In this 1918 photograph, influenza victims crowd into an emergency hospital at Camp Funston, a subdivision of Fort Riley in Kansas. The flu, which is believed to have originated in Kansas, killed millions of people worldwide.

The calendar says 2009, but our fears say it is 1918.

The front page tells us about Mexico, and a new strain of influenza that has killed more than a dozen people there and spread to the United States and Europe and Asia.

But our dire imaginations take us back to another contagion in another century. Victims sometimes died within hours, blood coursing from noses and mouths; coffins piled high on city streets. Worldwide, multitudes succumbed — 40 million, 100 million, no one knows for sure.

Could it all be unfolding again?

It’s unlikely. The Spanish flu epidemic was, in the words of writer Lynette Iezzoni, “the most catastrophic season of death in human history.” The cause was a new virus with a special talent for slaughter; scientists literally did not know what they were dealing with.

Mass movements of men to fight in World War I helped spread the disease, while government officials — eager to keep wartime morale high, and panic low — downplayed the disaster.

We live in a very different time. No one knows whether the new swine flu will develop into a major killer, but viruses are better understood. U.S. health officials say the new strain’s genetic makeup doesn’t show specific traits that showed up in 1918. Communications are quicker and treatments like Tamiflu are available. And governments are taking the new swine flu very seriously, and have planned for the best, the worst and everything in between.

But we move around a lot more than our grandparents and great-grandparents did, taking planes to distant cities and our cars to the neighborhood Starbucks. Viruses tag along.

Even though our health-care system is much more sophisticated, it too could be overwhelmed by even a milder flu epidemic, authorities say. And while modern medicine can do miracles, it cannot conquer nature entirely.

“No matter how well we prepare,” says Dr. William Schaffner, chairman of the Department of Preventive Medicine at Vanderbilt University, “there will be illness, there will be death.”

‘Nothing to worry about’

It started at Fort Riley, Kan., on March 11, 1918, when Army Pvt. Albert Gitchell reported to the camp hospital with a fever, sore throat and headache.

“Just the flu. Nothing to worry about,” writes Iezzoni in her book, “Influenza 1918: The Worst Epidemic in American History.” “A minute later, however, another sick soldier showed up. Then another. By noon, the baffled hospital staff had 107 cases on their hands. By week’s end: 522. In the next month, well over a thousand.”

All together, 48 died in that outbreak. The flu spread to other army camps, to a Detroit auto plant, to New York City and Minneapolis and some other cities. The death totals were not especially alarming, but some authorities noted something puzzling: The victims were more often young, healthy adults, the people who are normally least likely to die of the flu.

For most health authorities of the time, the flu was an afterthought. Years later, when Brigitte Charaus was researching the 1918 epidemic in Milwaukee, she found that flu fatalities were not normally recorded.

“Here I am, looking at the year of one of the most significant disease events in human history, and it’s a penciled-in number,” says Charaus, now a professor of history at Santa Clara University. “Obviously, it caught everyone by surprise.”

The illness faded in the United States, but spread around the world. It came to be called the Spanish influenza — perhaps because the Spaniards, who were not at war, did not censor reports of the disease’s toll.

Then, in August, the flu suddenly became a hard-core killer. The mutation, it appears, occurred in Brest, France. Boston was the first American city to suffer.

The victims coughed and suffered high fevers and bloody discharges. Pneumonia often followed the flu, and victims turned purple, drowning in their own fluids.

Soon, corpses were literally piling up in the cities. In New Haven, Conn., 6-year-old John Deleno broke his nose climbing on the caskets outside a mortuary, not realizing that there were bodies inside. In West Philadelphia, Donohue’s funeral home hired men to guard coffins that were in short supply — they were being stolen.

Philadelphia was the hardest-hit city in America; on a single day in October, 711 people died there. Authorities had assured the populace that there was no reason to fear the flu and, like others around the country, Philadelphians had jammed War Bond and Liberty Loan rallies, had gathered in large groups to register for the draft.

It was, writes historian Alfred Crosby, “a pattern of complete insanity.”

People were advised to wear masks (mostly useless). They were inoculated with bacteria (entirely useless). They were told that cigarettes would kill the germs. Rumors circulated that Bayer aspirin was being used by Germany to spread the flu.

Franklin D. Roosevelt, then assistant secretary of the Navy, caught the flu. So did Mary McCarthy and Katherine Anne Porter, who would grow up to be writers, Amelia Earhart and Gen. John “Black Jack” Pershing. And President Woodrow Wilson, who contracted the disease during the postwar conference at Versailles and was unable to argue for his war aims forcefully.

The worst of it ended, coincidentally, with the end of the war in November, though there were flare-ups around the world through the next spring. In the end, an estimated 675,000 Americans died, including about 57,000 soldiers — 3,500 more than died on World War I battlefields. In a population of 103 million, nearly a quarter caught the flu.

But others suffered even more. In India, alone, as many as 20 million people died.