Epidemiologic transition is when causes of death change from infectious diseases to chronic degenerative diseases. This change means that people die at an older age.
The theory was formulated by Abdel Omran in 1971.
The theory states there are three stages:
- The age of pestilence and famine
- The age of receding pandemics
- The age of chronic diseases.
The age of pestilence and famine took place one thousand years ago with the development of the agricultural society. The result is that infections became more common due to the accumulation of waste, contact with animals and contagion from one person to another. Major pandemics are cholera, influenza, plague, small pox and typhus. There was also a lack of food and water. It is the age of pestilence and famine. This situation prevails still in some developing countries.
In the second age pandemics recede. Medical treatment is still at its early stage but there are a number of improvements such as drinkable water, sewage treatment, more available food, increased pre- and post-natal care. Antibiotics and vaccination made their appearance eliminating death from certain infectious diseases.
Industrialization and lifestyle changes are a cause of pollution leading to allergies, autoimmune disorders and sexually transmitted diseases. Consequently, there is a sharp increase in population.
In the age of chronic diseases, the main causes of death are cancer, cardiovascular diseases and diabetes. There are law levels of fertility and mortality, and therefore there is no population growth.
These ages take place at different times in each country.
Nevertheless, certain pandemics still appear and cause major diseases and mortality.