During the time of the Black Death in 1348, there were many people that were killed by an infectious bacterium called "Yersinia pestis," as many as 19 to 38 million people died from this bacterium. The Black Death first spread through India then appeared in Tharsis, and then continues to spread to Muslims, Christians and Jews. This infectious disease left many people questioning how the infection was spread and what population of people would contract it. Studies showed that genetics played a large role in the distribution of the infection while others believe that it was spread wrath of god, travel, trade, resistance to antibiotics. This disease left many cities abandoned and those abandoned cities to never be occupied by a civilization again.
As stated before many question the actual spread of the disease, studies show that authentic sequences for ancient pathogens provide that the black death was caused by a Yersinia pestis variant that is found in some modern isolates. Although, Yersinia pestis was found to be the cause of the Black Death it was a variant of the disease and can only be found in medieval ancient DNA. Also, ancient forms of this disease show that there is a unique and ancestral phylogenetic placement which shows was shown through modern forms on Yersinia pestis. This study opened many doorways for helpful factors that can help identify the differences between ancient and moderns forms of diseases. Even though, this study shows that it is an ancient contracted disease and that it was spread due to the fact of genetic placement, many still believe that the spread of it was due to daily activities of the community and or the wrath of god. Many question the exact reasoning for this disease and how it was spread; I believe that a great deal of people brought it upon themselves for the spread of The Black Death.