BAR HARBOR – It’s a long way from the breezy, blue freshness of a September afternoon on Frenchman Bay to the filth and wreckage of the Gulf Coast in the aftermath of Hurricane Katrina. But physicians attending the annual meeting of the Maine Medical Association here this weekend were asked to consider the potential for the same degree of chaos, disease and fear erupting in Maine, if the state were affected by the public health catastrophe many officials have predicted for years – the outbreak and worldwide spread of a lethal human influenza virus.

This is not the annual “flu season” illness, stressed State Epidemiologist Dr. Kathleen Gensheimer. Though the yearly flu bug predictably infects up to 20 percent of Americans, hospitalizes hundreds of thousands and kills an average of 36,000 each winter, it is largely preventable with an annual vaccine, either injected in a large muscle or squirted in the nostrils. Healthy adults who forgo the flu vaccine may get miserably ill for a week or more – and may contribute to a community outbreak that dangerously sickens more vulnerable individuals – but they rarely die.

By contrast, Gensheimer told conference attendees at the Harborside Hotel on Friday, the as-yet-unknown virus feared by public health officials across the globe will be a much more virulent strain of influenza, against which humans have little or no resistance and which is passed quickly and easily from one human host to another. Facilitated by today’s global economy and rapid transportation systems, the virus could travel around the globe in a matter of days before its lethal symptoms are recognized.

Similar pandemic outbreaks wreaked havoc in the past century, she noted. Spanish influenza – thought to have originated at a Kansas military base in 1918 – caused between 25 million and 50 million deaths around the world, and 500,000 deaths in the United States. In 1957, Asian flu killed about a million people, 70,000 of them Americans. And Hong Kong flu was responsible for the deaths of more than a million globally and about 34,000 in the United States.

Health officials estimate that even with advanced medicines and effective planning, the coming flu pandemic will kill between 90,000 and 200,000 Americans, including 900 Mainers.

A likely point of origin, closely watched by scientists and health officials, is Southeast Asia, where flocks of poultry and migratory birds have been diagnosed with an especially virulent strain of avian influenza. Since 1997, the microbe has crossed out of the bird population to infect 112 humans in Cambodia, Thailand, Indonesia and Vietnam. More than half of the infected individuals, most of them relatively healthy younger people, have died. There are just a few cases in which it appears the disease has actually passed from one person to another.

“Is this just the tip of the iceberg?” Gensheimer asked her audience. “There could be much more human-to-human infection going on that we just don’t know about yet.” Wherever the new viral strain comes from, and whenever it blossoms fully, Gensheimer said, the impact of the pandemic influenza will be huge and devastating. It will be up to state and local officials and health providers to provide leadership in managing a desperate population of sick and frightened people.

The state, in cooperation with the World Health Organization and the U.S. Department of Health and Human Services, has developed a preliminary plan for detecting and responding to a global outbreak of influenza. The plan, still in draft stage, can be seen on the Web site of the Bureau of Health, www.mainepublichealth.org.

The pandemic flu plan address many of the issues that appear to have contributed to the tragedy of Hurricane Katrina, and reflects its practical application to a variety of emergency situations. It outlines roles and responsibilities for key government offices before, during and after the pandemic strikes. It sets in place a method for identifying clusters of cases in Maine, a strategy for distributing scarce supplies of effective vaccines and other medications as they become available, and a model for maintaining essential public services such as water supplies, electricity, transportation and communications systems.

It also identifies the state of Maine’s legal authority to quarantine sick individuals against their will or move them to designated facilities to minimize the spread of the virus – a thorny legal issue in the Gulf Coast area, where residents are being forced to leave their homes.

After Dr. Gensheimer’s presentation, a panel of public health professionals fielded physicians’ questions about access to antibiotics and other medications, legal liability during a declared health emergency, the priority of vaccinating front-line health care workers before the general public and other issues.