ews Analysis

WASHINGTON, Nov. 25 ?When a letter containing anthrax was mailed to a Senate office last month, the federal Centers for Disease Control and Prevention said antibiotics were not necessary for postal workers in the nation's capital, and two of the workers died. But when a 94-year-old woman in Connecticut contracted a lethal case of anthrax last week, the disease control agency quickly recommended treatment for postal workers, even though there is no evidence as yet that a contaminated letter was the source of her infection.

Those disparate responses, coming one month apart, illustrate how much the C.D.C. is learning ?and how much it had to learn ?in trying to manage what may be the most complex disease outbreak in its history.

Widely regarded as the world's premier public health organization, the agency has drawn praise for devising a treatment plan that has greatly reduced the fatality rate from inhalation anthrax, the deadliest form of the disease. But the agency has also been caught short, critics say, by a failure to prepare adequately for bioterrorism. It has been forced to rely on its experience with anthrax as a naturally occurring illness. That experience is limited because the disease is so rare, and it is of little value in a situation in which germs have been manufactured into potent weapons and spread intentionally by someone who wants to kill.

"Amidst all of the experts, virtually none have taken care of a case of anthrax," the disease control centers' director, Dr. Jeffrey P. Koplan, said in a recent interview. "Nor do we have experience with anthrax being sent through the mail."

So as the investigation takes new twists and turns, the agency is left, in Dr. Koplan's words, trying to put together bits and pieces of information "into a coherent scientific picture, and at the same time trying to shape public health policymaking."

The death of Ottilie W. Lundgren, the elderly Connecticut woman who last week became the fifth American to die of inhalation anthrax in the last two months, poses yet another daunting challenge for the disease control centers. Its epidemiologists are already struggling to unravel another anthrax mystery, that of Kathy T. Nguyen, the Bronx hospital worker who died on Oct. 31 from inhalation anthrax.

In contrast to the case of the two postal workers who died in Washington, no one faults the disease control centers for failing to prevent the deaths of Mrs. Lundgren and Ms. Nguyen. But the agency will certainly be judged by whether and how quickly it learns the source of their infections, because doing so could lead law enforcement to the criminals behind the anthrax attacks. And it will be judged as well by whether and how well it readies itself to deal with bioterrorism, which in the future could kill many more people.

"They have to get ready for the next, bigger hit," said Dr. Michael T. Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota. "It's not just what we did. It's what are we going to do."

The C.D.C., a branch of the federal Department of Health and Human Services, has long been asked to do too much with too little. Its buildings date back to World War II and are crumbling. Expensive equipment is stored in hallways and draped with plastic sheeting to protect it from rain dripping from the ceiling. In the early days of the anthrax outbreak, a power failure shut down the centers' laboratories overnight, just as technicians were trying to confirm a suspected anthrax infection in an employee of NBC News.

Based in Atlanta, the agency and its leaders are unaccustomed to the rough and tumble of Washington politics. They operate out of view of lawmakers and the public. Until this month, when President Bush toured the buildings, no United States president had visited the disease control centers while in office. Most Americans rarely give the centers a second thought, until an outbreak of disease ?AIDS, West Nile virus and now anthrax ?forces them to think about the importance of public health.

Critics say leaders at the disease control centers have, until recently, expressed little interest in preparing for bioterrorism, viewing it as a theoretical threat that distracted from their work of fighting real diseases.

As concern mounted about bioterrorism in the mid-1990's, the agency did not seek any money to prepare for the threat. But in 1999, the centers started an antibioterrorism program at the direction of Congress, which appropriated $122 million for it, a small fraction of the agency's $2.6 billion overall annual budget at the time. The amount has since increased to $181 million out of a yearly budget of $3.9 billion.

Officials used the money to build a network of 81 public health laboratories that can test for biological agents, including anthrax, as well as to improve communications between state and local health departments and the centers, and to develop a National Pharmaceutical Stockpile, a cache of medicines and supplies to be used in emergencies. The government drew on the stockpile for the first time after the Sept. 11 attacks, when drugs and supplies were shipped to New York City, and has since used it to provide drugs for people exposed to anthrax.

As a result of the antibioterrorism program, Dr. Koplan said, the agency now has a "world-class anthrax laboratory" and a unit of anthrax experts. But despite these improvements, the recent anthrax outbreak, which is a limited germ attack by any measure, has stretched the C.D.C. thin.

Its laboratory technicians are working overtime, even sleeping in their laboratories, and epidemiologists are being pulled from their regular jobs to join in the investigation. Few have had experience with anthrax. Until last month, when a Florida man came down with the inhalation form of the disease, only 18 cases of inhalation anthrax had been seen in this country in the last century.

So the agency found itself learning as it went. As Tommy G. Thompson, the secretary of health and human services, told the House of Representatives this month, "The response to anthrax is an evolving science." He said it was a testament to the centers "that people with inhalation anthrax are walking out of the hospital."

Yet that accomplishment may be overshadowed by the agency's decision not to treat postal workers in Washington. It was a decision based on the mistaken ?and easily testable ?assumption that anthrax could not escape a sealed envelope. And the agency has made other missteps. For instance, it was not until a few weeks ago, and then only at the urging of advisers to Mr. Thompson, that officials of the centers consulted with the retired Army scientists who developed anthrax as a weapon in the days before the United States abandoned its biological warfare program in 1972.

That kind of consultation might not have saved lives, experts say, but it might have given officials at the disease control centers a better understanding of how anthrax spores could float through the air. And it might have helped guide the centers as the agency made scientific decisions about which people, and what buildings, to test. For instance, officials used nasal swabs early in the outbreak to test people for exposure to anthrax. But they later learned those tests were largely useless.

Agency officials, and in particular Dr. Koplan, have also been criticized for being inaccessible to reporters and medical professionals in the early days of the anthrax attack, creating confusion among the public and, more important, doctors.

That problem has since been corrected. On Wednesday, the day Mrs. Lundgren died, a news conference to discuss her case featured the nation's foremost health officials: Mr. Thompson and Dr. Koplan, as well as Dr. D. A. Henderson, who heads a new bioterrorism preparedness office, and Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases.

"Could they have done better?" said Tom Milne, executive director of the National Association of County and City Health Officials, a group that has been critical of the disease control agency in the past. "Probably. Did they blow it? Absolutely not."

But if there are future anthrax attacks, Mr. Milne said, "if we don't do better, some heads ought to roll."

Public health people tend to tally their successes based on a calculus of lives saved versus lives lost, and on this score, said Dr. Scott Lillibridge, a centers' expert on bioterrorism, the agency's performance has been "about as good as you can get in a crisis environment." Those saved include people on Capitol Hill, who were exposed to a very potent form of anthrax when a tainted letter was opened in the office of Senator Tom Daschle, the Senate majority leader, and the postal employees who were treated aggressively after the first two died.

But as Dr. Osterholm, of the University of Minnesota, said: "You never really know in public health how many lives you saved. You always know how many you lost."