The Black Death was the single greatest mortality event in recorded history. Caused by the bacterium Yersinia pestis, the bubonic plague pandemic swept through North Africa, Europe, and Asia nearly 700 years ago, wiping out up to 30-60% of the population. Newly reported research now suggests that the pandemic placed a a significant selective pressure on the human population, changing the frequency of certain immune-related genetic variants and affecting our susceptibility to disease today.
