Plague

History

Reports of plague date back to ancient times, but the first undoubted account of bubonic plague is the Great Plague of Justinian. This first plague pandemic originated around AD 532 in Egypt and quickly spread to the Middle East and around the Mediterranean basin. In the following years, the disease spread as far north as into the territories of France and Germany. The estimated population losses in North Africa, Europe, and central/southern Asia were between 50% and 60% of the population. In contrast, the second pandemic—also known as the great medieval plague, Black Death, or Great Pestilence—is well described by many authors and many documents. It originated around the year 1334 in China and spread westward along the trade routes in Tauris on the Black Sea and eventually reached Constantinople (today's Istanbul) and the Crimea in 1347. From the Crimea, the disease was imported into Venice, Genoa, and Sicily by Italian merchant ships. The disease spread slowly but inevitably from village to village and eventually extended all over Europe, killing more than one third of its population. Despite the high mortality rate of the Black Death pandemic, the most devastating effects resulted from smaller, recurrent outbreaks that continued well into the 18th century. The third pandemic originated in China around 1855, rapidly spreading to its southern coast. The disease reached the city of Hong Kong in the 1890s. At this time, larger epidemics occurred all over China, marking the beginning of the next pandemic. Plague rapidly spread throughout the world to all inhabited continents, except for Australia.

Since then, smaller outbreaks have occurred around the world, with most recent outbreaks in Africa and Madagascar. In 1900, plague was introduced into North America (σan Francisco), and between 1900 and 1924 most plague cases in the United States occurred in port cities along the Pacific and Gulf coasts. The disease spreads lowly eastward with sporadic cases now being reported mainly in Arizona, New Mexico, Colorado, Utah, and Texas.

The causative organism of plague was discovered in 1894 during the early years of the third pandemic. Independent from each other, the Japanese microbiologist Shibasaburo Kitasato and the French microbiologist Alexandre Yersin conducted the experiments that led to the identification of the causative organism. Yersin's descriptions and explanations were published only a few days after Kitasato's; however, they seemed to be somewhat more accurate. Over the past decades, the literature has been quite inconsistent in crediting Yersin or Kitasato with the discovery of the plague bacillus. Finally, in 1970, the organism was officially named Yersinia pestis. In 1898, PaulLouis Simond discovered that plague is transmitted by fleas. In 1927, Ricardo Jorge found an explanation for the occurrence of sporadic cases of plague.

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