s federal health officials analyze information about patients with inhalation anthrax, they are urging doctors to look aggressively for the potentially lethal condition even when they see postal workers in the Washington area with mild, vague symptoms.

The reason is that people with inhalation anthrax may survive if their cases are diagnosed promptly and they receive antibiotics and any needed respiratory care in the early stages of the infection.

Officials are recommending a 10- day course of the powerful antibiotic Cipro for thousands of postal workers around Washington while epidemiologists figure out who among them were most likely to have been infected. Those at risk would receive a 60-day course of Cipro or other equally effective antibiotics.
Dr. Anne Schuchat, an epidemiologist at the Centers for Disease Control and Prevention in Atlanta, said in an interview that the four Washington postal workers who came down with inhaled anthrax — two of whom died on Monday — experienced initial symptoms of fever, headache, chills, sweating and malaise for a couple of days — in short, the symptoms of flu.

Some patients experienced a mild cough and a feeling of heaviness in the chest, resembling respiratory flu. Others had nausea, vomiting and diarrhea, more suggestive of stomach flu, before developing the more serious respiratory symptoms.

The symptoms were often so mild and nonspecific that under ordinary circumstances they would not impress a patient or a doctor as warning sign of something more serious. So the symptoms might be dismissed as those from an ailment that would go away on its own in a day or so.

But Dr. Schuchat said, "In the Washington, D.C., area, very nonspecific, unimpressive symptoms in a postal worker should be taken extremely seriously." She added that experience so far has shown that a patient whose symptoms "would not cause an excess amount of concern" can quickly become critically ill.

"It would not be extreme," she said, "to hospitalize a febrile postal worker with a not very impressive illness, just to initiate treatment" and then monitor the patient's course.

The recommendations apply only to areas where inhaled anthrax has been diagnosed or is strongly suspected. Elsewhere, flulike symptoms "would not make us think of anthrax," said Dr. Schuchat, who is an expert in the epidemiology of respiratory illness.

Yet the diagnosis can be a major challenge for even the most astute doctors.

Anthrax bacilli that reach the small air sacs of the lung are carried by scavenger cells to the mediastinum, a space between the back of the lungs and the spine, where they cause lymph nodes to swell. Those swollen nodes are a characteristic finding in inhalation anthrax.

Because chest X-rays of postal workers in the early stage of inhalation anthrax have shown the swollen lymph nodes, Dr. Schuchat said, her agency is urging doctors to consider taking X-rays and carefully examining them for the abnormality. "The mediastinal X-ray findings were immediate clues that something unusual was going on," she said, and led to more extensive testing that detected anthrax in the patients.

Doctors were also urged to perform rapid tests that can detect infections like those caused by streptococcal bacteria and influenza virus.

In recent years, to save money under managed care, many doctors have reduced the number of tests they order and simply use their judgment about diagnosis and treatment. But now, doctors may have to order more tests more often, Dr. Schuchat said, and "there may be some comfort" in knowing that the patient has something other than anthrax.

Another recommendation was to culture the blood of patients to identify Bacillus anthracis in the early stages of illness. The bacillus often grows rapidly in a laboratory culture and in one patient, the bacilli grew in a laboratory culture in 15 hours.

In another patient, the blood was so full of the bacilli that they could be seen under a microscope with the help of chemical dyes. The test, which can be done in a few minutes, is known as a Gram stain, after Dr. Hans Gram, the Dane who developed it. B. anthracis appears as a Gram- positive rod, so the test can alert doctors to the diagnosis quickly if the bacteria are present.

Another standard test is to measure the number of white cells in the blood. They often rise in a bacterial infection. But some patients had a normal white count in the early stages of illness, Dr. Schuchat said.

Doctors are supposed to ask patients where they work and what they do, but the questions often go unasked, particularly when doctors are pressed for time. Now, Dr. Schuchat said, the questions are essential, even in a busy emergency room, because occupation is a crucial factor in the anthrax outbreak.

Still another test involves taking nasal swabs from people who may have been exposed. The test is valuable for two reasons. Swabs can detect spores trapped by hairs inside the nose, so scientists can tell whether an area has been contaminated, just as they can by swabbing desktops and floors. And swabs can help epidemiologists determine whether an environmental exposure might have been through a mist, or aerosol.

But Centers for Disease Control officials warn that for all their epidemiological value, nasal swabs have little or no value in diagnosing anthrax in patients.

"The nasal swab is not a test in Washington, D.C. — or anyplace else — that is useful on a case-by-case basis for identifying whether someone has been exposed" to anthrax, said Dr. David W. Fleming, deputy director of the disease control centers. Dr. Fleming added that studies in monkeys suggested that anthrax spores disappeared quickly after appearing in the nose.

"We do not know for sure whether that same thing is true in humans," he said, "but we are concerned that someone could mistakenly believe that a negative nasal swab would mean that they are not at risk."

Moreover, scientists suspect that a swab taken today would not detect spores in someone exposed to spores a few days earlier.

With widespread publicity about the use of nasal swabs in the investigation, many people have gone to their doctors to demand such a test to determine if they are infected. But Dr. Fleming said this was turning an epidemiological tool into a clinical test, and added that it "is wrong."

Anthrax spores are found in the soil in many parts of the country. Experts interviewed said they knew of no survey that has been conducted to determine how often anthrax spores are found among healthy people who have had no known exposure to the spores in this country.

But Dr. Fleming said that eventually scientists should gain a better understanding of the problem by studying the information collected from the swabs that have been collected for epidemiologic purposes in the current anthrax outbreak.