Introduction

• Emerging infectious diseases: seen as a big problem currently

• Emerging infections: are not a recent phenomenon but have always played a major role throughout human history

• 3 epidemiologic transitions

• Importance of anthropology for research

An Overview of Epidemiological Transitions

• Omran’s model criticisms

  • Implies each stage of the transition is more advanced and desirable than the previous stages

  • Using whole nations as units of analysis: buries the differential experience according to race, gender, and class

  • Restricted to a particular set of historical circumstances in the recent shift

Epidemiological Transitions: From the Late Paleolithic Age to the Industrial Revolution

Paleolithic Age Baseline

• Populations were too small and dispersed to support communicable pathogens

• Pinworm

• Ectoparasites

• Enteric pathogens

• Rate of emergence of diseases: may have increased as tool use allowed exploitation of novel ecological niches and as migration increased

The First Epidemiologic Transition

• Sedentism: led to larger groups + more interaction between people

• Increase in infectious disease mortality

• Accumulation of human waste

• Appearance of domesticated animals: provided a reservoir for zoonoses

• Agricultural practices

• Nutrient deficiencies

• Groups that most suffered: women, children, lower classes

• Increased severity of diseases

• Crowding in urban centers

• Epidemic outbreaks

• Increasing migration + trade: transmission of diseases

• Exploration + conquest: infections of Native Americans leading to pandemics

The Second Epidemiologic Transition

• Industrial Revolution

• Decline in infectious disease mortality within developed countries

  • Landmark for modernization

• Nutritional factors

• Extension of life expectancy: increased morbidity from chronic diseases

  • Cancer, diabetes, etc.

• Increasing of water + air pollution

• Differences in mortality based on social inequalities

• Improvements in child survival and life expectancy at birth in less developed nations

  • Immunizations + antibiotics

The Third Epidemiologic Transition

• Emerging infectious diseases

• New diseases: contribute to adult mortality

• Increased incidence and prevalence of pre-existing infectious diseases that were thought to be under control

• Generation of antimicrobial-resistant strains at a faster rate than safe new drugs is developed

Recently Emerging Infections

• 29 newly emerged pathogens since 1973

  • May be due to increases in detection rates

• Examples: HIV, Ebola, Marburg, Lyme disease, dengue fever, malaria, tuberculosis

  • Earlier transmission of HIV to urban Haiti: by more affluent Westerns engaging in sex tourism

• These new outbreaks are linked to climatic fluctuations and ecological disruptions

• Re-emerging infections causes: warmer climates, climatic fluctuations, poorly developed urban environments, increase in mosquito populations, decreases public health expenditures, poverty,

• Inevitability of genetic adaptations of microorganisms to the selective conditions posed by human technology and behaviors

• Host susceptibility and comorbidity

• Overuse of antibiotics in industrial animal: causes the rise of multi-drug resistant strains of food-borne pathogens

• Human populations are converging into a single global disease ecology