- As drugs to treat tuberculosis became more effective,
the disease grew more resistant, leading to a deadly new strain that is
riding increases in immigration and travel.
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- The war year of 1944 was an important one in the fight
against tuberculosis (TB). Up to that time a TB diagnosis usually meant
a long stay in one of the country's more than 600 sanitariums. Or death.
But with the discovery of streptomycin, treating TB became a matter of
taking a regimen of pills. By the early 1970s new cases of the disease
were an oddity among native-born Americans. Indeed the medical community
predicted the disease would be eradicated in the United States by 2000.
- Then in the
mid-1980s, with the epidemic of the human immunodeficiency virus (HIV)
weakening immune systems, TB made a comeback. The medical community redoubled
its efforts and, by 1992, the numbers were on the decline. When the next
surge of TB comes, will modern medicine be as successful?
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- While there's
still a 95 percent treatment rate, as the drugs to treat TB became more
readily available the disease has grown more resistant. Fifty years after
medicines were created to cure TB, the bacteria has learned to fight back
against such drugs as isoniazid and rifampin. Tuberculosis mutated into
a new strain, called multi-drug resistant TB (MDR-TB).
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- This new strain
is as deadly as it is untreatable, according to a recent study published
in Chest, the peer-reviewed journal of the American College of Chest Physicians.
In a controlled study of patients with MDR-TB, 32 percent died even though
they received intense medical attention. "We have a potentially disastrous
public-health problem if we don't get serious about treatment," says
physician and coauthor of the study, David Ashkin of the A.G. Holley State
Tuberculosis Hospital in Lantana, Fla.
- How are patients
contracting MDR-TB? More than 53 percent in the study "acquired"
the disease "through a combination of inadequate professional care
and unpredictable patient behavior," says John Sbarbaro, a professor
at the University of Colorado Health Sciences Center. When the regimen
of drugs is not completed by the patient, TB can mutate into MDR-TB. While
many patients simply stop taking their medicine before the required six-month
regimen is completed, others are victims of bad medicine and/or bogus pills.
In some developing nations, the supposed medicine is nothing more than
a sugar pill. And in some places the full complement of drugs is not always
available. The result is the same: a more virulent disease is born.
- Worse, the
drug regimen for treating the mutated MDR-TB takes anywhere from 18 to
24 months and includes toxic drugs with debilitating side effects. In some
parts of the world up to 14 percent of new TB cases are MDR, notes Mario
C. Raviglione of the World Health Organization (WHO) in Switzerland. "If
anything, we are losing the battle worldwide," Sbarbaro says.
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- The other 47
percent of MDR patients in the Chest study acquired the mutated strain
the old-fashioned way. That is, they inhaled the pulmonary disease, sharing
air with someone who already was infected. According to Sbarbaro, this
demonstrates that "the old belief that drug-resistant organisms are
not as contagious as fully sensitive tubercle bacilli was, and is, wrong."
- Not that the
traditional TB isn't deadly enough. On average it claims more than 2 million
lives a year worldwide, according to the WHO. Nearly 70 percent of those
with active TB will die of it if untreated; for those who also have HIV,
the numbers are even higher.
- While TB outbreaks
usually occur in damp, sunless environments such as prisons and refugee
camps, there are documented cases of the bacteria being transmitted on
trans-Atlantic flights. Typically, someone has to breathe the uncirculated
air of an infected person for anywhere from six to eight hours for transmission
to occur, TB researchers estimate.
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- Since transmission
occurs fairly regularly, more than one-third of the world population has
TB. But there's a difference between being infected with TB and having
"active TB," public-health officials caution, because 90 to 95
percent of the people infected with TB don't develop the full-blown disease.
- Treating any
contagious disease can turn into a privacy debate because the rights of
the individual come into conflict with the health of the community, says
physician Martin Siegel of the Swedish Hospital Medical Center in Seattle.
In addition to these concerns, there's the potential to politicize the
issue because many of the high-risk groups are immigrant populations. "But
public-health officials don't think like that," Siegel adds. They
are concerned with "what's the best way to treat the patient and also
address the public-health concerns."
- For diseases
such as TB, all 50 states have public-health ordinances requiring even
unwilling patients to get treatment. But these ordinances only apply to
those who have been diagnosed, and many TB carriers, especially undocumented
aliens, are hesitant to seek proper medical attention. When a carrier moves
to another state, Sbarbaro says, "there's no way to track them."
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- One of the
problems with treating TB is that "as soon as you start to feel good,
you stop taking your drugs," Sbarbaro explains. Since the cure rate
is higher significantly for inpatient treatment, public-health experts
such as Sbarbaro argue that we need to consider the possibility of "chemical
isolation" - code for confining these patients in sanitariums. "Once
MDR-TB is detected, it is crucial to recognize that every physician becomes
a public-health official," he wrote in a Chest editorial.
- One possible
solution is to stop TB at the U.S. border with tighter immigration standards.
In 1999, 43 percent of active TB cases in the United States were among
the foreign-born, according to the Centers for Disease Control and Prevention.
But many experts in the public-health community argue that keeping TB from
crossing the border is as impossible as stopping illegal immigration.
- Under the Immigration
and Nationality Act any alien who is determined "to have a communicable
disease of public-health significance" is to be prohibited from entering
the country. For immigrants seeking permanent residence in the United States,
a doctor's checkup is required before a visa is approved. If an applicant
is diagnosed with a communicable disease such as TB or HIV, the applicant
is supposed to be disqualified from entry.
- But there have
been allegations that some "panel-approved physicians" can be
bribed or persuaded to issue clean bills of health for sick applicants,
Sbarbaro says. In response to this corruption, some panel-approved physicians
have been decertified, but an official at the U.S. Bureau of Consular Affairs
tells Insight that no one knows how widespread the problem is.
- Absent a clean
bill of health a prospective immigrant is denied entrance unless the U.S.
attorney general provides a waiver. In the past, such waivers have been
granted for international HIV conferences, the Gay Games and to accommodate
particular groups of political refugees.
- While the Immigration
and Naturalization Service (INS) requires a doctor's approval of applicants
for permanent status, the 22 million foreign visitors to the United States
each year are trusted to report their medical histories accurately on their
visa paperwork.
- In addition,
the millions of Americans who travel abroad are not screened upon re-entry,
leading many public-health officials to conclude that the best way to treat
TB in the United States is to treat it worldwide. "We are not isolated.
We are not an island," Sbarbaro reminds Insight.
- Worldwide,
there were an estimated 8.4 million new tuberculosis cases in 1999, up
from 8 million in 1997, according to the WHO 2001 Report on Global Tuberculosis
Control. While India and China rank atop the list of countries with traditional
TB problems, Eastern Europe and the former Soviet satellite states now
have the highest incidences of MDR.
- Treating the
problem may not be as easy as flooding the world with cheap TB drugs. "We
are against parachuting drugs into countries that do not have the systems
to handle them," says the WHO's Raviglione. While the cost of first-line
drugs is as low as $7 for a six-month treatment, even second-line drugs
for MDR cost $10,000 to $15,000. Through an arrangement with the WHO and
pharmaceutical companies there's now a plan to get drugs into countries
at discounted prices.
- But these discounted
drugs are only made available to countries that prove they can distribute
and administer them responsibly. "We are telling some countries that
they are not ready," Raviglione explains. "Tragically, doctors
in these countries either have to watch their patients die or watch them
live and pass on the chronic disease to others. But there's no other way"
to stop the global spread of MDR.
- While there
still are many political concerns about committing patients to TB specialty
centers, scientific evidence suggests that full-time care is the most effective
way to eradicate the disease. Sbarbaro points out, "Forty-five percent
of patients who received care in community-care settings died versus 18
percent of patients who received care in the inpatient-treatment facility."
- As for MDR,
if we don't treat it soon, Raviglione says, "We are bound to fail,
and that could be disastrous."
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