome because it means that a strain of super germs is loose, which has developed the ability to withstand the attack of commonly-used drugs listed above. Treatment in these cases is more difficult, more expensive, and may not be successful.