March 16, 2001

PUBLIC HEALTH
Tuberculosis Is Back, and Deadlier Than Ever
nce a major killer, tuberculosis (TB) is back, and it now claims more than 2 million victims per year worldwide. In fact, one-third of the world population is currently infected with the deadly respiratory disease. It has been at least 30 years since this disease was a serious threat. In the 1940s, a treatment for TB was discovered; with widespread use, the disease was brought under control. Now, with accelerating global travel and trade and with the emergence of drug-resistant TB, it's going to be hard to get rid of the disease.

The Human Condition   By Jonathan Freedhoff, M.D.

Tuberculosis is an extremely contagious disease caused by infection with mycobacterium tuberculosis. TB spreads through airborne droplets expelled every time an infected individual speaks, coughs, sneezes, or spits.

Left untreated, each person with active TB will infect an average of 10-15 people each year. The World Health Organization has declared this situation a global emergency and estimates that in the next 20 years TB will infect nearly 1 billion more people, causing 200 million people to grow sick and 35 million to die.

Why TB, why now?

So why is TB making a comeback? There are three main factors involved in the resurgence: human immunodeficiency virus (HIV), resistant TB strains, and global travel.

• HIV. HIV and TB are an often-lethal combination because one feeds off the other. HIV weakens the body's immune system and increases the likelihood of exposure to TB, resulting in an active infection. This process is glaringly evident in sub-Saharan Africa, where one in 40 individuals are infected with HIV. Also, TB rates have more than doubled in the area, with more than 1.5 million cases occurring annually. And it's not just Africa that is at risk. With the rates of HIV rapidly rising in Asia and the Indian subcontinent, where more than 60 percent of the world's population resides, we may soon see an epidemic of co-infection that will make Africa's 1.5 million cases seem tiny in comparison.

• Resistant TB. Unlike many other infectious diseases, treatment for TB involves using multiple medications for an extremely long time. At a minimum, treatment of active TB involves the use of four separate medications for 24 weeks. As with any antibiotic regimen, missed doses and curtailed treatment courses lead to resistant strains of bacteria. Multidrug-resistant TB (MDR-TB), which first surfaced in the mid- to late-1980s, is defined as tuberculosis that is resistant to two or more of the primary first-line treatment agents used to treat standard TB.

  Risk and Symptoms of Tuberculosis, from the Centers for Disease Control and Prevention People at Risk Babies and young children often have weak immune systems. People infected with HIV, the virus that causes AIDS, have very weak immune systems. Other people can have weak immune systems, too, especially people with any of these conditions: substance abuse diabetes mellitus silicosis cancer of the head or neck leukemia or Hodgkin's disease severe kidney disease low body weight certain medical treatments (such as corticosteroid treatment or organ transplants) Symptoms of TB Symptoms of TB vary depending on where in the body the TB bacteria are growing. TB bacteria usually grow in the lungs. TB in the lungs may cause the following: a bad cough that lasts longer than 2 weeks pain in the chest coughing up blood or sputum (phlegm from deep inside the lungs) Other symptoms of TB disease are: weakness or fatigue weight loss no appetite chills fever sweating at night

  The cost of treating MDR-TB is staggering as its treatment can involve taking upwards of six medications daily for one-and-a-half to two years. In fact, treatment costs of resistant TB are often more than 100 times as expensive as the treatment of drug-susceptible TB, which costs a minimum of $2,000 per patient. With the vast majority of TB occurring in developing nations, the high cost of therapy leads to inconsistent or partial treatment. In turn, this leads to increased drug resistance.

• Global travel. It is estimated that in industrialized countries, roughly 40 percent of TB cases are among foreign-born people. Once again, we see that public health is a global issue and cannot be viewed in isolation. Globalization, transnational migration, and tourism will continually bring TB across our borders. Therefore, strategies must be developed that address the problem and help treat patients across international lines.

Connecting the DOTS

The World Health Organization has come up with a strategy that, to date, has proven extremely effective in treating tuberculosis. Directly Controlled Treatment, Short-Course -- known as DOTS -- is a six- to eight-month government-sponsored treatment for infected individuals. A trained medical staff directly supervises patients' drug treatments, ensuring that there is no variance in dosage amount and that treatment is completed. When used properly, DOTS therapy has been shown to produce cure rates of up to 96 percent and to help prevent the development of resistant TB strains. Unfortunately, in 1999 only 24 percent of the world's TB patients were treated using the DOTS strategy. The sad truth is that most countries simply do not have the human or monetary resources to implement directly observed treatment regimens.

You and TB

Tuberculosis is something that should concern you. MDR-TB has been reported in every country surveyed by the World Health Organization, particularly where DOTS is not a standard treatment practice. Widespread outbreaks of MDR-TB may eventually mean that TB becomes resistant to all of our known medications. Holding your breath might be your only defense, unless our industrialized nations see the wisdom of helping prevent this looming epidemic.

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