APHG Unit 2

The Epidemiological Transition Model (ETM) describes the changing patterns of disease and death within a population over time. It closely aligns with the Demographic Transition Model (DTM), illustrating how population health shifts alongside population growth and development.

Where it fits in the Demographic Transition Model:

The ETM is considered a sub-model of the DTM. It complements the DTM’s focus on population growth and age structure by explaining the corresponding changes in disease profiles.

Stages of the Epidemiological Transition Model:

Stage 1: Age of Pestilence and Famine (High Mortality)

• Characteristics:
  • High death rates from infectious diseases (e.g., plague, smallpox, cholera)
  • Famine and malnutrition are common
  • Life expectancy is low (around 30 years)
  • Limited access to sanitation and healthcare
  • Corresponds to Stage 1 of the DTM (high birth and death rates)

Stage 2: Age of Receding Pandemics (Declining Mortality)

• Characteristics:
  • Improved sanitation, hygiene, and nutrition
  • Infectious diseases decline, but still prevalent
  • Life expectancy increases (40-50 years)
  • Emergence of chronic diseases (e.g., heart disease)
  • Corresponds to Stage 2 of the DTM (declining death rates, high birth rates)

Stage 3: Age of Degenerative and Man-Made Diseases (Moderating Mortality)

• Characteristics:
  • Further decline in infectious diseases
  • Rise in chronic diseases (e.g., heart disease, cancer, diabetes)
  • Life expectancy continues to increase (60-70 years)
  • Increased emphasis on healthcare and preventative measures
  • Corresponds to Stage 3 of the DTM (declining birth rates, low death rates)

Stage 4: Age of Delayed Degenerative Diseases (Low Mortality)

• Characteristics:
  • Further decline in chronic diseases due to advancements in medicine and lifestyle changes
  • Increased life expectancy (70+ years)
  • Focus on extending healthy lifespan
  • Emergence of new health challenges like lifestyle-related diseases and mental health issues
  • Corresponds to Stage 4 of the DTM (low birth and death rates, stable population)

Stage 5 (Hypothetical): Age of Emerging and Re-emerging Infectious Diseases (High Mortality)

• Characteristics:
  • Potential rise in infectious diseases due to factors like antibiotic resistance, globalization, and environmental changes
  • Increased risk of pandemics
  • This stage is hypothetical and has not yet been fully realized.

Key Points:

• The ETM highlights the dynamic nature of disease patterns and the importance of public health interventions.
• The stages are not always linear and can vary between countries and populations.
• Factors like economic development, access to healthcare, and environmental conditions influence the transition process.