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ortunity that they haveenthusiastically seized。
in 1952； penicillin was fully effective against all strains of staphylococcus bacteria； to suchan extent that by the early 1960s the u。s。 surgeon general； william stewart； felt confidentenough to declare： “the time has e to close the book on infectious diseases。 we havebasically wiped out infection in the united states。” even as he spoke； however； some 90percent of those strains were in the process of developing immunity to penicillin。 soon one ofthese new strains； called methicillin…resistant staphylococcus aureus； began to show up inhospitals。 only one type of antibiotic； vanycin； remained effective against it； but in 1997a hospital in tokyo reported the appearance of a strain that could resist even that。 withinmonths it had spread to six other japanese hospitals。 all over； the microbes are beginning towin the war again： in u。s。 hospitals alone； some fourteen thousand people a year die frominfections they pick up there。 as james surowiecki has noted； given a choice betweendeveloping antibiotics that people will take every day for two weeks or antidepressants thatpeople will take every day forever； drug panies not surprisingly opt for the latter。
although a few antibiotics have been toughened up a bit； the pharmaceutical industry hasn’tgiven us an entirely new antibiotic since the 1970s。
our carelessness is all the more alarming since the discovery that many other ailments maybe bacterial in origin。 the process of discovery began in 1983 when barry marshall； a doctorin perth； western australia； found that many stomach cancers and most stomach ulcers arecaused by a bacterium called helicobacter pylori。 even though his findings were easily tested；the notion was so radical that more than a decade would pass before they were generallyaccepted。 america’s national institutes of health； for instance； didn’t officially endorse theidea until 1994。 “hundreds； even thousands of people must have died from ulcers whowouldn’t have；” marshall told a reporter from forbes in 1999。
since then further research has shown that there is or may well be a bacterial ponent inall kinds of other disorders—heart disease； asthma； arthritis； multiple sclerosis； several typesof mental disorders； many cancers； even； it has been suggested （inscience no less）； obesity。
the day may not be far off when we desperately require an effective antibiotic and haven’tgot one to call on。
it may e as a slight fort to know that bacteria can themselves get sick。 they aresometimes infected by bacteriophages （or simply phages）； a type of virus。 a virus is a strangeand unlovely entity—“a piece of nucleic acid surrounded by bad news” in the memorablephrase of the nobel laureate peter medawar。 smaller and simpler than bacteria； viruses aren’tthemselves alive。 in isolation they are inert and harmless。 but introduce them into a suitablehost and they burst into busyness—into life。 about five thousand types of virus are known；and between them they afflict us with many hundreds of diseases； ranging from the flu andmon cold to those that are most invidious to human well…being： smallpox； rabies； yellowfever； ebola； polio； and the human immunodeficiency virus； the source of aids。
viruses prosper by hijacking the genetic material of a living cell and using it to producemore virus。 they reproduce in a fanatical manner； then burst out in search of more cells toinvade。 not being living organisms themselves； they can afford to be very simple。 many；including hiv； have ten genes or fewer； whereas even the simplest bacteria require severalthousand。 they are also very tiny； much too small to be seen with a conventional microscope。
it wasn’t until 1943 and the invention of the electron microscope that science got its first lookat them。 but they can do immense damage。 smallpox in the twentieth century alone killed anestimated 300 million people。
they also have an unnerving capacity to burst upon the world in some new and startlingform and then to vanish again as quickly as they came。 in 1916； in one such case； people ineurope and america began to e down with a strange sleeping sickness； which becameknown as encephalitis lethargica。 victims would go to sleep and not wake up。 they could beroused without great difficulty to take food or go to the lavatory； and would answer questionssensibly—they knew who and where they were—though their manner was always apathetic。
however； the moment they were permitted to rest； they would sink at once back intodeepest slumber and remain in that state for as long as they were left。 some went on in thismanner for months before dying。 a very few survived and regained consciousness but nottheir former liveliness。 they existed in a state of profound apathy； “like extinct volcanoes；” inthe words of one doctor。 in ten years the disease killed some five million people and thenquietly went away。 it didn’t get much lasting attention because in the meantime an even worseepidemic—indeed； the worst in history—swept across the world。
it is sometimes called the great swine flu epidemic and sometimes the great spanish fluepidemic； but in either case it was ferocious。 world war i killed twenty…one million people infour years； swine flu did the same in its first four months。 almost 80 percent of americancasualties in the first world war came not from enemy fire； but from flu。 in some units themortality rate was as high as 80 percent。
swine flu arose as a normal； nonlethal flu in the spring of 1918； but somehow over thefollowing months—no one knows how or where—it mutated into something more severe。 afifth of victims suffered only mild symptoms； but the rest became gravely ill and often died。
some succumbed within hours； others held on for a few days。
in the united states； the first deaths were recorded among sailors in boston in late august1918； but the epidemic quickly spread to all parts of the country。 schools closed； publicentertainments were shut down； people everywhere wore masks。 it did little good。 betweenthe autumn of 1918 and spring of the following year； 548；452 people died of the flu inamerica。 the toll in britain was 220；000； with similar numbers dead in f