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Infectious disease ecology I. - PowerPoint Presentation

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Infectious disease ecology I. - PowerPoint Presentation Infectious disease ecology I. - PowerPoint Presentation Presentation Transcript

        • Environment, Society, Climate and Health:
        • Analysis, Understanding and Prediction
        • Mark L. Wilson
        • Department of Epidemiology
        • and
        • Global Health Program
        • School of Public Health
        • The University of Michigan
        • Colloquium on Climate and Health
        • NCAR
        • Boulder, Colorado
        • 23 July, 2004
  • Outline
    • Introduction: Infectious Disease Epidemiology
    • Patterns of Environmental Influences
    • Climate as an Environmental Driver
    • Examples from our research
    • Discussion of examples from your research/interests
  • Climate Variability vs. Climate Change
    • Climate Change :
      • - persistent change or trend in mean atmospheric conditions
      • - current changes unprecedented in human history
    • Climate Variability :
      • - day-to-day (weather) or relatively short term (seasonal) changes in atmospheric conditions
      • - effects on disease patterns most easily analyzed, and used in forecasts
  • Agent Host Environment Classical Epidemiological Triad
  • Agent (diverse exposures, including non-contagious ) Host (animal, plant, ultimately human) Environment* (biophysical, psycho-social, etc.) *CLIMATE is an Environmental Influence
  • Environment Agent Host
  • Examples Involving Infectious Diseases Environment host distribution, abundance, infection longevity & infectivity outside host e.g. cholera hantaviral disease hookworm schistosomiasis Agent nutrition treatment e.g. TB, HIV/AIDS, diarrheal diseases, acute respiratory infections housing hygiene Host tissue tropisms, pathogenicity, immune response, host specificity e.g. rabies, Lyme disease, malaria, cryptosporidiosi.
  • But for ALL diseases, complex interactions occur... Agent Host Environment Altered hygiene Redesigned housing Better nutrition Improved irrigation
  • Agent Host Environment Agent transport to new areas New antibiotics, pesticides Labor actions affecting toxin exposure
  • Agent Host Environment Exposure probability, host immunity, support networks, availability of supportive care
  • Examples of Environmental and Epidemiological Data
    • Climate patterns – variability… perhaps change…
    • Land Use / Land Cover patterns
    • Human case data (specific or syndromic)
    • Vector abundance and pathogen infection
    • Reservoir abundance / infection prevalence
    • Environmental use and exposures
    • Economic development, human demography, migration … more
    Each of these is historically changing in time and space
  • Environmental Determinants of Human Disease Modified from Kaplan, 2002 Social and Economic Policies Physical Environment Institutions (including medical care) Living Conditions Social Relationships Individual Risk Factors Genetic/Constitutional Factors Pathophysiologic pathways Individual/Population Health
  • Climate? Research Challenge – Analyze and understand interactions ! Social and Economic Policies Institutions (including medical care) Living Conditions Social Relationships Individual Risk Factors Genetic/Constitutional Factors Pathophysiologic pathways Individual/Population Health
  • What is climate change? Climate variability? Time Environmental Variable Low High Average Trend (solid line) Actual Measure (dashed line) Unchanging Average, Unchanging Extremes
  • Time Environmental Variable Low High Average Trend (solid line) Actual Measure (dashed line) Unchanging Average, Increasing Extremes
  • Time Environmental Variable Low High Average Trend (solid line) Actual Measure (dashed line) Increasing Average, Unchanging Extremes
  •  
  • Time Environmental Variable Low High Average Trend (solid line) Actual Measure (dashed line) Increasing Average, Greater Extremes
  • Time Environmental Variable Low High Average Trend (solid line) Actual Measure (dashed line) Increasing Rate of Increasing Average, Unchanging Extremes
  • Time Environmental Variable Low High Average Trend (solid line) Actual Measure (dashed line) Increasing Rate of Increasing Average, Greater Extremes
  • Each of these climate change patterns may have different impacts on particular disease risks. Effects will depend on the ecology of transmission and the etiology and expression of disease.
    • Each exposure type should be considered in context of:
    • PERSON (age, behavior, gender, SES, etc .)
    • TIME (year, season, adjacent periods, etc .)
    • PLACE (geographic location, habitat, proximity, etc .)
    • Most Epidemiological studies only superficially consider this for environmental (climatic) exposures:
    • PERSON most often involves standard descriptors that do not include " social " characteristics or other environmental exposures (e.g. climatic).
    • TIME is rarely dynamic, considers only recent past, and climate pattern over long periods not always available.
    • PLACE often ignored or not carefully evaluated (e.g. spatial autocorrelation, climate patterns in regions may be important ) .
  • Environment and Exposure Anthroponotic Infections Zoonotic Infections Direct Exposure Indirect Exposure Environmental Exposures Vehicle Humans Source Stream pollutants Air Particulates Legionella Humans Humans STDs Measles Hepatitis B Vehicle Humans Humans Vehicle Malaria Dengue Roundworm Vehicle Vehicle Animals Animals Humans Lyme Disease Hantaviral Disease Most arboviral diseases Animals Animals Humans Anthrax Ebola (?) CJD Source Humans Solar UV EM Radiation Tetanus
  • Environmental Exposures Environment and Exposure Where might Climate Impact? Direct Exposure Indirect Exposure Source Humans Solar UV EM Radiation Tetanus Vehicle Humans Source Stream pollutants Air Particulates Legionella
  • Anthroponotic Infections Environment and Exposure Where might Climate Impact? Direct Exposure Indirect Exposure Humans Humans STDs Measles Hepatitis B Vehicle Humans Humans Vehicle Malaria Dengue Roundworm
  • Zoonotic Infections Environment and Exposure Where might Climate Impact? Direct Exposure Indirect Exposure Vehicle Vehicle Animals Animals Humans Lyme Disease Hantaviral Disease Most arboviral diseases Animals Animals Humans Anthrax Ebola (?) CJD
  • Elements of Climate and Health Maximum Temperature Minimum Temperature Mean Temperature Rainfall Amount Rainfall Frequency Rainfall Rate Heat-related mortality Extreme Events Air Pollution Vector-borne Diseases Water-borne Diseases Agricultural Production
  • What diseases are climate sensitive?
    • More sensitive
      • Which are more sensitive????
    High Moderate Sensitivity
    • Less sensitive
      • What about less sensitive???
    Low Lowest Sensitivity
  • What diseases are climate sensitive?
    • More sensitive
      • heat stress
      • effects of storms
      • air pollution effects
      • asthma
      • vector-borne diseases
      • water-borne diseases
      • food-borne diseases
    High Moderate Sensitivity
    • Less sensitive
      • sexually transmitted diseases
      • violence
      • most cancers
      • atherosclerosis
      • tuberculosis
      • myocardial infarction
    Low Lowest Sensitivity
  • More Complex More Climate Sensitive Heat stress Asthma Vector-borne Disease Water-borne disease Myocardial Infarction Cancer (not skin) Sexually transmitted Disease Atherosclerosis Violence Effects of Storms Food-borne disease
    • Discussion…
    • From YOUR EXPERIENCES or INTERESTS:
    • What diseases might have a climate link and what climate variables might impact on which diseases?
    • WHY? What are the biological or social pathways?
    • How would these be investigated/researched?
    • What additional information would you seek?
    • How would you integrate this into OTHER determinants of risk?
    • Could you forecast risk based on these analyses alone?
    • What other factors should be considered and why?
  •  
    • Importance of temporally and spatially extensive data in analyzing and interpreting role of climate:
    • Climate change occurring over long time period
    • Climate variability change not easy to recognize without long-term observations
    • Time-space changes in disease patterns require accurate and consistent surveillance (often non-existent, especially in developing countries)
    • Inference of climate-disease links limited without carefully considering time-space patterns
  • Interpreting Spatial Patterns of Risk
    • Area of risk
    • Size of areas
    • Location and pattern
    • Inter-area distances
    • Connectivity among locations
    a b c d
  • How can extensive time-space datasets help? T 1 T 2 T 3 Pattern of disease … or knowledge, SES, exposure, etc...
  • How can extensive time-space datasets help?
  • How can extensive temporal datasets help? Time Abundance / Prevalence
  • How can extensive temporal datasets help? Establishment and Colonization Dispersal, Invasion, Extinction, Reinvasion Inter-annual Fluctuations Time Abundance / Prevalence
  • How can extensive spatial datasets help? Environmental Index Abundance or Infection Low High Low High Habitat Fragmentation Change in Suitable Habitat Distance from Source Climate variable
  • Some Sources of Data
    • Meteorological Stations (climate, weather)
    • Satellite – climate, vegetation, soil moisture, etc
    • Census: population, age, sex, location, etc…
    • Passive or active surveillance of human cases
    • Surveillance of vector, reservoir abundance
    • more...
  • Knowing is not enough; we must apply. Willing is not enough; we must do. (Goethe)