The Plague Cycle

Heart attacks and strokes kill many more people around the world than infectious diseases; it wasn’t always that way.

Until recently, pandemics, plagues, and everyday infections of malaria, measles, yellow fever, typhus, and other diseases killed more people than all other leading causes of death – war, murder and famine – combined. History’s worst famines – in Ireland and China – killed 13% of the population. The Black Death wiped out half or more of the population in Europe in the 14th century.

More than two centuries ago, philosopher Malthus warned that growing populations would bring crowding and then disease. Competition for limited resources would cause violence and millions would perish from hunger. Malthus said these deaths would ease the pressure of excess populations. More food would be available, populations would rebound and the cycle would continue.

Malthus was wrong. Since he wrote in 1798, life expectancy and living standards have risen as populations expanded. Improved food production and distribution stymied famine. Violence, though ever-present, has subsided...