Until such bold adventurers as Verrazano and Hudson penetrated its unpolluted waters, North America enjoyed extraordinary freedom from epidemics. In pre-Columbian times there had been no plague (Black Death), cholera, yellow fever, malaria, typhoid, tuberculosis, diphtheria or even measles.
The pioneer immigrants brought their foul European diseases with them. Aboard their ships, filthy water and human and animal wastes sloshed around in the bilges for a month or more. Men and women who were healthy when they left Europe were sick when they landed not only from malnutrition but also from infections picked up at sea. Some, such as smallpox, malaria and measles, proved effective biological-warfare weapons, ravaging the Indians, who had no immunity against them. But most of the disease-causing microbes of the Old World took readily to the fertile soil of the New World, and so did the insects and vermin that carry them. The result: for fully three centuries, North America was scourged by deadly epidemics.
By 1674, John Josselyn wrote of the Massachusetts settlements: "The Diseases that the English are afflicted with, are the same that they have in England, with some proper to New-England, griping of the belly (accompanied with Feaver and Ague) which turns to the bloudy-flux, a common disease in the Countrey, which together with the small pox hath carried away abundance of their children." This same Josselyn attributed to the Indians "the great pox" (syphilis), consumption of the lungs, the King's Evil (scrofula) and falling sicknessall of which happened to be imports from the Old World.
The U.S. enjoyed miraculously long immunity from the dreaded plague that used to sweep Europe. It was not until June 27, 1899, that the S.S. Nippon Maru reached San Francisco, carrying, among other things, eleven Japanese stowaways. Two were found drowned, and infected by the plague. Early in 1900 a Chinese immigrant, found dead, was also shown to have had plague. The resulting political furor was reminiscent of the Middle Ages, with the Governor of California insisting that there was no problem and federal authorities demanding stern measures for quarantine, isolation, disinfection and rat extermination. It took almost ten years of squabbling and litigation before all plague-carrying rats were destroyed and the disease suppressed. The last U.S. epidemic of classic bubonic plague struck Los Angeles in 1924, causing 30 deaths. But the wild rodents of the Western states also carry fleas that in turn carry plague bacilli. In 1975 there were 20 reported cases of this "sylvatic" plague.
The most savage of all epidemics in the world since the Black Death, and by far the most lethal in the history of the Americas, was the 1918-19 worldwide pandemic of influenza. Often called the Spanish flu because some of the earliest cases reported were in Spain, it actually erupted simultaneously in places as far apart as southern Russia and Greenland. Soldiers on the battle front suddenly keeled over. Policemen donned masks to direct traffic, and small children were similarly covered in their carriages.