The global spread of concern over a deadly strain of influenza has local public health experts questioning how the area would respond if an outbreak happened here.

Avian influenza, a virus that experts worry could mutate into a form transmittable between humans, has stirred frightened warnings from the World Health Organization, which said the disease could cause as many as 50 million deaths in the direst scenario.

On Wednesday, Boston health officials conducted their second exercise in as many weeks designed to gauge the region's state of preparation to confront a disease that has some invoking the 1918 "Spanish flu" epidemic that killed as many as 50 million.

Thus far, the disease has claimed fewer than 100 lives in Asia, where it has been spread between fowl, but last weekend a strain of the bird flu was found in Romania, sending Europeans scurrying to stockpile vaccines.

Last week, the U.S. Senate approved by unanimous vote a defense spending bill that included $3.9 billion to fight avian flu, largely by developing vaccines.

If the virus transforms into one that humans can pass between each other, and arrives in the United States, policy makers have said the nation is not ready to inoculate more than 5 percent of the people who will need it.

Experts warned against alarmist speculations that a place like Dorchester - a densely populated urban area with a high, mobile immigrant population - might be hit early and hard.

"If avian influenza is going to come into the United States, there's no way of knowing where it's going to come first," said Dr. Anita Barry, director of the Boston Public Health Commission's Communicable Disease Control department.

The two recent conventions of local health care leaders keyed on scenarios of pandemic influenza. Last week, officials met in Brookline and discussed how the region would react if an outbreak hit the Boston area and the governor ordered schools closed, a likely development to prevent the disease from spreading, Barry said.

On Wednesday, the day the Reporter went to press, officials were planning to meet again, this time focusing on how hospitals would coordinate a response to an outbreak of pandemic avian influenza, said Tom Lyons, a spokesman for the BPHC.

The "table top" exercises allow representatives from a variety of health care stakeholders to conduct drills for "very bad situations," Barry said. With the sudden appearance of avian influenza in the public eye, as it has crept onto front pages and airwaves during the past few weeks, a sense of urgency has taken hold.

"I think one of the things that came up from the drill was the importance of dealing with these things on a regional basis, not only on a publicity basis but also on a policy basis," Lyons said.

As policy makers worldwide struggle with the scope of the threat, participants in last week's "table top" said several themes have begun to emerge. First, said Barry, is that people should take the usual precautions as flu season arrives, washing hands and getting vaccinated against the traditional flu and against pneumonia, which is often the direct cause of death in flu fatalities.

"If they should've gotten a pneumonia shot, if they're a candidate, do it now," Barry said.

Another step is planning for an outbreak, said Dr. Susan Foster, an international health professor in the Boston University School of Public Health. People should consider what to do if schools are closed or if as many as a third of workers are forced to stay home. Family members and neighbors of elderly people who are forced to stay home should plan for ways of caring for them, Foster said.

Last week, U.S. Senator Edward M. Kennedy sponsored a bill calling for increased federal attentiveness to the threat of an outbreak. The Pandemic Preparedness and Response Act calls for the creation of a White House position and improving the country's public health infrastructure. The bill proposes stronger surveillance of potential strains and the "procurement of antivirals to cover a minimum of 50 percent of the population," according to a summary provided by Kennedy's office.

Who will be first in line for those vaccines is another question, said a Kennedy aide, speaking on background, part of a policy formulation that Kennedy has pressed for since January of last year.

"A year and a half later, there is still no final plan," Kennedy said during his introduction of the measure last week, according to a prepared text provided by his office. "We should be implementing a flu plan now - not waiting to read it for the first time."

Foster said that a developing "consensus" for which demographic is prioritized has placed medical and first response workers high on the list. That, Foster said, represents a fundamental shift from the traditional priorities, which generally place elderly people first.

The strain of avian flu - known as H5N1 - has a mortality rate of 50 percent once it has landed among human populations, experts say. Chickens, ducks, turkeys, and geese carry the disease, with most of the fatalities taking place in people who work on poultry farms.

Currently, all the human mortalities have been in Vietnam, Thailand, Indonesia, and Cambodia.

That East Asian locus worried Bill Walczak, president of the Codman Square Community Health Center, when he was in Vietnam last January. Walczak said he encountered a number of Americans visiting from the Greater Boston area.

"I realized at that point that if the avian flu hits in what's likely to be in Vietnam or Hong Kong or somewhere around there … probably 24 hours later it'll be in Dorchester," Walczak said. "That's a far more fearful thing for me, thinking about how quickly the world moves today, and about how quickly a devastating pandemic thing like avian flu gets around the world … But that's not just here to Vietnam. That's everywhere. People travel all the time now, and when you compare it to 1918, it's a different world."

Information from the Associated Press was used in this report.