Madeleine Johnson: Why the Pilgrims Thrived at Plymouth

Madeleine Johnson is a science writer and former neuroscientist.

Rat urine. As we feast on succulent turkey, moist stuffing, and glistening cranberry sauce this Thanksgiving, the furthest thing from our minds is probably rat urine.

Yet it’s quite possible that America as we know it would not exist without rat urine and leptospirosis, the disease it spreads. The disease conveniently cleared coastal New England of Native Americans just prior to the Pilgrims’ arrival and later killed the helpful Squanto. It still lurks among us, underdiagnosed, an emerging menace.

In the winter of 1620, the Mayflower happened to dock at an abandoned village. It had been known in the local Wampanoag language as Patuxet. Pilgrims rejoiced; the land "hath been planted with corn three or four years ago, and there is a very sweet brook runs under the hillside." In fact, the French explorer Samuel de Champlain had observed what would become Plymouth harbor 15 years earlier and drew a map of native homes surrounded by fields of corn.

Where had all the people gone? As the Pilgrims thanked God for their luck, they were unaware that the previous tenants had died of a gruesome infectious disease...