The new H5N1 has shown its teeth in New York after weeks of excruciating false alarms. The mutated bird flu killed a yet-to-be-identified bus driver and put a dozen people in rotten condition into hospitals all over town.

My neighbors aren’t convinced. New Yorkers do far more damage to each other every night and no one fusses about it. I can already hear some lusty students from Happy Hour U marching down Avenue B to the rhythm of shrieking girls. The guy downstairs is bawling out his boyfriend’s sister. What will it take for a mere microbe to impress these busy, urbane souls?

NO BOWL OF RASPBERRIES: THE H5N1 VIRUSThe disease-of-the-week thing is old. Since 9/11 we’ve seen (more like, heard about) West Nile virus, SARS, the original, dreaded H5N1 bird flu, untreatable TBX tuberculosis, MRSA, and swine flu. Someone even dusted midtown Manhattan with government-issue anthrax. So why should Gothamites care about some remix of a flopped disease that scared everyone silly in 2006 and then flew off to plague (mostly) Egyptians and Indonesians while the pigs plagued us?

Because this one’s a Category 5 hurricane, folks. Welcome to the Ninth Ward.

Novel H5N1 has everything the Great Pandemic Flu of 1918 had, and more. It’s transmitting more easily every day and it looks to be able to kill a greater percentage of people more horribly than any influenza ever recorded. Far more than anyone predicted swine flu would kill.

The remarkable strain that surfaced in the U.S. and Mexico in 2009 with genes from birds, pigs, and humans spread more fear than fatality before we gained immunity to it. Nowhere was the toll as high as the media said it might be—when it wasn’t mocking its own warnings—but flu mortality is tough to quantify. It's clear that a lot of young people who would never have succumbed to seasonal flu were killed, but influenza always invites other conditions to take the final credit.

It’s easy to forget how scary swine flu was before it turned into another noisy dud. People in poorer countries suffered much more than we did, though I knew someone who died from it. I miss her. Only fools dismiss A/H1N1 swine flu as microbial Y2K.

Still, who wants another one? How can we even contemplate such a thing—let alone something far worse? Isn’t there supposed to be a long gap between pandemics?

Sometimes.

The world experienced huge flu outbreaks in 1946-47, when the vaccine utterly failed, and 1951, when Liverpool’s weekly death toll was greater than during the 1918 pandemic. Then came the 1957 H2N3 Asian Flu pandemic. That’s a lot of virulence in what, 11 years?

Back when swine flu was exploring the earth in its first wave, flu blogger Scott McPherson speculated that H1N1 might be conducting its “farewell tour,” just the way those epidemics in 1946-7 and 1951 turned out to herald that strain’s collapse in 1957. He was right. This year, the H1N1 that’s been around in one form or another since it revived in 1977 has been melting away.

Swine Flu's Secret Punch

The problem is that swine flu left a memento. True to its nickname, it managed to get into Indonesia’s pig population. There it encountered H5N1, the incredibly nasty bird flu that loves to get into mammals but had been having a hard time getting humans to give it to each other.

Nature cares little for irony, so it's mere coincidence that a Muslim country hosted the porcine union that inspired the historic viral bonding. H1N1 gave up some vital genetic snippets—presumably through a process known as reassortment—and soon H5N1 was killing a lot more Indonesians. Then Vietnamese. While I don’t trust the numbers from China, the government is obviously trying to suppress a roaring panic in Guangdong. I’m still waiting for the new H5N1 to reach Egypt, where I fear it will land like sparks in a parched field. (Egypt has been dealing with H5N1 cases since 2006.)

In a month, this mutated avian flu has struck four continents, killed at least 500 people, and even shown signs of picking up immunity to Tamiflu—the primary antiviral medicine in the world’s flu arsenal. While H5N1 swiftly learns how to infect us, we’re learning that humanity drew the wrong lessons from swine flu.

Most people are stlll guzzling assurances that Novel A/H5N1 is not a threat. Even tonight, opinion makers argue that avian flu has lost its bite. Why, it used to kill two-thirds of its victims! Now it’s down to a few percent—mostly fools with underlying health conditions, or foreigners who don’t eat as well as we do. No worries. Let’s keep our financial markets on an even keel. Let the tourist industry weather the latest threat.

We’ve seen worse, right? There was no panic in the spring of ’09, when people traveling out of New York brought swine flu to scores of countries. I recall a party in Williamsburg at which I complimented the hostess on the creamy chocolate strawberry cake I was devouring. "I could hardly finish it because I'm just getting over the flu," she murmured. I gazed at the moist chunks of tasty textured fluff and opted not to stash her confection behind the punch bowl. So many yummy virions!

DIY, ASAP

This is no time to be smug. Sure, I sell personal protection gear on this site—and I can’t prove it makes much difference for non-health workers to wear professional-grade masks, goggles, and gloves—but I got into this line because I was scared. I wear the gear myself. I want to do something to fight this disease. I’ve known for years that a killer influenza pandemic is inevitable.

How could I be so sure? I wasn't alone. Pandemics have been raging since people gathered in cities that traded with one another. One of the remarkable features of a true pandemic is that the previously dominant flu strains (for us, it’s been H3N2 and H1N1 since a likely lab accident in 1977 revived H1N1) tend to give up the ghost when a new pandemic strain comes along. Suddenly—around the world—people are far more likely to catch the new strain. No one knows why, but the old subtypes bow out gracefully.

In April 2009, when swine flu broke out along the Mexican border, the seasonal flu strains were already subsiding. Americans looked forward to summer. But when Novel H1N1 turned up, the seasonal strains responded by reactivating intensely for a couple of weeks, as if to vanquish an intruder.

That told me swine flu was missing something—a kind of legitimacy—and that the other strains knew this. (If this sounds paranoid, be warned that I consider influenza a natural system that humans have yet to fathom, kind of like a social network teeming with invisible murderers.)

Guess what? This time, the seasonal strains have vanished—relatively early in our season. H5N1 is gathering force like a prince assuming the throne.

It’s time to admit that another pandemic has begun, whether or not we like the timing. (In detail, it's never what we expect: H1N1 swine flu defied conventional logic in many respects.)

Don’t look to the world’s various political and economic systems for help. Swine flu made experts and authorities look ridiculous after they’d spent years preparing for the bird flu that now threatens. Have you watched the World Health Organization wrestle all over again with the questions of whether and when to declare a top-level pandemic flu threat? The agency dithered for weeks over its conditions for swine flu—why not do it again? The countries whose voices count never want a pandemic. Who does?

By the time the threat is formally recognized, H5N1 will be upon us.

It’s already here, where I live. Coming soon to your ‘hood. Get ready.

And oh yeah, welcome to my blog. I haven’t ever done this before, so please be kind.

I invite you to visit the excellent flu bloggers and news sources I rely on. Most have been reporting and analyzing viral developments for many years. We’re fortunate to be entering this crisis with such seasoned commentators.

See you tomorrow.