Nov 20, 2008
Tuberculosis (TB) is an infectious disease of the lungs caused by the bacterium Mycobacterium tuberculosis. In the mid-nineteenth century, about one-fourth of the mortality rate was attributable to tuberculosis. It was particularly rampant in early childhood and young adulthood. Its presence was felt throughout the world, but by the 1940s, with the introduction of antibiotics, there was a sharp decline of cases in developed countries. For less-developed countries with poor public health structures, tuberculosis is still a major problem. Since 1989, however, there has been an increase in reported cases in economically advanced countries due mainly to immunosuppression associated with AIDS, and the emergence of antibiotic-resistant strains of TB.
The bacillus infects the lungs of those who inhale the infected droplets formed during coughing by an individual who has an active case of the disease. It can also be transmitted by unpasteurized milk, as animals can be infected with the bacteria. The disease is dormant in different parts of the body until it becomes active and attacks the lungs, leading to a chronic infection. Symptoms include fatigue, loss of weight, night fevers and chills, and persistent coughing with sputumstreaked blood. The virulent form of the infection can then spread to other parts of the body. Without treatment, the condition is eventually fatal.
Chest x rays and sputum examinations can show the presence of tuberculosis. Tuberculin, a purified protein taken from the tuberculosis bacilli, is placed under the skin of the forearm during a tuberculosis skin test. In two or three days if there is a red swelling at the site, the test is positive, and indicates TB infection, but not necessarily active TB disease. Early detection of the disease facilitates effective treatment to avoid the possibility of it becoming active later on.
Populations at risk of contracting TB are people with certain medical conditions or those using drugs for medical conditions that weaken the immune system. Others at risk are low-income groups, people from undeveloped countries with high TB rates, people who work in or are residents of long-term care facilities (nursing homes, prisons, hospitals), those who are significantly underweight, alcoholics, and intravenous drug users.
Traces of lesions from tuberculosis have been found in the lungs of ancient Egyptian mummies. The recent discovery of a Pre-Columbian mummy has resolved the debate on whether or not European explorers introduced the disease to the New World. Lung samples from a Peruvian woman who lived 500 years before Columbus discovered America show a lump that was identified as tuberculosis by DNA testing. Hippocrates, a Greek physician who lived from 460 to 370 B.C., described the disease. The Greek name for the disease was phthisis, derived from the verb phthinein, meaning to waste away. Tuberculosis was also called consumption because of the wasting away effects (notably, significant losses of weight over a period of time) of the disease.
In 1839, Johann Schonlein is credited with first labeling the disease tuberculosis. In 1882, the tubercle bacillus was discovered by Robert Koch, the German physician who pioneered the science of bacteriology. This landmark discovery was followed eight years later by his extraction of a protein from dead bacilli called tuberculin. This protein is still used to test for the presence of TB infection in a dormant or early stage. Another important diagnostic breakthrough came in 1895 with the discovery of Wilhelm Conrad Roentgen's x rays. The presence of TB lesions was detected on x rays.
Two twentieth century French scientists, Albert Calmette and Camille Guerin, developed a vaccine against tuberculosis from a weakened strain of bovine bacillus. Called BCG for Bacillus-Calmette-Guerin, this vaccine is the only one still in use although some scientists question its effectiveness. Despite doubts about the vaccine, it is still widely used, especially in TB endemic countries where other preventive measures are lacking. The U.S. Public Health Service's policy recommends testing and drug therapy for those infected instead of vaccination. The two factors responsible for this policy are the low incidence of TB in the United States and the doubts raised about BCG. The Centers for Disease Control and Prevention, (CDC), however, in its concern over the rising incidence of TB in the United States and the appearance of multidrug-resistant tuberculosis (MDR TB) which is difficult to treat, reexamined the TB vaccination issue, and released recommendations for its use in limited situations.
The CDC still recommends the use of skin tests and drug therapy as the most important measures in controlling the incidence of TB in the United States. Drug therapy is 90% effective in halting the infection. Since those vaccinated test positive with the skin test, a vaccination program would interfere with skin testing. Mass vaccination would risk giving up a simple test that provides an early warning. Relying on the drug treatment program to stop TB epidemics, however, has one major drawback. The drug therapy takes six months to a year before halting the infection. People infected are often among the homeless, poor, drug addicted, or criminal societies. Unless these people are carefully supervised to make sure they complete a regimen of drug therapy, it is difficult to effect a cure for the disease.
Throughout the nineteenth century and up until the 1960s, physicians sent their TB patients to sanatoriums which were rest homes located in mountains or semi-arid regions such as the American southwest. These locations were supposed to help the breathing process by providing clean and dry air. Physicians assumed that deeper, easier breathing in a work-free environment would help overcome the disease. Prior to the advent of antibiotics, these retreats were the only recourse for chronically ill tubercular patients. Although treatment in sanatoriums did help many, they were phased out before the 1960s, and replaced by antibiotic drug chemotherapy, which could be administered in either a hospital or home environment. Over 90% of TB patients can be cured by a combination of inexpensive antibiotics, but it is necessary they be used for a period of at least six months.
The impact of tuberculosis was evident in the nineteenth and early twentieth centuries in literature, art, and music. Puccini's opera, La Boheme, was created around the tragic death of the tubercular heroine, Mimi. Since TB often attacked the young, many poets, artists and musicians fell prey to the disease before they had a chance to fulfill their creative work. Among them, Amedeo Modigliani, John Keats, Frederic Chopin, and Anton Chekhov were claimed by the disease, along with millions of other young people during the period. In the United States, American playwright Eugene O'Neill was one of the fortunate few who did recover in a sanatorium and went on to write his plays. His early play, The Straw, written in 1919, dramatically shows what life was like in a sanatorium.
In the past, U.S. city and state governments were actively involved in regulations that controlled infected people from spreading the infection. At present, federal, state, and local agencies must again take a leading role in formulating a public policy on this complicated health problem. Several states are using a program called Directly Observed Therapy (DOT) to combat the rising incidence of TB. This program has met with considerable success in lowering reported cases of TB as much as 15% in New York City during the late 1990s.
DOT is offered at soup kitchens, clinics, hospitals, neighborhood health centers, and drug rehabilitation centers. Outreach workers enable those with TB to get help with the least amount of red tape. The wide array of medicines needed to treat the disease are made available, and ample funding has been provided from federal, state, and local agencies. Apartments are located for homeless patients and special provisions are made to help released prison inmates and those on parole. Guidelines for compassionate, supervised medical services are periodically reviewed for the successful implementation of the DOT program.
Despite such measures, the U.S. Department of Health and Human Services predicts tuberculosis, will spread further by the year 2005. In 1990, there were 7,537,000 TB cases worldwide. That number is expected to rise to 11,875,000 in 2005, a 58% increase. Most of the rise in rate is attributed to demographic factors (77%) while 23% accounts for the epidemiological factors, i.e., the rise in HIV infection. Approximately 30 million people around the world will die of TB from 2000 to 2009. These predictions are considered conservative because many cases of TB are never reported.
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