The Two Faces Of Tuberculosis
Tuesday, June 19, 2007
The story of Andrew Speaker's infection with "extensively drug-resistant" tuberculosis -- with its weird improbabilities and misunderstood messages -- has provided a crash course in one of the 21st century's least recognized health threats.
The wandering, love-struck and tubercular lawyer accomplished in two weeks what a small army of epidemiologists and advocates has not in a decade: given drug-resistant TB a Paris-Hilton-like spot in the popular consciousness. He has added "XDR-TB" to the vocabulary of American households alongside pandemic flu, anthrax and SARS.
"TB is a weapon of mass destruction, with 2 million deaths a year," said Henry M. Blumberg, a TB expert at Emory University School of Medicine in Atlanta. "It is a huge global public health problem, and it usually gets ignored."
Speaker's story has struck chords that will resonate long after its details are forgotten.
The case marks the latest revision of the world's evolving notion of health risk -- and what to do about it. It illustrates what may be necessary to fight epidemics that, unlike classical plagues of history, can take decades to develop. The federal government's first use of an "order of isolation" since 1963 also showed what a long arm in a white coat is willing to do to prevent infections that probably weren't going to happen anyway -- but would be catastrophic if they did.
Perhaps most important, the case shows what can happen when the affluent precincts of the global village ignore what is happening in the poorer ones.
That last point is the one that Richard E. Chaisson, an expert in drug-resistant tuberculosis at Johns Hopkins University's Bloomberg School of Public Health, hopes will not get lost.
The existence of XDR-TB in the lungs of a young, healthy Atlanta trial lawyer is evidence that the world needs to do a lot better at finding, treating and preventing tuberculosis in poor countries. That is where most of this year's 8.9 million new cases will occur -- 424,000 of them resistant to two drugs (multi-drug-resistant, or MDR) and 27,000 resistant to at least four (extensively drug-resistant, or XDR). They are the direct result of inadequate treatment.
"I am concerned that what will happen is that a lot of money and attention will be spent on homeland security issues, which have little to do with tuberculosis control," Chaisson said. "I am worried that the focus may be on biosecurity rather than on the problem itself."
What's urgently needed, he said, are tools for diagnosing TB and drug resistance that don't require fancy laboratories, as well as drugs both to treat the resistant cases and to make treatment of the regular cases quicker.
The subtleties and contradictions of Speaker's case underscore the challenge of tuberculosis.
The 31-year-old did not have any of the common risk factors for TB. He was not homeless or a recent immigrant. He had not been in prison. He was not poorly nourished or infected with the AIDS virus. Where he caught TB is a mystery. It's possible he was infected last year while visiting hospitals in Vietnam, where he did charity work with the Rotary Club.
Whatever the source, his illness is the result of the unwitting exposure of a healthy person to an ill one -- the very scenario that health authorities in Fulton County, Ga., sought to prevent when they told him not to fly to Europe for his long-planned wedding.
However, it was always a long shot that he would infect anyone else.
His case was "smear-negative" -- no organisms were visible when fluid from his lungs was examined under a microscope (although clearly they were in there because they grew out in lab culture). He felt well and wasn't coughing, which is the way the bacteria spreads in most "pulmonary," or lung-involved, cases. He had not infected his fiancee, family members or co-workers. His physician -- and apparently also the local health authorities -- did not think he needed to be isolated while awaiting treatment.
Nevertheless, people like Speaker aren't harmless. In a study of five years' worth of new TB cases in San Francisco, 17 percent were traced by DNA fingerprinting to a "smear-negative" infected person. The concern about air travel arose from studies in the 1990s showing that TB patients occasionally infect other passengers on long flights, with the people sitting within two rows of them at highest risk.
Despite the improbability of Speaker's infecting anyone else, the consequence of such an event would be extreme, especially when tests revealed his case was not only drug-resistant, but "extensively" so. Only one-third of XDR-TB patients are cured; the rest die.
Such "low-probability/high-consequence" scenarios are among the trickiest in medicine. It appears that Speaker concentrated on the probabilities; public health authorities were more concerned with the consequences.
The latter was dramatically clear when the federal Centers for Disease Control and Prevention tried to stop Speaker during his honeymoon in Italy.
A former CDC tuberculosis specialist working there notified Italian health officials and determined that Spallanzani Hospital in Rome, which has experience treating XDR-TB cases, had an isolation bed available. Simultaneously, a CDC quarantine officer in Atlanta tracked down Speaker and told him by phone to stay put.
Although Speaker's risk to others was almost certainly still small, transmission of the infection at this point would have been unforgivable. So unforgivable that the CDC didn't feel it was safe to send one of its airplanes to get him because none had air-filtering systems that would fully protect the crew.
"You can't be faulted if you take the most conservative approach. I saw this in the anthrax days," said Eddy A. Bresnitz, New Jersey's state epidemiologist, who helped direct the response to the 2001 bioterror attack that caused, among others, six cases of anthrax in New Jersey postal workers.
"CDC is always going to exercise the 'precautionary principle,' that you take protective measures even though you may not be certain how protective they will be, or how much further they may reduce risk," he said.
But extreme caution can have unintended consequences.
The prospect of being hospitalized in Italy for an indeterminate period clearly alarmed Speaker. He and his bride bolted -- back home, where he'd been told he would have the best shot at a cure.
Exactly what was said before they made this decision isn't known. CDC officials say they laid out options for getting him home. Nevertheless, Speaker's action highlights how much the perceptions of single patients can affect the public health.
"It may be that the most effective way to safeguard the health of the public at large is to assure the person who is sick -- or, in this case, the carrier -- that he will not be abandoned," said Johns Hopkins bioethicist Nancy Kass.
Whether it was necessary to slap a detention order on Speaker soon after he reentered the United States has become a subject of debate in public health circles.
Some believe the action violated a principle enunciated in another context by Louisiana State University legal scholar Edward P. Richards: that "the state demonstrate that the action ordered is intended to prevent harm in the future, not to punish for past actions, and that the action is reasonably related to the public health objective." They argue the detention order was punitive, as Speaker agreed to go straight to a New York City hospital when a CDC doctor reached him by phone soon after he reentered the United States via Canada.
Others believe the handling of someone who had twice defied medical advice was justified. Part of the reason, they argue, is that XDR-TB can only be fought one case at a time.
Unlike pandemic flu or SARS, XDR-TB does not emerge explosively. It cannot be stopped by halting or limiting the movement of whole populations. Moreover, there is no vaccine that can be given to masses of adults to prevent infection.
Instead, TB can be controlled only by the meticulous care of individuals, who must take medicine -- often a daily handful of pills -- for at least six months, and sometimes for as long as three years. Those who quit taking the medication once they started feeling better are responsible for the emergence of drug-resistant strains. Stopping a TB epidemic requires the prolonged cooperation -- either willing or enforced -- of every patient.
If every person with XDR-TB acted as Andrew Speaker did, the result would be calamity on a global scale. His detention -- whether that was the intent or not -- sent the world that message. ·