In recent weeks, news of the latest outbreak of “bird flu” has gained currency in the mass media. Some suggest there is nothing to fear, while others warn that hundreds of millions may be in peril. The truth is that either scenario is possible – which is to say, the real issue is one of probabilities.

The avian viruses exist in nature mainly in bird populations, both wild and domestic. They are constantly mutating, or, in scientific terms, undergoing antigenic drift and shift. Some of these viral changes can infect other species; this includes mutating into a form that can be passed to and, potentially, among humans.

Most avian viruses are not transmissible to humans, and the few that are generally occur where large numbers of birds and humans live in close proximity and contact. Infection is more likely when the virus has mutated into a form that infects other mammals, such as pigs. Conditions favorable to such mutation did exist widely in the Western world but now are found to a much greater degree in Asia. This is particularly the case in China, which is why so many new influenza strains, like the one in question, H5N1 type A influenza, first surface there.

H5N1 has been a source of concern since it was first detected in 1997. If it mutates into a form that is highly transmissible among humans, rather than only from direct contact with infected animals, it could set off a pandemic. This is precisely what scientists now think caused the 1918 influenza (Spanish flu) pandemic. World War I accounted for some 16 million military and civilian deaths from 1914 to 1918, but in 1918 alone, there were more than 40 million deaths from influenza. The U.S. saw 600,000 flu deaths that year – roughly the same death toll of the entire Civil War.

Victor Vaughan, Surgeon General of the Army at the time, said in October, 1918, “If the epidemic continues its mathematical rate of acceleration, civilization could easily disappear from the face of the earth within a few weeks.” Fortunately, it had run its course in less than a year, having killed off most of its hosts. Notably, the pandemic of 1918 infected mostly those aged 20-40 and spared the young and elderly. The mortality rate was 40 percent for those infected.

American scientists have just revived an active specimen of the 1918 influenza strain for research purposes (our global adversaries have taken note). Rutgers bacteriologist Richard Ebright hopes that this strain does not find its way into the hands of a “disgruntled, disturbed laboratory employee,” as may be the case with the military strain of anthrax that found its way into mail circulation shortly after 9/11.

Research on the 1918 influenza genome suggests the H5N1 shares some virulence factors with the 1918 strain, but it is clearly differentiated because the H5N1 infectious rate has remained contained for eight years – accounting for fewer than 100 deaths in that time period.

Johns Hopkins University’s Donald Burke, MD, says, “We’re seeing lots of these cross-species interactions now in Southeast Asia. I call it ‘viral chatter’ because it’s like the terrorist ‘chatter’ that goes on over the airwaves and suggests something serious is just around the corner.”

Indeed, new studies from the Armed Forces Institute of Pathology, the Centers for Disease Control and Prevention and Mount Sinai School of Medicine conclude that real trouble may really be just around the corner. Modeling of the H5N1 infectious rate should it become transmissible among humans indicates that the loss of life could be in the hundreds of millions, particularly in Third World populations.

Since 9/11, our nation has undertaken massive civilian and military planning and preparation to enhance our response and recovery capabilities in the event of a catastrophic attack – including an attack utilizing biological WMD. These efforts have collateral benefits for a pandemic of natural origin, as the response and recovery protocols are very similar. But one is left to wonder whether a national response, which must be massive and swift, would be more effective than, say, the national response to Hurricane Katrina?

The disconcerting answer is, maybe.

President George Bush, himself recovering from substantial criticism (much of it unwarranted) that the central government did a miserable job responding to Katrina, is staying well ahead of the H5N1 potential pandemic curve. He should, given that a pandemic, by comparison, would make Katrina’s wrath seem trivial.

Noting that the response and recovery efforts to Hurricane Katrina congealed only after military leaders were deployed to the region, Mr. Bush said this week, “If we had an outbreak somewhere in the United States, do we not then quarantine that part of the country, and how do you then enforce a quarantine? … And who best to be able to effect a quarantine? One option is the use of a military that’s able to plan and move.”

Of course, there are some constitutional questions regarding the use of military forces in domestic civilian operations. President Bush signed an executive order that, in effect, bypasses the Posse Comitatus Act in the event of a national crisis, though it comports with the U.S. Constitution’s Article IV, Section 4 and the Tenth Amendment. (See The Patriot’s commentary on new momentum to rescind the Posse Comitatus Act, below.) However, if a pandemic does reach North America, don’t expect an outcry about military occupation and quarantine.

John Barry, distinguished visiting scholar at Tulane University’s Center for Bioenvironmental Research and author of The Great Influenza: The Epic Story of the Deadliest Plague in History, told researchers this month that, in addition to the mortality outcome of the 1918 pandemic, one of its most alarming features was that it ripped apart the basic humanitarian fabric that binds civil society.

In other words, military deployment will be critical to the success of any response and recovery effort, and continuity of government and commerce.

On average, pandemics have occurred in 40- to 50-year intervals. The Institute of Medicine of the National Academy of Sciences reports, “[A]nother influenza pandemic is possibly inevitable and even overdue.”

So, how vulnerable are we now? We are back to the probabilities question. While a pandemic is not likely, we are overdue. Right now, H5N1 is akin to a tropical depression far off in the Atlantic – one with little likelihood of making landfall in the U.S. On the other hand, it could well become a category-five storm that threatens the entire nation.

If H5N1 or a future influenza strain does become highly transmissible among humans, we have far better epidemiological tools to track infectious outbreaks. We also have anti-flu drugs and can develop specific vaccines more quickly. Further, we have isolation protocols and can utilize resources appropriated for bioterrorism response and recovery.

Though it has been suggested that 100 million doses of H5N1 vaccine be stockpiled, this would be both exceedingly expensive and possibly ineffective, depending on the form the virus takes if it becomes highly transmissible. Of course, many thought that improving the levees of New Orleans would have been exceedingly expensive.

There is the theoretical possibility that an outbreak could become pandemic before we are able to contain it, even with all of our improved tools for recognition and response. That possibility is far higher today than in 1918 because population centers are far more dense, and one infected individual can travel halfway around the world in a day – as visitors from Asia and Africa regularly do. That visitor, landing in a major air-traffic hub in the U.S., could pass the infection to hundreds of people who are traveling to other urban centers across the U.S. Within a matter of hours, the nation could have pockets of infected citizens coast to coast.

All this having been said, the most effective measure – the bedrock foundation of survival – is individual preparedness. Being prepared is not difficult. The primary means of protection against pandemic infection is sheltering in place. To learn more about preparing your family to shelter in place, link to this Recommended Action Plan for Mitigating the Consequences of Natural or Attack Catastrophe on Your Family and Community. As for when to implement your family preparedness plan, in the words of Benjamin Franklin, “Have you something to do to-morrow; do it to-day.”