As the nineteenth century advanced, many industrialized countries saw the beginnings of an epidemiological transition wherein a shift took place in the dominant causes of death: from fatal infectious diseases of rapid progression, to chronic and life-threatening diseases of longer duration.

As the nineteenth century advanced, many industrialized
countries saw the beginnings of an epidemiological transition
wherein a shift took place in the dominant causes of death:
from fatal infectious diseases of rapid progression, to chronic
and life-threatening diseases of longer duration.