Historical Measures and Biological Factors That Contained the Black Death Pandemic

The Black Death pandemic that began in 1347 killed an estimated 25-50 million people across Europe. Caused by the Yersinia pestis bacterium transmitted via fleas on black rats, the disease spread through trade routes. Authorities in cities like Ragusa and Venice implemented early quarantine measures in 1377, requiring isolation periods of 30-40 days and establishing specialized hospitals. Social adaptations included shifts to stone housing and improved hygiene practices. Over time, human genetic resistance developed through natural selection, and the bacterium itself evolved into less virulent forms, reducing mortality in subsequent outbreaks.