Tuberculosis

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Definition

Tuberculosis (TB) is a potentially fatal contagious disease that can affect almost any part of the body but is mainly an infection of the lungs. It is caused by a bacterial microorganism, the tubercle bacillus or Mycobacterium tuberculosis. Although TB can be treated, cured, and can be prevented if persons at risk take certain drugs, scientists have never come close to wiping it out. Few diseases have caused so much distressing illness for centuries and claimed so many lives.

Description

Tuberculosis was popularly known as consumption for a long time. Scientists know it as an infection caused by M. tuberculosis. In 1882, the microbiologist Robert Koch discovered the tubercle bacillus, at a time when one of every seven deaths in Europe was caused by TB. Because antibiotics were unknown, the only means of controlling the spread of infection was to isolate patients in private sanitoria or hospitals limited to patients with TB—a practice that continues to this day in many countries. The net effect of this pattern of treatment was to separate the study of tuberculosis from mainstream medicine. Entire organizations were set up to study not only the disease as it affected individual patients, but its impact on the society as a whole. At the turn of the twentieth century more than 80% of the population in the United States were infected before age 20, and tuberculosis was the single most common cause of death. By 1938 there were more than 700 TB hospitals in this country.

Tuberculosis spread much more widely in Europe when the industrial revolution began in the late nineteenth century. The disease became widespread somewhat later in the United States, because the movement of the population to large cities made overcrowded housing so common. When streptomycin, the first antibiotic effective against M. tuberculosis, was discovered in the early 1940s, the infection began to come under control. Although other more effective anti-tuberculosis drugs were developed in the following decades, the number of cases of TB in the United States began to rise again in the mid-1980s. This upsurge was in part again a result of overcrowding and unsanitary conditions in the poor areas of large cities, prisons, and homeless shelters. Infected visitors and immigrants to the United States also contributed to the resurgence of TB. An additional factor is the AIDS epidemic. AIDS patients are much more likely to develop tuberculosis because of their weakened immune systems. There still are an estimated 8 to 10 million new cases of TB each year worldwide, causing roughly 3 million deaths.

THE ELDERLY. Tuberculosis is more common in elderly persons. More than one-fourth of the nearly 23,000 cases of TB reported in the United States in 1995 developed in people above age 65. Many elderly patients developed the infection some years ago when the disease was more widespread. There are additional reasons for the vulnerability of older people: those living in nursing homes and similar facilities are in close contact with others who may be infected. The aging process itself may weaken the body's immune system, which is then less able to ward off the tubercle bacillus. Finally, bacteria that have lain dormant for some time in elderly persons may be reactivated and cause illness.

RACIAL AND ETHNIC GROUPS. TB also is more common in blacks, who are more likely to live under conditions that promote infection. As the end of the century approaches, two-thirds of all cases of TB in the United States affect African Americans, Hispanics, Asians, and persons from the Pacific Islands. Another one-fourth of cases affect persons born outside the United States. As of 1992, the risk of TB was still increasing in all these groups.

LIFESTYLE FACTORS. The high risk of TB in AIDS patients extends to those infected by human immunodeficiency virus (HIV) who have not yet developed clinical signs of AIDS. Alcoholics and intravenous drug abusers are also at increased risk of contracting tuberculosis. Until the economic and social factors that influence the spread of tubercular infection are remedied, there is no real possibility of completely eliminating the disease.

— David A. Cramer, MD

Dictionary: tu·ber·cu·lo·sis  (tʊ-bûr'kyə-lō'sĭs, tyʊ-)

1. An infectious disease of humans and animals caused by the tubercle bacillus and characterized by the formation of tubercles on the lungs and other tissues of the body, often developing long after the initial infection.
2. Tuberculosis of the lungs, characterized by the coughing up of mucus and sputum, fever, weight loss, and chest pain.

[Latin tūberculum, tubercle; see tubercle + –OSIS.]

An infectious disease caused by the bacillus Mycobacterium tuberculosis. It is primarily an infection of the lungs, but any organ system is susceptible, so its manifestations may be varied. Effective therapy and methods of control and prevention of tuberculosis have been developed, but the disease remains a major cause of mortality and morbidity throughout the world. The treatment of tuberculosis has been complicated by the emergence of drug-resistant organisms, including multiple-drug-resistant tuberculosis, especially in those with HIV infection. See also Acquired immune deficiency syndrome (AIDS).

Mycobacterium tuberculosis is transmitted by airborne droplet nuclei produced when an individual with active disease coughs, speaks, or sneezes. When inhaled, the droplet nuclei reach the alveoli of the lung. In susceptible individuals the organisms may then multiply and spread through lymphatics to the lymph nodes, and through the bloodstream to other sites such as the lung apices, bone marrow, kidneys, and meninges.

The development of acquired immunity in 2 to 10 weeks results in a halt to bacterial multiplication. Lesions heal and the individual remains asymptomatic. Such an individual is said to have tuberculous infection without disease, and will show a positive tuberculin test. The risk of developing active disease with clinical symptoms and positive cultures for the tubercle bacillus diminishes with time and may never occur, but is a lifelong risk. Only 5% of individuals with tuberculous infection progress to active disease. Progression occurs mainly in the first 2 years after infection; household contacts and the newly infected are thus at risk.

Many of the symptoms of tuberculosis, whether pulmonary disease or extrapulmonary disease, are nonspecific. Fatigue or tiredness, weight loss, fever, and loss of appetite may be present for months. A fever of unknown origin may be the sole indication of tuberculosis, or an individual may have an acute influenzalike illness. Erythema nodosum, a skin lesion, is occasionally associated with the disease.

The lung is the most common location for a focus of infection to flare into active disease with the acceleration of the growth of organisms. There may be complaints of cough, which can produce sputum containing mucus, pus- and, rarely, blood. Listening to the lungs may disclose rales or crackles and signs of pleural effusion (the escape of fluid into the lungs) or consolidation if present. In many, especially those with small infiltration, the physical examination of the chest reveals no abnormalities.

Miliary tuberculosis is a variant that results from the blood-borne dissemination of a great number of organisms resulting in the simultaneous seeding of many organ systems. The meninges, liver, bone marrow, spleen, and genitourinary system are usually involved. The term miliary refers to the lung lesions being the size of millet seeds (about 0.08 in. or 2 mm). These lung lesions are present bilaterally. Symptoms are variable.

Extrapulmonary tuberculosis is much less common than pulmonary disease. However, in individuals with AIDS, extrapulmonary tuberculosis predominates, particularly with lymph node involvement. Fluid in the lungs and lung lesions are other common manifestations of tuberculosis in AIDS. The lung is the portal of entry, and an extrapulmonary focus, seeded at the time of infection, breaks down with disease occurring.

Development of renal tuberculosis can result in symptoms of burning on urination, and blood and white cells in the urine; or the individual may be asymptomatic. The symptoms of tuberculous meningitis are nonspecific, with acute or chronic fever, headache, irritability, and malaise.

A tuberculous pleural effusion can occur without obvious lung involvement. Fever and chest pain upon breathing are common symptoms.

Bone and joint involvement results in pain and fever at the joint site. The most common complaint is a chronic arthritis usually localized to one joint. Osteomyelitis is also usually present.

Pericardial inflammation with fluid accumulation or constriction of the heart chambers secondary to pericardial scarring are two other forms of extrapulmonary disease.

The principal methods of diagnosis for pulmonary tuberculosis are the tuberculin skin test (an intracutaneous injection of purified protein derivative tuberculin is performed, and the injection site examined for reactivity), sputum smear and culture, and the chest x-ray. Culture and biopsy are important in making the diagnosis in extrapulmonary disease.

A combination of two or more drugs is used in the initial therapy of tuberculous disease. Drug combinations are used to lessen the chance of drug-resistant organisms surviving. The preferred treatment regimen for both pulmonary and extrapulmonary tuberculosis is a 6-month regimen of the antibiotics isoniazid, rifampin, and pyrazinamide given for 2 months, followed by isoniazid and rifampin for 4 months. Because of the problem of drug-resistant cases, ethambutol can be included in the initial regimen until the results of drug susceptibility studies are known. Once treatment is started, improvement occurs in almost all individuals. Any treatment failure or individual relapse is usually due to drug-resistant organisms. See also Drug resistance.

The community control of tuberculosis depends on the reporting of all new suspected cases so case contacts can be evaluated and treated appropriately as indicated. Individual compliance with medication is essential. Furthermore, measures to enhance compliance, such as directly observed therapy, may be necessary. See also Mycobacterial diseases.

Tuberculosis is caused by the microorganism Mycobacterium tuberculosis, or tubercle bacillus. It was in 1882 that Robert Koch, among his many historic contributions to bacteriology, identified this as the cause of the disease, thus firmly establishing for the first time its infective nature. It has been estimated that one-third of the world's population has been infected by M. tuberculosis but only a minority, probably about 10%, go on to develop disease. Disease manifests in any number of ways, almost all of them chronic, involving practically any part of the body. The most common site involved is the lungs, where cavities are produced. When this occurs patients have a cough with sputum (which sometimes contains blood), weight loss, and fever. Those with this type of disease are the most infectious, because of the presence of the bacillus in the sputum. Animals also carry the disease; although Koch had denied the possibility, it was later realized that the bovine strain of the organism, Mycobacterium bovis, could cause human infection from cow's milk.

Historically, tuberculosis has long ranked among the most feared of diseases. Such dread is reflected in some of its alternative names, including John Bunyan's ‘Captain of all these Men of Death’, and Charles Dickens' ‘dread disease’ which capture something of the prevalence of the disease in their times. Other names conjure up images of the disease process: the term ‘consumption’ describes what happened to an individual — a progressive emaciation and wasting away. Still other terms, such ‘the King's Evil’ describe the lottery of survival (cure arising from the king's touch in medieval England). Yet tuberculosis is not only a disease of the past. Keats' ‘death warrant’ continues to haunt us. Historically tuberculosis conjures up romantic images of pale, wraith-like artists suffering lingering deaths. Literature, art, and music have all recorded and been transformed by the disease. Those who have succumbed to the disease form a veritable who's who of the artistic and political worlds and notions persist that those with artistic leanings are at greater risk from tuberculosis. As Susan Sontag noted in Illness as Metaphor, ‘tuberculosis was thought to come from too much passion, afflicting the reckless and sensual.’ Gradually, however, perceptions changed. In the US, for example, Katherine Ott noted in Fevered Lives that this ‘most flattering of all diseases’ of the 1870s was transformed, as awareness of the social associations grew in the 1880s, into a disease which was seen as the consequence of either acquired or inherited degeneracy and later came to mirror ethnic and racial fears and prejudices. Yet by the turn of the century the enthusiasm for pointing the finger at individual weaknesses was tempered by an increasing awareness that society's strictures were in part responsible. In truth, in past centuries tuberculosis was a frequent killer of people from all walks of life, not only the famous and infamous, the artistic and notorious. Those living in poverty and squalor were always most susceptible.

The sanatorium movement, which promoted wholesome rest and genteel exercise in pleasant surroundings, took off in the second half of the nineteenth century. In Britain, which borrowed the idea from Germany, the first sanatoria opened in the 1890s. Although many sanatoria in Europe catered for a select, affluent, cosmopolitan clientele (an image which persists in the popular imagination conjured up by establishments such as those at Davos in Switzerland), sanatorium treatment also, by the 1920s, became available for those unable to pay, and the average duration of stay shortened. However a decline in the sanatorium movement started with the onset of World War I and was hastened by the Depression which followed. Although there were still thousands of tuberculosis sufferers receiving care in sanatoria by the mid 1940s, the availability of effective drug treatment meant that they soon became obsolete. Removal of infectious sufferers from the community had contributed to a decrease in incidence of the disease, but for the patients in sanatoria or specialized hospitals there was no specific cure. Recovery was sometimes assisted by causing collapse of an infected lung by the introduction of air into the chest (artificial pneumothorax) or by an operation that ‘caved-in’ the overlying ribs (thoracoplasty).

The advent of drug treatment followed the discovery, by Selman Waksman in the US in 1944, that streptomycin was effective, and other drugs shortly followed. When chemotherapy from then on resulted in cure for most tuberculosis sufferers, contemporary commentators told stories largely of hope, of medicine's conquest of nature, and reflected less on societal hindrances to medicine's application. An optimistic faith in the benefits of science shone through such that it seemed merely a matter of time before this ancient scourge would be eradicated. At the time this optimism seemed well-founded: mortality rates in England and Wales, which had been falling by about 1% annually since the 1860s, declined dramatically from the mid 1940s. Death rates for respiratory tuberculosis in England and Wales were about 125/100 000 at the turn of the century, and by the 1960s had fallen to below 10/100 000. Preceding the advent of chemotherapy there had been improvements in social conditions and better identification of those with active disease, along with advances in bacteriology and in X-ray diagnosis. From the 1920s there were attempts to control bovine infection, first by certifying tuberculin tested (TT) herds, and later by heat treatment to kill bacteria in milk. Although this pasteurization had been considered as early as 1913, Britain lagged behind much of Europe and the US by more than a quarter of a century in putting it into consistent effect. A further preventative measure was the introduction in the 1950s of the BCG (Bacille Calmette Guérin) vaccination programme.

Despite the remarkable success in controlling tuberculosis in the West, the overriding optimism which followed the development of effective antituberculosis drugs in the 1940s and 1950s was somewhat premature. The disease continues to target those most marginalized and vulnerable. Each year more than 8 million people acquire tuberculosis (most of them in the developing world), and about 3 million die, including about 100 000 children, annually. In England and Wales there was concern as to why this should be, why Keats' death warrant should still be received by so many, given that we have had at our disposal for over fifty years drugs which are effective in curing the disease? The answer was known half a century ago.

‘Tuberculosis is a social disease, and presents problems that transcend the conventional medical approach. On the one hand, its understanding demands that the impact of social and economic factors on the individual be considered as much as the mechanisms by which tubercle bacilli cause damage to the human body. On the other hand, the disease modifies in a peculiar manner the emotional and intellectual climate of the societies that it attacks.’ Rene Dubos who, with his wife Jean, wrote these words in 1952, was one of the giants of twentieth-century medicine. As well as being a major figure in the development of antibacterial drugs in the US in the 1920s and 1930s, which led to the later successful antituberculous drugs, he was able, unlike so many, to see the place of tuberculosis in society and to recognize the limits of modern medicine. His words resonate through the years and perhaps are more pertinent now than ever. In 1993 the World Health Organization officially called the global threat of tuberculosis an ‘emergency’. New drug-resistant strains of the organism are spreading and modern medical approaches are failing to cure patients. In England and Wales there was a 20% increase in incidence of the disease between 1987 and 1990, weighted towards the underprivileged. Overcrowding, poverty, social alienation, increased incarceration rates in prisons, homelessness, and AIDS (the ‘deadly alliance’) are combining to overwhelm uncoordinated and under-resourced public health responses.

Perhaps nowhere have the consequences of contemporary public health failures been more obvious than in New York City. In the late 1980s and early 1990s an epidemic of this ancient disease killed hundreds of people, forcing politicians to rethink their approaches to those living on the margins of society, and provoking a response which has cost millions of dollars. As Rene Dubos knew all along, tuberculosis is as much a social and political disease as it is a medical condition.

— Richard Coker

Bibliography

• Coker, R. (2000). From chaos to coercion: detention and the control of tuberculosis. St Martins Press, New York.
• Dormandy, T. (1999). The White Death: a history of tuberculosis. The Hambledon Press, London.
• Ott, K. (1996). Fevered lives: tuberculosis in American culture since 1870. Harvard University Press, Cambridge MA.
• Ryan, F. (1992). Tuberculosis: the greatest story never told. Swift publishers, Bromsgrove, Worcestershire.
• Sontag, S. (1978). Illness as metaphor. Farrar, Straus and Giroux, New York

See also infectious diseases; immunization.

noun

An infectious disease producing lesions especially of the lungs: consumption (no longer in scientific use), phthisic (no longer in scientific use), phthisis (no longer in scientific use), white plague. See health/sickness.

An infectious disease caused by Mycobacterium tuberculosis and characterized by the formation of tubercles in the tissues.

Tuberculosis of tongue. (Regezi/Sciubba/Pogrel, 2000)

Definition

Tuberculosis (TB) is a contagious and potentially fatal disease that can affect almost any part of the body but manifests mainly as an infection of the lungs. It is caused by a bacterial microorganism, the tubercle bacillus or Mycobacterium tuberculosis. TB infection can either be acute and short-lived or chronic and long-term.

Description

Although TB can be prevented, treated, and cured with proper treatment and medications, scientists have never been able to eliminate it entirely. The organism that causes tuberculosis, popularly known as consumption, was discovered in 1882. Because antibiotics were unknown, the only means of controlling the spread of infection was to isolate patients in private sanatoria or hospitals limited to patients with TB—a practice that continues to this day in many countries. TB spread very quickly and was a leading cause of death in Europe. At the turn of the twentieth century more than 80% of the people in the United States were infected before age 20, and tuberculosis was the single most common cause of death. Streptomycin was developed in the early 1940s and was the first antibiotic effective against the disease. The number of cases declined until the mid- to late-1980s, when overcrowding, homelessness, immigration, decline in public health inspections, decline in funding, and the AIDS epidemic caused a slight resurgence of the disease. The increase in TB in the United States peaked in 1992, and new cases reported in the United States continue to decrease as of 2004. Yet the number of cases in foreign-born individuals is rising, and the number of deaths from TB has been rising, making TB a leading cause of death from infection throughout the world. It is estimated that in the next 10 years 90 million new cases of TB will be reported, with the result of 30 million deaths, or about 3 million deaths per year.

Several demographic groups are at a higher risk of contracting tuberculosis. Tuberculosis is more common in elderly persons. More than one-fourth of the nearly 23,000 cases of TB in the United States in 1995 were reported in people above age 65. TB also is more common in populations where people live under conditions that promote infection, such as homelessness and injection drug use. In the late 1990s, two-thirds of all cases of TB in the United States affected African Americans, Hispanics, Asians, and persons from the Pacific Islands. Finally, the high risk of TB includes people who have a depressed immune system. High-risk groups include alcoholics, people suffering from malnutrition, diabetics, and AIDS patients — and those infected by human immunodeficiency virus (HIV) — who have not yet developed clinical signs of AIDS. TB is the number one killer of women of childbearing age worldwide. In poor countries, women with TB often don't know they have the disease until symptoms become severe.

As of late 2002, TB is a major health problem in certain immigrant communities, such as the Vietnamese in southern California. One team of public health experts in North Carolina maintains that treatment for tuberculosis is the most pressing healthcare need of recent immigrants to the United States. In some cases, the vulnerability of immigrants to tuberculosis is increased by occupational exposure, as a recent outbreak of TB among Mexican poultry farm workers in Delaware indicates. Other public health experts are recommending tuberculosis screening at the primary care level for all new immigrants and refugees.

Causes & Symptoms

Transmission

Tuberculosis spreads by droplet infection, in which a person breathes in the bacilli released into the air when a TB patient exhales, coughs, or sneezes. However, TB is not considered highly contagious compared to other infectious diseases. Only about one in three people who have close contact with a TB patient, and fewer than 15% of more remote contacts, are likely to become infected. Unlike many other infections, TB is not passed on by contact with a patient's clothing, bed linens, or dishes and cooking utensils. Yet if a woman is pregnant, her fetus may contract TB through blood or by inhaling or swallowing the bacilli present in the amniotic fluid.

Once inhaled, water in the droplets evaporates and the tubercle bacilli may reach the small breathing sacs in the lungs (the alveoli), then spread through the lymph vessels to nearby lymph nodes. Sometimes the bacilli move through blood vessels to distant organs. At this point they may either remain alive but inactive (quiescent), or they may cause active disease. The likelihood of acquiring the disease increases with the concentration of bacilli in the air, and the seriousness of the disease is determined by the number of bacteria with which a patient is infected.

Ninety percent of patients who harbor M. tuberculosis do not develop symptoms or physical evidence of the disease, and their x rays remain negative. They are not contagious; however, these individuals may get sick at a later date and then pass on TB to others. Though it is impossible to predict whether a person's disease will become active, researchers surmise that more than 90% of cases of active tuberculosis come from this pool of people. An estimated 5% of infected persons get sick within 12-24 months of being infected. Another 5% heal initially but, after years or decades, develop active tuberculosis. This form of the disease is called reactivation TB, or post-primary disease. On rare occasions a previously infected person gets sick again after a second exposure to the tubercle bacillus.

Pulmonary Tuberculosis

Pulmonary tuberculosis is TB that affects the lungs, and represents about 85% of new cases diagnosed. It usually presents with a cough, which may or may not produce sputum. In time, more sputum is produced that is streaked with blood. The cough may be present for weeks or months and may be accompanied by chest pain and shortness of breath. Persons with pulmonary TB often run a low-grade fever and suffer from night-sweats. The patient often loses interest in food and may lose weight. If the infection allows air to escape from the lungs into the chest cavity (pneumothorax) or if fluid collects in the pleural space (pleural effusion), the patient may have difficulty breathing. The TB bacilli may travel from the lungs to lymph nodes in the sides and back of the neck. Infection in these areas can break through the skin and discharge pus.

Extrapulmonary Tuberculosis

Although the lungs are the major site of damage caused by tuberculosis, many other organs and tissues in the body may be affected. Abut 15% of newly diagnosed cases of TB are extrapulmonary, with a higher proportion of these being HIV-infected persons. The usual progression of the disease is to begin in the lungs and spread to locations outside the lungs (extrapulmonary sites). In some cases, however, the first sign of disease appears outside the lungs. The many tissues or organs that tuberculosis may affect include:

• Bones. TB is particularly likely to attack the spine and the ends of the long bones.
• Kidneys. Along with the bones, the kidneys are probably the most common site of extrapulmonary TB. There may, however, be few symptoms even though part of a kidney is destroyed.
• Female reproductive organs. The ovaries in women may be infected; TB can spread from them to the peritoneum, which is the membrane lining the abdominal cavity.
• Abdominal cavity. Tuberculous peritonitis may cause pain ranging from the mild discomfort of stomach cramps to intense pain that may mimic the symptoms of appendicitis.
• Joints. Tubercular infection of joints causes a form of arthritis that most often affects the hips and knees.
• Meninges. The meninges are tissues that cover the brain and the spinal cord. Infection of the meninges by the TB bacillus causes tuberculous meningitis, a condition that is most common in young children and the elderly. It is extremely dangerous. Patients develop headaches, become drowsy, and eventually comatose. Permanent brain damage can result without prompt treatment.
• Skin, intestines, adrenal glands, and blood vessels. All these parts of the body can be infected by M. tuberculosis. Infection of the wall of the body's main artery (the aorta), can cause it to rupture with catastrophic results. Tuberculous pericarditis occurs when the membrane surrounding the heart (the pericardium) is infected and fills up with fluid that interferes with the heart's ability to pump blood.
• Miliary tuberculosis. Miliary TB is a life-threatening condition that occurs when large numbers of tubercle bacilli spread throughout the body. Huge numbers of tiny tubercular lesions develop that cause marked weakness and weight loss, severe anemia, and gradual wasting of the body.

Diagnosis

TB is diagnosed through laboratory test results. The standard test for tuberculosis infection, the tuberculin skin test, detects the presence of infection, not of active TB. Skin testing has been done for more than 100 years. In this process, tuberculin is an extract prepared from cultures of M. tuberculosis. It contains substances belonging to the bacillus (antigens) to which an infected person has been sensitized. When tuberculin is injected into the skin of an infected person, the area around the injection becomes hard, swollen, and red within one to three days.

Today skin tests utilize a substance called purified protein derivative (PPD) that has a standard chemical composition and is therefore a good measure of the presence of tubercular infection. The PPD test, also called the Mantoux test, is not always 100% accurate; it can produce false positive as well as false negative results. The test may indicate that some people who have a skin reaction are not infected (false positive) and that some who do not react are in fact infected (false negative). The PPD test is, however, useful as a screener and can be used on people who have had a suspicious chest x ray, on those who have had close contact with a TB patient, and persons who come from a country where TB is common.

Because of the multiple and varied symptoms of TB, diagnosis on the basis of external symptoms is not always possible. TB is often discovered by an abnormal chest x ray or other test result rather than by a claim of physical discomfort by the patient. After an irregular x ray, a PPD test is always done to show whether the patient has been infected. To verify the test results, the physician obtains a sample of sputum or a tissue sample (biopsy) for culture. In cases where other areas of the body might be infected, such as the kidney or the brain, body fluids other than sputum (urine or spinal fluid, for example) can be used for culture.

One important new advance in the diagnosis of TB is the use of molecular techniques to speed the diagnostic process as well as improve its accuracy. As of late 2002, four molecular techniques are increasingly used in laboratories around the world. They include polymerase chain reaction to detect mycobacterial DNA in patient specimens; nucleic acid probes to identify mycobacteria in culture; restriction fragment length polymorphism analysis to compare different strains of TB for epidemiological studies; and genetic-based susceptibility testing to identify drug-resistant strains of mycobacteria.

Treatment

Because of the nature of tuberculosis, the disease should never be treated by alternative methods alone. Alternative treatments can help support healing, but treatment of TB must include drugs and will require the care of a physician. Any alternative treatments should be discussed with a medical practitioner before they are applied.

Supportive treatments include:

• Diet. Nutritionists recommend a whole food diet including raw foods, fluids, and particularly pears and pear products (pear juice, pear sauce), since pears may help heal the lungs. Other helpful foods include fenugreek, alfalfa sprouts, garlic, pomegranate, and yogurt or kefir. Four tablespoons of pureed steamed asparagus at breakfast and dinner taken for a few months may also be helpful.
• Nutritional therapy. Nutritionists may recommend one or many of the following vitamins and minerals: vitamin A at 300,000 IU for the first three days, 200,000 IU for the next two days, then 50,000 IU for several weeks; beta-carotene at 25,000-50,000 IU; vitamin E at up to 1,000 IU daily unless the patient is a premenopausal woman with premenstrual symptoms; lipotrophic formula (one daily); deglycerolized licorice; citrus seed extract; vitamin C; lung glandular; essential fatty acids; vitamin B complex; multiminerals; and zinc.
• Herb therapy may use the tinctures of echinacea, elecampane, and mullein taken three times per day, along with three garlic capsules three times per day.
• Hydrotherapy may be used up to five times weekly. Dr. Benedict Lust, the founder of naturopathy, supposedly cured himself of tuberculosis by using hydrotherapy.
• Juice therapy. Raw potato juice, may be taken three times daily with equal parts of carrot juice plus one teaspoon of olive or almond oil, one teaspoon of honey, beaten until it foams. Before using the potato juice, starch should be allowed to settle from the juice.
• Topical treatment may use eucalyptus oil packs, grape packs or grain alcohol packs.

Professional practitioners may also treat tuberculosis using cell therapy, magnetic field therapy, or traditional Chinese medicine. Fasting may be undertaken, but only with a doctor's supervision.

Allopathic Treatment

Drug Therapy

Five drugs are most commonly used today to treat tuberculosis: isoniazid (INH), rifampin, pyrazinamide, streptomycin, and ethambutol. Of the five medications, INH is the most frequently used drug for both treatment and prevention. The first three drugs may be given in the same capsule to minimize and treat active TB the number of pills in the dosage. As of 1998, many patients are given INH and rifampin together for six months, with pyrazinamide added for the first two months. Hospitalization is rarely necessary because many patients are no longer infectious after about two weeks of combination treatment. A physician must monitor side effects and conduct monthly sputum tests. In 2002, the Centers for Disease Control (CDC) worked with medical organizations to release new guidelines that better individualize the drug regimens received by TB patients depending on their disease symptoms and severity. Many can now receive once-weekly doses of rifapentine in the continuation phase of treatment.

The first large scale trial of a new agent to treat TB began in 2002. The promising new drug, called moxifloxacin, may mean a shorter treatment course for TB sufferers in the near future. It will also be tested in combination with rifapentine, and researchers believe that using the drugs together will mean a less frequent dosing schedule for patients.

Drug resistance has become a problem in treating TB. When patients do not take medication properly or for long enough periods of time, the TB organisms may become drug resistant. This makes the patient vulnerable to further infection and allows the TB organism to develop resistance.

Surgery

Surgical treatment of TB may be used if medications are ineffective. There are three surgical treatments for pulmonary TB: pneumothorax, in which air is introduced into the chest to collapse the lung; thoracoplasty, in which one or more ribs are removed; and removal of a diseased lung, in whole or in part. It is possible for patients to survive with one healthy lung.

Expected Results

The prognosis for recovery from TB is good for most patients, if the disease is diagnosed early and given prompt treatment with appropriate medications on a long-term regimen. According to a 2002 Johns Hopkins study, most patients in the United States who die of TB are older—average age 62—and suffer from such underlying diseases as diabetes and kidney failure.

Modern surgical methods are usually effective when necessary. Miliary tuberculosis is still fatal in many cases but is rarely seen today in developed countries. Even in cases in which the bacillus proves resistant to all of the commonly used medications, other seldom-used drugs may be tried because the tubercle bacilli have not yet developed resistance to them.

Prevention

Vaccination is widely used as a prevention measure for TB. A vaccine called BCG (Bacillus Calmette-Guérin, named after its French developers) is made from a weakened mycobacterium that infects cattle. Vaccination with BCG does not prevent infection, but it does strengthen the immune system of first-time TB patients. As a result, serious complications are less likely to develop. BCG is used more widely in developing countries than in the United States. Though the vaccine has been proven beneficial and fairly safe, its use is still controversial. It is not clear whether the vaccine's effectiveness depends on the population in which it is used or on variations in its formulation. Recently, efforts have been focused on developing a new vaccine.

Generally, prevention focuses on the prevention of transmission, skin-testing high-risk persons and providing preventive drug therapy to people at risk. Measures such as avoidance of overcrowded and unsanitary conditions are necessary aspects of prevention. Hospital emergency rooms and similar locations can be treated with ultraviolet light, which has an antibacterial effect.

INH is also given to prevent TB, and decreases the incidence of TB by about 60% over the life of the patient. INH is effective when taken daily for 6 to 12 months by people in high-risk categories who are under 35 years of age. About 1% of patients in preventive treatment develop toxicity. Because INH carries the risk of side effects (liver inflammation, nerve damage, changes in mood and behavior), it is important for its use to be monitored and to give it only to persons at special risk.

Unfortunately, failure of TB patients to complete the full course of their drugs adds to TB incidence and encourages development of drug-resistant strains of the disease. As scientists try to develop drugs that require shorter courses, physicians must work with patients to encourage compliance with their treatments. Even if symptoms go away, patients often have to continue their drug treatment for six months to be sure to stop the spread of their TB infection to others.

Resources

Books

Burton-Goldberg Group. Alternative Medicine: The Definitive Guide. Puyallup, WA: Future Medicine Publishing, Inc., 1994.

"Infectious Diseases Caused by Mycobacteria." Section 13, Chapter 157 in The Merck Manual of Diagnosis and Therapy, edited by Mark H. Beers, MD, and Robert Berkow, MD. Whitehouse Station, NJ: Merck Research Laboratories, 2001.

Merck Manual of Medical Information: Home Edition. Edited by Robert Berkow, et al. Whitehouse Station, NJ: Merck Research Laboratories, 1997.

Pelletier, Kenneth R., MD. The Best Alternative Medicine, Part II, "CAM Therapies for Specific Conditions: Tuberculosis." New York: Simon & Schuster, 2002.

Smolley, Lawrence A., and Debra F. Bryse. Breathe Right Now: A Comprehensive Guide to Understanding and Treating the Most Common Breathing Disorders. New York: W. W. Norton & Co., 1998.

Periodicals

"Changing Patterns of New Tuberculosis Infections." Infectious Disease Alert (August 15, 2002): 171–172.

"'Drug of Dreams' Preps for First Large-Scale Trail: Study to Begin this Year; Moxifloxacin to Debut Soon in Study 27." TB Monitor (July 2002): 73.

Efferen, Linda S. "Tuberculosis: Practical Solutions to Meet the Challenge." Journal of Respiratory Diseases (November 1999): 772.

Fielder, J. F., C. P. Chaulk, M. Dalvi, et al. "A High Tuberculosis Case-Fatality Rate in a Setting of Effective Tuberculosis Control: Implications for Acceptable Treatment Success Rates." International Journal of Tuberculosis and Lung Disease 6 (December 2002): 1114–1117.

"Guidelines Roll Out Two New Variations: Experts Give Both a Thumbs Up." TB Monitor (August 2002): 85.

Houston, H. R., N. Harada, and T. Makinodan. "Development of a Culturally Sensitive Educational Intervention Program to Reduce the High Incidence of Tuberculosis Among Foreign-Born Vietnamese." Ethnic Health 7 (November 2002): 255–265.

Kim, D. Y., R. Ridzon, B. Giles, and T. Mireles. "Pseudo-Out-break of Tuberculosis in Poultry Plant Workers, Sussex County, Delaware." Journal of Occupational and Environmental Medicine 44 (December 2002): 1169–1172.

Moua, M., F. A. Guerra, J. D. Moore, and R. O. Valdiserri. "Immigrant Health: Legal Tools/Legal Barriers." Journal of Law and Medical Ethics 30 (Fall 2002) (3 Suppl.): 189–196.

"New Drugs Sought for Top Killer of Young Women Worldwide." Women's Health Weekly (July 25, 2002): 20.

"Poor Patient Compliance Key to Drug Resistance in Tuberculosis." Pulse (July 1, 2002): 18.

Stauffer, W. M., D. Kamat, and P. F. Walker. "Screening of International Immigrants, Refugees, and Adoptees." Primary Care 29 (December 2002): 879–905.

Su, W. J. "Recent Advances in the Molecular Diagnosis of Tuberculosis." Journal of Microbiology, Immunology, and Infection 35 (December 2002): 209–214.

Organizations

American Lung Association. 432 Park Avenue South, New York, NY 10016. (800) LUNG-USA. .

National Heart, Lung, and Blood Institute (NHLBI). P. O. Box 30105, Bethesda, MD 20824-0105. (301) 592-8573. .

Other

New York State Department of Health. Communicable Disease Fact Sheet. nyhealth@health.state.ny.us.

University of Wisconsin-Madison Health Sciences Libraries. "Pulmonary Medicine" Healthweb. http://www.biostat.wisc.edu/chslib/hw/pulmonar.

[Article by: Amy Cooper; Teresa G. Odle; Rebecca J. Frey, PhD]

Definition

Tuberculosis is a chronic, infectious disease that primarily attacks the lungs.

Description

Tuberculosis (TB) is caused by a bacteria that primarily attacks the lungs. An individual may be "TB infected," meaning the bacteria are in the body but are in an inactive state, walled off behind scab-like structures that are the body's defense mechanism, or have "TB disease," when the bacteria actively spread throughout the body and can cause damage to the lungs or other organs. The severity of the attack depends on whether the bacteria spread from the lungs to other parts of the body. TB infection in the blood, the meninges (membranes around the brain and spinal cord), or the kidneys are the most serious. Children between the ages of six and 24 months are the most susceptible to meningitis; it is the chief cause of tuberculin death among children.

Transmission

The bacteria that causes TB, Mycobacterium tuberculosis, is transmitted by droplets when an infected person coughs or sneezes. It is not spread through kissing or other physical contact. Children nearly always contract the disease from an infected adult.

Demographics

In 2003, the Centers for Disease Control and Prevention (CDC) reported 14,874 cases of tuberculosis in the United States, or 5.1 cases per 100,000 population. The actual number of TB infections, however, is estimated to be much higher, as high as ten million. In 2002, there were 802 tuberculosis-related deaths. The District of Columbia had the highest rates of TB, with 14 cases per 100,000 people in 2003; Montana and Wyoming had the lowest rate, with 0.8 cases per 100,000 population. Children less than 15 years of age represented 6 percent of reported TB cases, and 15–24-year-olds represented 11 percent of all cases. Worldwide, TB cases are the rise, with nearly 8.8 million new cases a year being estimated by the World Health Organization (WHO).

Causes and Symptoms

Mycobacterium tuberculosis is a microscopic, rod-shaped bacterium. The majority of individuals who are infected with TB do not go on to have active disease. Active TB can be triggered when a person's immune system is weakened, such as from human immunodeficiency virus (HIV), malnutrition, or alcohol abuse.

Early symptoms of TB include unusual fatigue, fever, loss of weight, headache, coughing, and irritability. An infected child may have night sweats and cough up blood. In advanced stages, the patient will suffer persistent coughing, breathlessness, and fever. Many times TB is not diagnosed and becomes dormant; this is known as initial tuberculosis. In severe cases among young children between the ages of two and four, initial TB can be fatal. The disease can reoccur, or reactivate, during adolescence when resistance is low, and may disappear on its own or develop into serious lung disease.

When to Call the Doctor

Parents should contact their child's doctor if the child has been in contact with someone who has been diagnosed with or is suspected to have tuberculosis, or if the child exhibits the symptoms of the disease, particularly persistent fever, night sweats, and cough.

Diagnosis

Tuberculosis is nearly always diagnosed by tuberculin skin tests, although one can also be diagnosed by chest x rays and analysis of sputum (matter from the respiratory tract) smears and cultures. The most common tuberculin skin test is the Mantoux test, which consists of injecting a small amount of protein from the TB bacillus into the forearm. A reddening and swelling of the area after 24–72 hours signals the presence of TB. A negative result, however, may not necessarily exclude a diagnosis of TB.

Treatment

The disease is treated with a regimen of strong antibiotics such as Rifampin and Isoniazid for six months to two years. Because some strains of the disease are unusually drug-resistant, cultures are grown from the patient's bacteria and tested with a variety of drugs to determine the most effective treatment. In cases of strong drug-resistant strains, the child may undergo surgery to remove the infected areas.

Infants with TB are usually hospitalized but children and teenagers can generally lead active lives within two weeks of beginning medication. It is imperative that the mediation prescribed be taken faithfully.

Prognosis

With treatment, TB infection that is not drug resistant can nearly always be cured as long as patients are consistent with their medications and considerable lung damage as not already occurred. Drug-resistant TB has a lower cure rate. Without treatment, the disease will continue to progress; approximately one-half of untreated TB patients will die of the disease.

Prevention

Stopping the spread of tuberculosis is the most effective way of preventing its incidence among children. All adults who work with children should be screened regularly. In many communities, children are tested when they reach their first birthday and then at one-to-three year intervals throughout the school years. The medical profession is divided on the issue of screening; some physicians believe that the screening should be focused in areas of common occurrence or within high-risk populations such as foreign-born children. The practice of relying on parents to report results of the skin testing has also come under criticism from some members of the medical community.

While a vaccine for TB does exist (Bacille Calmette-Guerin or BCG vaccine), it is not widely available in the United States and has had conflicting reports about its efficacy. Being inoculated with BCG vaccine does not always prevent infection with the disease. The vaccine is only recommended for children in the United States if they live with someone who has active TB that cannot be treated or is drug-resistant.

Nutritional Concerns

Poor nutrition is closely related active tuberculosis; children with adequate nutrition are more resistant to the disease than those who suffer from malnutrition.

Parental Concerns

If a child has been infected with TB and is prescribed drug therapy to treat the disease, it is imperative that parents closely monitor their child to ensure that the medication is taken as prescribed; if the medication is not taken frequently enough or until it is no longer needed, drug-resistant TB can arise.

Resources

Books

Landau, Elaine. Tuberculosis. New York: F. Watts, 1995.

Periodicals

"TB on the Rise." Patient Care 38, no. 6 (June 2004): 9-10.

Young, Douglas B. and Brian D. Robertson. "TB Vaccines: Global Solutions for Global Problems." Science 284, no. 5419 (May 28, 1999): 1479.

Organizations

American Lung Association. 61 Broadway, 6th Floor, New York, NY 10006. (800) 548-8252. Web site: www.lungusa.com.

Centers for Disease Control and Prevention. 1600 Clifton Rd., Atlanta, GA 30333. (404) 639-3311. Web site: www.cdc.gov.

Web Sites

Division of Tuberculosis Elimination. "Reported Tuberculosis in the United States, 2003." Centers for Disease Control and Prevention. [cited September 12, 2004]. Available online at: .

Sharma, Sat. "Tuberculosis." eMedicine. January 14, 2003 [cited September 12, 2004]. Available online at: www.emedicine.com/aaem/topic464.htm.

[Article by: Mary McNulty Stephanie Dionne Sherk]

Tuberculosis (TB), an infectious disease, has been present throughout ancient and modern history. TB rates in the United States are on the decline after a resurgence from 1985 to 1992. However, TB continues to be a major killer in much of the world. The implications of this epidemic are global, as travel and migration are now part of everyday life.

Although the cause, diagnosis, and treatment and prevention of TB are known, paradoxically, the disease continues to increase as a public health challenge. Caused by a bacterium called Mycobacterium tuberculosis, TB spreads via an airborne route from an infectious person coughing, sneezing, laughing, or singing. The bacteria infect mainly other individuals who have frequent and prolonged contact with a contagious TB case.

History

TB's existence dates back many centuries. There are references to TB in third-century B.C.E. Chinese and second-century B.C.E. Indian texts; Plato and Hippocrates wrote about it around 400 B.C.E. TB was commonly known as consumption in Europe, a cause of death for hundreds of thousands in the late eighteenth and nineteenth centuries. This is when TB in close groups was first observed and assumed to have a genetic cause, since it was commonly seen in families.

In 1882 Robert Koch's discovery of Mycobacterium tuberculosis led to the recognition of TB as an infectious disease. This discovery also led to interventions for interrupting transmission from person-to-person.

Beginning in the late 1880s, TB patients were treated in sanitoria with various modalities, including exposure to fresh air, exercise, and nourishment. About 50 percent of patients recovered or had long-term remission. However, as is known today, their "cure" was not due to the treatments administered but perhaps to self-healing mechanisms.

In the early twentieth century, public health interventions became key in controlling the spread of TB in the cities, where TB was most prevalent. For example, Herman M. Biggs, General Medical Officer of New York City, actively catalogued lists of TB patients and enforced isolation and environmental mechanisms to control TB, including the opening of a TB hospital to quarantine patients. Between 1914 and 1923, the Metropolitan Life Insurance Company conducted the "Framingham Tuberculosis Project" using community nurses to visit the homes of its clients to do assessments, teach health practices, and collect data for research and policy-making purposes. The project was in response to a high rate of TB-related mortality among Metropolitan customers. As a result, mortality rates for TB in the Metropolitan pool declined by 68 percent.

Beginning in 1921, the Bacille Calmette Guerin (BCG) vaccine was used to prevent TB. Still used in many parts of the world but not in the United States, the vaccine is not effective, except perhaps in infants. The discovery of streptomycin in 1943 brought drug treatment for TB. Between 1943 and 1952, two more TB drugs, para-amino-salicylic acid (PAS) and isoniazid (INH), were discovered. Sanitoria began to close in the early 1970s, as TB could be now be treated on an outpatient basis, as evidenced by success in the decrease in TB rates with combined drug treatment and infection-control mechanisms.

Resurgence

By 1985, there were 22,201 cases of TB in the United States, the lowest number recorded since national case reporting began in 1953. However, rates then began to increase, until in 1992 cases peaked at 26,673. The human immunodeficiency virus (HIV) epidemic was a major contributor, as its victims are at higher risk for developing active disease once infected with TB bacteria. Migration from countries with high rates of TB added to the number. Also, improper or inadequate drug treatment for TB has led to drug-resistant strains. Finally, medical education stressed TB to a lesser degree in academic curricula, and funding and interest in TB-control programs had dwindled with decreased cases. Most authorities feel that the latter reason was the most important.

Response to the American TB resurgence resulted in increased funding for TB control programs. This gave greater access to TB treatment through health departments. The health departments were responsible not only for treating cases, but for surveillance, outreach, case management, and treatment for those who had been exposed to infectious TB cases. Directly observed therapy short course (DOTS), the observation of the ingestion of medication, has now become the basis for the worldwide standard of TB care. DOTS includes five elements: government commitment to sustained TB-control activities; case detection and self-reporting to health services; standardized treatment regimen of six to eight months for at least all confirmed infectious cases, with directly observed treatment (DOT) for at least the initial two months; a regular, uninterrupted supply of all essential anti-TB drugs; and a standardized recording and reporting system that allows assessment of treatment results for each patient and of the TB control program overall. DOTS is presently available to 25 percent of the world's TB patients, but its acceptance is slowly increasing. There was also an increase in TB educational interventions via the public health sector and medical schools. New drug trials did not create new drugs but created variations on existing drugs and regimens. TB rates began to decrease again in 1994, and as of 1999, they were at an all-time low of 17,528 cases in the United States. Globally, there are still eight million new cases of TB annually with three million deaths. Clearly, even with the exemplary level of achievement domestically, TB cannot be controlled anywhere unless it is controlled everywhere.

The Future

Although one of the Healthy People 2010 goals calls for TB elimination from this country, the United States is still far from that goal. Many interventions need to be continued despite falling rates. For other communicable diseases, effective vaccine development and the advent of new drug therapies has been key to disease control approaching elimination. The best course for TB elimination is to develop a vaccine and new drugs while continuing surveillance, treating TB patients who may infect others, treating those who have been infected but are not yet active cases, increasing TB awareness among health professionals, and performing targeted testing for TB infection among high-risk populations. This combination of medical and public health practice can make TB elimination a reality.

(SEE ALSO: Communicable Disease Control; Drug Resistance; Immunizations; Isolation)

Bibliography

Centers for Disease Control and Prevention (1995). Self-Study Modules on Tuberculosis. Atlanta, GA: Author.

—— (2000). Core Curriculum on Tuberculosis: What the Clinician Should Know, 4th edition. Atlanta, GA: Author.

Daniel, T. M. (1997). Captain of Death: The Story of Tuberculosis. Rochester, NY: University of Rochester Press.

Dublin, L. I. (1952). A Forty-Year Campaign against Tuberculosis: The Contribution of the Metropolitan Life Insurance Company. New York: Metropolitan Life Insurance Company.

Reichman, L. B. and Tanne J. H. (2001). Time Bomb: The Global Epidemic of Multidrug Resistant Tuberculosis. New York: McGraw Hill.

— RAJITA R. BHAVARAJU; LEE B. REICHMAN

For more information on tuberculosis, visit Britannica.com.

Tuberculosis was the leading cause of death in the United States during the nineteenth century, responsible at times for as many as one of every four deaths. Although the death rate from tuberculosis steadily declined beginning in the mid-nineteenth century, it persisted as a major public health problem well into the twentieth century, when programs of public health education, disease surveillance and diagnosis, and the availability of antibiotics and vaccination helped to curb its incidence. After World War II, the death rate was only a small fraction of what it was a century earlier, but by the 1990s, the emergence of tuberculosis strains resistant to antibiotics and the connections between tuberculosis and AIDS again made it a significant health concern.

Before the late nineteenth century, various names—including consumption and phthisis—were used to describe the dry, persistent cough, throat irritations, chest and shoulder pains, and difficult breathing accompanied by emaciation that characterized pulmonary tuberculosis. The incidence of tuberculosis grew dramatically in Europe beginning in the eighteenth century, and although its incidence in the United States was less severe, it had grown into the leading cause of death in the United States by the mid-nineteenth century. Other than being slightly more prevalent in women than men, the disease respected no boundaries, afflicting Americans of all ages, races, ethnicities, and social and economic stations.

Tuberculosis in Nineteenth-Century Life

While sudden and dramatic epidemics of cholera, diphtheria, smallpox, and yellow fever commanded public attention, tuberculosis quietly became a regular feature of nineteenth-century American life. Healers diagnosed tuberculosis on the basis of its physical symptoms, but they were at a loss to offer a definitive cause or cure for the disease. For much of the nineteenth century, it was thought that tuberculosis was hereditary, and therefore, that it was noncontagious and could not be transmitted from person to person. It was presumed that there was some familial disposition that made a person susceptible to the disease and that the interaction of the inherited constitution with environmental or behavioral "irritations," such as rich diets, sedentary occupations, and cold, wet climates, brought on the disease. The remedies emphasized changing the irritants, whether to a mild or bland diet, to an active lifestyle with exercise, or to a residence that was mild and dry. Between 1840 and 1890, thousands of Americans with tuberculosis, particularly from New England, became "health seekers," moving to where they believed the wholesome, restorative climates would give them relief. These "lungers," as tuberculosis patients were colloquially called, moved first to Florida, and later to the West and Southwest, settling in the deserts and mountains of Arizona, California, Colorado, and New Mexico. One in four migrants to California and one in three migrants to Arizona during the second half of the nineteenth century went looking to improve their health.

During the 1830s, tuberculosis was responsible for one in every four deaths, but by the 1880s, the mortality rate had declined to one in every eight deaths. In major American cities, the death rate from tuberculosis at the end of the nineteenth century (200 deaths per 100,000 population) was essentially half of what it was a century earlier. Improvements in diets and in living conditions, along with natural selection and genetic resistance in the population, contributed to the declining rates. Even as the mortality rates from tuberculosis declined in the general population, it persisted as a significant health problem among America's growing immigrant population, most of whom lived in the crowded, dank, and dirty tenements of America's urban centers—living conditions that were ripe for the rapid spread of the disease. The incidence of tuberculosis became increasingly associated with immigrants and the impoverished and the overcrowded living conditions they experienced.

Tuberculosis in the Age of Bacteriology

In March 1882, the German bacteriologist Robert Koch announced the discovery of Mycobacterium tuberculosis, the bacillus or bacterium that causes tuberculosis. But medical explanations attributing the cause of tuberculosis to heredity, climate, diet, lifestyle, poor ventilation, and other factors endured through the century and decades would pass before physicians were fully convinced that tuberculosis was contagious and could be transmitted between persons. The medical landmark of Koch's discovery accompanied the growing number of tuberculosis sanatoria being built in Europe and the United States after the 1850s and 1880s, respectively. The sanatorium movement emphasized a therapy regimen based on fresh air, proper diet, and rest, but they also served to remove and to isolate patients with tuberculosis from areas where they might infect others. Among the sanatoria were two founded by America's most prominent physicians of tuberculosis: Edward Livingston Trudeau established a sanatorium at Saranac Lake in the Adirondack Mountains of northeastern New York, and Lawrence Flick established a sanatorium at White Haven, in the Pocono Mountains of eastern Pennsylvania. Trudeau and Flick themselves suffered from tuberculosis, and learned of the benefits of an outdoor life in seeking a cure for their own afflictions. Trudeau's Saranac Lake sanatorium, founded in 1884, became a model for other sanatoria. Flick, believing that tuberculosis was contagious, advocated for a scientific approach to its diagnosis and treatment, as well as the registration of patients and the education of the public about the disease. In 1892, Flick founded the Pennsylvania Society for the Prevention of Tuberculosis, the first state organization in the nation devoted to the control and the elimination of tuberculosis. As other state societies against tuberculosis developed, Flick joined Trudeau, Hermann Biggs, William Welch, William Osler, and others to found in 1904 the National Association for the Study and Prevention of Tuberculosis (NASPT), the forerunner to the American Lung Association, which unified efforts, led public health education campaigns, and raised funds for research.

By the turn of the twentieth century, as the presence of the tubercle bacillus rather than the physical symptoms became the basis for diagnosis, the new understanding of what caused tuberculosis and how it was spread brought important changes in public health and the medical care of patients. The goal of Progressive Era public health work against tuberculosis was to improve social conditions and to control the behaviors that fostered the disease. Health departments instituted education campaigns that used films, posters, and lectures to dissuade individuals from practices that spread germs, such as spitting and coughing. In addition to maintaining clean, well-ventilated homes, the use of nonporous building materials such as metals, linoleum, and porcelain was encouraged over wood and cloth, which could harbor disease-causing germs. Public health officials inspected and fumigated dwellings that posed health risks, required physicians to report cases of tuberculosis, and forcibly isolated individuals who did not seek treatment. New diagnostic tests such as the tuberculin skin test and radiological examinations were used in mass screenings for tuberculosis, and new surgical therapies involving the collapse or partial section of the lungs were introduced. Infected individuals were required to seek treatment through a sanatorium or through a dispensary that engaged in disease surveillance and patient education.

Tuberculosis After World War II

The result of the far-reaching and aggressive public health campaign was that the incidence of tuberculosis, which had been steadily declining since the 1870s (when the mortality rate exceeded 300 deaths per 100,000 population), fell to unprecedented low levels by the 1930s (when the mortality rate fell below 50 deaths per 100,000 population). Disease mortality fell even lower (to 10 deaths per 100,000 population in 1954) after the development of an antibiotic, streptomycin, by the microbiologist Selman Waksman in 1943. Although other countries in the 1950s instituted vaccination campaigns using the Bacillus-Calmette-Guérin (BCG) vaccine, it was not adopted for wide use in the United States as public health programs emphasized the identification of patients exposed to the bacillus rather than universal vaccination against the disease.

Between 1954 and 1985, the incidence of tuberculosis in the United States declined 75 percent, and by 1989, public health officials confidently predicted its eradication in the United States by 2010 and worldwide by 2025, believing it would no longer pose a public health threat. These expectations were dashed as a worldwide pandemic of tuberculosis began in 1987 and the World Health Organization declared that tuberculosis posed a global emergency in 1993. The displacement of populations through immigration and political conflicts; the emergence of drug-resistant strains; the high rates of incarceration, homelessness, and intravenous drug use; the prevalence of mass air travel; the collapse of medical services in eastern Europe; the persistence of widespread poverty; and the progress of the AIDS pandemic, in which tuberculosis emerged as an opportunistic infection, all contributed to a worldwide public health crisis. By 2002, the World Health Organization reported that tuberculosis was the leading infectious killer of youth and adults and a leading killer of women, and that a third of the world's population was infected with the tuberculosis bacillus. In response, nearly 150 countries, including the United States, agreed to adopt the Directly Observed Treatment Short-Course (DOTS) system in which countries would promote public health programs of case detection, standardized treatment regimens using multiple drugs, patient surveillance to monitor compliance, and the forcible detention of noncompliant patients. Once thought to be on the verge of eradication, in 2002 it was not known if and when the worldwide incidence of tuberculosis would return to levels experienced only a half century before.

Bibliography

Bates, Barbara. Bargaining for Life: A Social History of Tuberculosis, 1876–1938. Philadelphia: University of Pennsylvania Press, 1992.