Tuberculosis
Tuberculosis (TB), chronic or acute bacterial infection that primarily attacks the lungs, but which may also affect the kidneys, bones, lymph nodes, and brain. The disease is caused by Mycobacterium tuberculosis, a rod-shaped bacterium. Symptoms of TB include coughing, chest pain, shortness of breath, loss of appetite, weight loss, fever, chills, and fatigue. Children and people with weakened immune systems are the most susceptible to TB. Half of all untreated TB cases are fatal.
TB is transmitted from person to person, usually by inhaling bacteria-carrying air droplets. When a person sick with TB coughs, sneezes, or speaks, small particles that carry two to three bacteria surrounded by a layer of moisture are released in the air. When another person inhales these particles, the bacteria may lodge in that person’s lungs and multiply.
Diagnosis of TB requires two separate methods. Tuberculin skin testing is a method of screening for exposure to TB infection. A person who was infected with TB will have developed a hypersensitivity to the TB bacteria even if they did not develop the disease. A purified protein derived from the bacteria is injected into the skin. The skin area is inspected 48 to 72 hours later for a bump. A positive test implies that TB infection has occurred. Skin tests are not 100 percent accurate and they do not always indicate the presence of active disease.
General preventive measures can be taken to reduce the spread of TB in public places. Ventilation systems lessen the chance of infection by dispersing the bacteria. Ultraviolet lighting also reduces, but does not eliminate, the threat of infection by killing TB bacteria in confined spaces. Vaccines, such as the bacillus Calmette Guerin (BCG) vaccine, prepared from bacteria that have been weakened, are another preventive measure. The BCG vaccine is most effective in preventing childhood cases of TB.
With the advent of effective antibiotics for TB, drug therapy has become the cornerstone of treatment. Single-drug treatment often causes bacterial resistance to drugs. Therefore, all recommended therapies include multiple drugs given for at least 6 months, often for as long as 9 to 12 months. Adjustments to the treatments are made based on susceptibility of the bacterial strain. A combination of antibiotics, including isoniazid, rifampin, streptomycin, pyrazinamide, and ethambutol, is usually prescribed.
TB is transmitted from person to person, usually by inhaling bacteria-carrying air droplets. When a person sick with TB coughs, sneezes, or speaks, small particles that carry two to three bacteria surrounded by a layer of moisture are released in the air. When another person inhales these particles, the bacteria may lodge in that person’s lungs and multiply.
Diagnosis of TB requires two separate methods. Tuberculin skin testing is a method of screening for exposure to TB infection. A person who was infected with TB will have developed a hypersensitivity to the TB bacteria even if they did not develop the disease. A purified protein derived from the bacteria is injected into the skin. The skin area is inspected 48 to 72 hours later for a bump. A positive test implies that TB infection has occurred. Skin tests are not 100 percent accurate and they do not always indicate the presence of active disease.
General preventive measures can be taken to reduce the spread of TB in public places. Ventilation systems lessen the chance of infection by dispersing the bacteria. Ultraviolet lighting also reduces, but does not eliminate, the threat of infection by killing TB bacteria in confined spaces. Vaccines, such as the bacillus Calmette Guerin (BCG) vaccine, prepared from bacteria that have been weakened, are another preventive measure. The BCG vaccine is most effective in preventing childhood cases of TB.
With the advent of effective antibiotics for TB, drug therapy has become the cornerstone of treatment. Single-drug treatment often causes bacterial resistance to drugs. Therefore, all recommended therapies include multiple drugs given for at least 6 months, often for as long as 9 to 12 months. Adjustments to the treatments are made based on susceptibility of the bacterial strain. A combination of antibiotics, including isoniazid, rifampin, streptomycin, pyrazinamide, and ethambutol, is usually prescribed.