16 de jul. de 2012

Legionella - 36 anos em Julho de 2012

Como tudo começou em Julho de 1976

In late July 1976, American Legionnaires returning from a state convention in Philadelphia began to fall ill with mysterious symptoms: pneumonia and fevers topping 107 degrees.

By early August, news organizations across the country were reporting that 6 to 14 of the men in Pennsylvania had died. Others were in hospitals fighting for their lives. No laboratory tests could determine the cause of their illness, which quickly became known as Legionnaires’ disease. No one knew the health status of the 10,000 other convention participants.
As the news began to break, 36 years ago this week, Americans were primed for the threat of an epidemic. The Ford administration was making plans to vaccinate every American against a new strain of influenza, known as swine flu, after repeated warnings from government officials that a devastating epidemic could strike without warning. Michael Crichton’s “Andromeda Strain” had become a best seller. And some scientists were calling for a moratorium on laboratory efforts to genetically engineer microbes for fear they might create a monster germ.
These factors made the unexpected attack on American veterans, which occurred shortly after the country’s bicentennial celebration, front-page news.
When I first heard about the mysterious cases from news agency bulletins on Aug. 2, I initially viewed them with some skepticism. A few months earlier, Dr. Leonard Bachman, the Pennsylvania health secretary, issued a news release saying that a staff member, Dr. Buford S. Washington, had discovered an often fatal new disease, pantosomatitis, that was spreading throughout the eastern United States. Looking into the claim, I found there was no documented case and no such disease.
Disease outbreaks were familiar territory for me. Before coming to The New York Times, I’d been an Epidemic Intelligence Service officer at the Communicable Disease Center, now the Centers for Disease Control and Prevention, in Atlanta. If the Legionnaires’ outbreak had occurred a decade sooner, I might have been one of the investigators sent to Pennsylvania.
Health officials there urged the public not to panic, and some initially denied that the cluster of cases was an outbreak of an infectious disease. But behind the scenes, the same officials were bracing themselves for a medical catastrophe.
“We thought we might be faced with an unprecedented condition in modern medicine, one for which we had no really effective antibiotics, drugs or therapy,” Dr. Bachman told me in 1976. Because there was no way to predict how many more Legionnaires would fall ill, Dr. Bachman said he had contemplated seizing control of all hospitals in the state and imposing quarantines.
It took six months to determine that the illness had been caused by a bacterium, Legionella pneumophilia, which we now know usually succumbs to the timely prescription of proper antibiotics. The bacterium, which in this case was apparently spread from the hotel’s air-conditioning system, is a cause of pneumonia and other illnesses worldwide.
The investigation that solved the mystery took an array of surprising twists and turns. It revealed the strengths and weaknesses of the nation’s health system in response to an outbreak from an unknown agent.
Some lessons learned from the outbreak improved investigations of later outbreaks likeavian fluSARS and the deliberate release of anthrax spores in the postal system shortly after the Sept. 11 attacks. But many authorities have not learned other important lessons, like the need for more effective communication.
Intense news coverage of the Legionnaires’ outbreak continued for weeks, providing one of the rare opportunities for the public to see how medical detectives work and how scientists make discoveries.
The epic challenged the widespread notion that medicine was all-knowing, able to lick almost any problem, and that antibiotics and vaccines had turned once lethal infectious diseases into minor threats.
The news coverage also marked a turning point in journalism’s efforts to hold officials accountable for their response to epidemics that can threaten the lives of thousands of people, as well as tourism, international trade and world economies. News about the outbreak led to the temporary closing of the Bellevue-Stratford Hotel, a Philadelphia landmark that was the headquarters of the American Legion convention and a focus of suspicion about the spread of the bacterium.
The C.D.C. sent 20 epidemiologists — the largest squad of medical detectives to investigate an outbreak in the federal agency’s history — to Pennsylvania where they joined scores of state health workers.
The sleuths fanned across the state to review the medical records of all the ill Legionnaires and to study the autopsy findings in the fatal cases. Epidemiologists also checked every hospital to identify new cases and interview patients’ families and doctors, in part to determine whether one or more Legionnaires might have taken the illness to Philadelphia.
On Aug. 2, when news agencies began issuing dispatches, a quick look convinced me that the Legionnaires’ cases were real, not another false alarm. Late that evening, I finished my first article about the still-unnamed mysterious disease.
Then I drove to Harrisburg, listening to the radio to keep me awake but unable to escape the repetitious news accounts about the outbreak, the speculation that the illness was swine flu and the safety concerns about visiting Philadelphia.
The Times handled the story more cautiously than radio and television. My article, on Page 12, was not even included in the news summary.
Over the next few days, the toll of the illness rose. The final count was 221 cases, including 34 deaths.
As a physician, I wanted to see the patients who were recovering or fighting to stay alive and to learn what leads were being developed from the interviews.
In Chambersburg, Pa., I joined Dr. Stephen B. Thacker, then a rookie in the C.D.C. epidemiology program. We interviewed a Legionnaire, Thomas A. Payne, 48, whose temperature rose to 107.4 degrees before he was put in a cooling blanket.
We felt safe entering his room because we followed standard precautions, wearing yellow masks, white gowns and gloves. In introducing us, Dr. Thacker told Mr. Payne that he “was part of the medical team investigating this weird disease.”
Dr. Thacker, who later became the head of the epidemiology program, asked Mr. Payne a number of questions related to the onset of his illness, how he had felt since, where he had stayed in Philadelphia and what convention events he had attended. Then Dr. Thacker sent the information to colleagues in Harrisburg.
Two weeks later, I interviewed another hospital patient who had driven with four Legionnaires from their home in Saltillo, Pa., to Philadelphia where they had stayed at the same hotel and were together for nearly all the convention events. But no one could figure out why only that patient had developed the disease.
The anecdote illustrates the kinds of dead ends that epidemiologists, like criminal detectives, encounter and that scientific journals rarely publish. They and other factors create a false impression that investigations and discoveries are simpler than they really are.
A week into the investigation, health officials were relieved as a second outbreak failed to develop among those attending an international religious meeting in Philadelphia and no spread of the ailment occurred from Legionnaires’ patients to their families and friends.
Tests also excluded all forms of influenza as a cause of the outbreak. “All of us can breathe a sigh of relief it was not the flu,” said Dr. David J. Sencer, then the C.D.C. director.
If not influenza, what was the illness? Earlier tests had ruled out poisoning from 17 metals. But experts in a variety of specialties who were not connected with the outbreak had called or written to me and health officials to suggest a number of toxins.
Stumped, health officials re-examined the possibility of other toxins or poison gases. One poison, nickel carbonyl, was a long shot that health officials took seriously, only to be embarrassed by flaws in the collection of the tissues for testing. The initial nickel findings were ruled invalid because of probable contamination from the use of metal instruments in autopsies. Pathologists were then ordered to use plastic knives.
Reports of the lapses in investigation technique jarred public confidence about the ability of health departments to detect outbreaks from hazardous chemicals. The flaws also led to a Congressional hearing in the fall on the medical investigation, causing federal and state health officials further embarrassment.
By winter, many of the authorities said the outbreak’s cause was definitely not a bacterium and that it would never be known. But the doubters overlooked the importance that human factors like compulsiveness, embarrassment and public pressure can play in solving scientific riddles and making discoveries.
At Christmastime in 1976, Dr. Joseph McDade, a C.D.C. laboratory scientist who had tested specimens from the outbreak, was harshly criticized at a party for his agency’s failure to solve the mystery.
Dr. McDade said his usual custom at that time of year was to “tidy up loose ends,” so when he went to his laboratory “to put to rest some hunches about something” he had seen in the specimens, the insult lurked in the background.
Within a month, Dr. McDade had identified the culprit and showed that Legionnaires’ was a newly recognized old disease. The bacterium had been isolated at least twice before by different groups of researchers at the Walter Reed Army Institute of Research in Washington starting in 1947. Each group believed it was dealing with a bacterium that affected animals, not humans.
Dr. McDade’s discovery quickly led scientists to document a number of earlier outbreaks in Pontiac, Mich.; Washington; and elsewhere. Legionnaires’ disease now accounts for an estimated 18,000 hospital admissions in this country each year, and C.D.C. scientists have said that doctors miss the diagnosis in many more patients. Most outbreaks and cases have been traced to contaminated water in places like shower heads, air-conditioning systems and medical respiratory devices. The largest outbreak, in Spain in 2001, affected nearly 700 people.
The Legionnaire bacterium can produce two forms of illness that begin with flulike symptoms. One, Legionnaires’ disease, goes on to produce pneumonia and systemic illness. The other, Pontiac fever, produces only a mild illness. Why the same bacterium causes two distinct illness patterns is not known.
Seamless teamwork between epidemiologists and laboratory scientists can be a potent weapon in solving disease outbreaks caused by known and unknown agents. But the teamwork in the Pennsylvania outbreak was porous, as lapses in investigation technique showed.
From the start, the investigation encountered a number of problems, some beyond their control. One was that the American Legion had no registration list of conventioneers, leaving no easy way to contact attendees to check on their health.
In investigating outbreaks, epidemiologists often develop questionnaires, in part to make statistical comparisons between those who become ill and those who do not.
Another aim is to determine the priority in performing laboratory tests to determine the cause of an illness. But the longer the delay in starting this medical sleuthing, the fuzzier people’s recall of events becomes. A problem was that health officials could have learned of the outbreak earlier than they did. For example, a physician in Pennsylvania called health officials on July 30, a Friday afternoon, to report a Legionnaire with possible typhoidfever. It was too late in the day, call back on Monday, a nurse said.
The episode illustrated that many health departments did not provide the type of 24/7 coverage for calls and emergencies that hospitals and doctors did. Now more health departments provide such coverage.
Still another problem was that Philadelphia health officials learned belatedly about an earlier outbreak of 19 cases of an illness similar to Legionnaires’ disease, including three deaths. It affected members of the Independent Order of Odd Fellows in 1974 after they had visited the Bellevue-Stratford. The cluster was not reported until after news of the Legionnaires’ outbreak in 1976.
However, there were widespread complaints about a number of issues over which health officials had some control. One was the lack of coordination between investigators from federal, state and local health departments and determining which was in charge.
Doctors who cooperated in providing information and specimens from Legionnaires’ patients said they had received little feedback from health officials. For example, some doctors said antibiotics were effective in their patients and urged wider use of them in the outbreak. But health officials gave no advice, largely because they could not scientifically evaluate the effectiveness of the antibiotics among the patients quickly enough.
The issue of providing such evaluations of therapy during an outbreak remains an important problem; many doctors and others lodged the same complaint against the C.D.C. in the anthrax outbreak in 2001. Some critics said they learned more about the outbreak from news organizations than from the agency.
In the case of Legionnaires’, persistent pressure from the news media, a number of health officials said later, helped hold them accountable and to spur scientists to do what they rarely had done in other unsolved cases and outbreaks — taking a crucial second look that solved the Legionnaires’ outbreak.

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