March 16, 2001
Tuberculosis Is Back, and Deadlier Than Ever
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
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:
of the head or neck
or Hodgkin's disease
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:
bad cough that lasts longer than 2 weeks
in the chest
up blood or sputum (phlegm from deep inside
Other symptoms of TB disease are:
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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Jonathan Freedhoff, M.D., is the Chief Resident in Family Medicine
at the University of Ottawa Civic Hospital Campus and is completing
a fellowship in emergency medicine. He's currently involved in a
two-month project on Baffin Island, in the High Arctic region, where
he's one of four family doctors working with the Inuit population.