A Brief History Of: Flu Pandemics

A few days of fever, chills and generally feeling rotten: that's a typical case of the flu. But several times a century, flu viruses mutate so radically that they can trigger a pandemic--as health experts fear could happen with swine flu. Influenza may go all the way back to the dawn of medicine; a similar illness was first described by Hippocrates, in Greece in 412 B.C. In 1485, a flulike "sweating sickness" swept across Britain, leaving many dead--and treatments of the time, including the bleeding of patients, didn't help.

The latest pandemics, in 1957 and 1968, were mild, with global death tolls of about 2 million and 1 million, respectively. But doctors live in fear of a killer like the 1918 Spanish flu, which caused up to 100 million deaths. Undertakers were so overwhelmed that corpses were left inside homes for days. Cities passed laws requiring citizens to wear masks in public places, but the virus defeated that barrier; little stemmed the spread of the disease. From 1917 to 1918, average life expectancy in the U.S. dropped an amazing 12 years. Cruelly, the 1918 virus was particularly lethal in young and healthy people, who are usually more resistant to flu. The disease seemed to trigger a massive overreaction of victims' immune systems; when autopsies were performed on flu victims, lungs were found to be blue and sodden. They had died by drowning.

The Spanish-flu pandemic ended only when the virus had infected so many people that it burned itself out. Today, doctors have better tools--antivirals and respirators--that would cut the potential death toll. But influenza is unpredictable. "There's no standard picture for how this develops," says Keiji Fukuda, a top World Health Organization official. We can prepare, but in the end, we're at the mercy of a virus.