Plague still exists in various parts of the world, popping up sporadically and followed actively by the World Health Organization and Centers for Disease Control and Prevention. ( Read how modern plague strains descended from a strain that arose during the Black Death pandemic.) Plague in modern society pestis, discovering that the strain from the Justinian Plague was related to, but distinct from, other strains of the plague. From teeth of these plague victims, scientists have pieced together a family tree of Y. The high rate of fatality during these pandemics meant that the dead were often buried in quickly dug mass graves. The plague was brought to North America in the early 1900s by ships, and thereafter spread to small mammals throughout the United States. The pandemic caused roughly 10 million deaths. The cause of plague wasn't discovered until the most recent global outbreak, which started in China in 1860 and didn't officially end until 1959. Outbreaks included the Great Plague of London (1665-66), in which 70,000 residents died. The Black Death lingered on for centuries, particularly in cities. The plague killed an estimated 25 million people, almost a third of the continent’s population. It was believed to start in China in 1334, spreading along trade routes and reaching Europe via Sicilian ports in the late 1340s. Modern estimates indicate half of Europe's population-almost 100 million deaths-was wiped out before the plague subsided in the 700s.Īrguably the most infamous plague outbreak was the so-called Black Death, a multi-century pandemic that swept through Asia and Europe. Named after the Byzantine emperor Justinian I, the pandemic killed up to 10,000 people a day in Constantinople (modern-day Istanbul, Turkey), according to ancient historians. The first well-documented crisis was the Plague of Justinian, which began in 542 A.D. Three particularly well-known pandemics occurred before the cause of plague was discovered.
If left untreated, pneumonic and septicemic plague kills almost 100 percent of those it infects. If untreated, bubonic and pneumonic plague can progress to septicemic plague, infecting the bloodstream. During this stage, the disease is passed directly, person to person, through airborne particles coughed from an infected person’s lungs. Pneumonic plague, the most infectious type, is an advanced stage of plague that moves into the lungs.
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The skin sores become black, leading to its nickname during pandemics as “Black Death.” Initial symptoms of this early stage include vomiting, nausea, and fever. Transmission also occurs by handling tissue or blood from a plague-infected animal, or inhalation of infected droplets.īubonic plague, the disease's most common form, refers to telltale buboes-painfully swollen lymph nodes-that appear around the groin, armpit, or neck. When rodents die from the plague, fleas jump to a new host, biting them and transmitting Y. Scientists have more recently discovered that a flea that lives on rats, Xenopsylla cheopis, primarily causes human cases of plague. Rats have long been thought to be the main vector of plague outbreaks, because of their intimate connection with humans in urban areas. When the bacteria pass to other species, during an epizootic cycle, humans face a greater risk for becoming infected with plague bacteria. pestis can circulate at low rates within populations of rodents, mostly undetected because it doesn’t produce an outbreak.
Many small mammals act as hosts to the bacteria, including rats, mice, chipmunks, prairie dogs, rabbits, and squirrels. Once these cells are knocked out, the bacteria can multiply unhindered. pestis disables the immune system of its host by injecting toxins into defense cells, such as macrophages, that are tasked with detecting bacterial infections. pestis is an extraordinarily virulent, rod-shaped bacterium. In 1894, Alexandre Yersin discovered the bacterium responsible for causing plague: Yersinia pestis. But keen observations and advances in microscopes eventually helped unveil the true culprit.
What is plague? How many people died from the Black Death and the other plague pandemics? Learn about the bacterium behind the plague disease, how factors like trade and urbanization caused it to spread to every continent except Antarctica, and how three devastating pandemics helped shape modern medicine.įor hundreds of years, what caused plague outbreaks remained mysterious, and shrouded in superstitions.
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