The plague killed millions of people all over the world. There is no real reason on how the disease died out but people believed that climate change played a vital role. Increase in temperatures killed animals carrying the disease and even people perished due heat strokes. Other sources believe that almost all people were infected with the disease and hence the disease could not spread any further. Although, this might not be the case as the plague returned subsequently in the 14th to the 19th century. Australia was plagued by the black death in the 19th century. Killing all rats and fleas in the country appeared very successful resulting in the plague disappeared from Australia in a matter of 3 years.