The document provides information about the Black Death pandemic that ravaged Europe between 1347 and 1351. It began in China and spread to Europe through trade routes. The disease was caused by the Yersinia pestis bacterium, which was often transmitted via fleabites from infected rodents. It took various forms including bubonic plague, which caused swollen lymph nodes, and pneumonic plague, which infected the lungs. Crowded cities with poor sanitation helped the disease spread rapidly, killing an estimated 25 million people in Europe - almost one-third of the population. The pandemic had long-lasting social and economic impacts, such as a shortage of labor that improved conditions for peasants and workers.