Robin Cochran-Dirksen The Effect of Climate on Infectious Disease What changes will occur epidemiologically? What changes will occur epidemiologically?

Robin Cochran-DirksenRobin Cochran-Dirksen

The Effect of Climate on Infectious The Effect of Climate on Infectious DiseaseDisease

• What changes will occur epidemiologically?What changes will occur epidemiologically?• How do we correlate changes in climate to How do we correlate changes in climate to

global changes in infectious disease?global changes in infectious disease?• What technologies and tools are used to What technologies and tools are used to

analyze, predict, and monitor disease spread?analyze, predict, and monitor disease spread?


Kinds of health impacts resulting from Kinds of health impacts resulting from climate change:climate change:

• Direct- result from weather extremes.Direct- result from weather extremes.• Consequences from ecological disruption.Consequences from ecological disruption.• Consequences resulting from climate-induced Consequences resulting from climate-induced

economic disruption, e.g. traumatic, infectious, economic disruption, e.g. traumatic, infectious, nutritional, psychologicalnutritional, psychological

• Changes in human health as a result of climate Changes in human health as a result of climate change will be indicated by alterations in geographic change will be indicated by alterations in geographic range and seasonality of infectious diseases.range and seasonality of infectious diseases.


Challenges to connecting changes in Challenges to connecting changes in infectious disease to climate change.infectious disease to climate change.

•Climate influences are modulated by Climate influences are modulated by interactions with other ecological processes, interactions with other ecological processes, social conditions, and adaptive policies.social conditions, and adaptive policies.•Climate change is just one environmental Climate change is just one environmental change that simultaneously impact human health.change that simultaneously impact human health.


Determinants of vectorborne diseasesDeterminants of vectorborne diseases

• Vector survival and reproductionVector survival and reproduction• Biting rateBiting rate• Incubation rateIncubation rate


The tasks of the researchersThe tasks of the researchers

1.1. Establishing baseline relationships between Establishing baseline relationships between weather and health.weather and health.

2.2. Seeking evidence of early effects of climate Seeking evidence of early effects of climate change.change.

3.3. Scenario-based predictive modelsScenario-based predictive models4.4. Evaluating adaptation optionsEvaluating adaptation options5.5. Estimating the co-incidental benefits and Estimating the co-incidental benefits and

costs of mitigation and adaptation.costs of mitigation and adaptation.


Environmental factors affecting Environmental factors affecting infectious diseaseinfectious disease

• Warmer temps enhance vector breeding and Warmer temps enhance vector breeding and reduce the pathogens maturation time within reduce the pathogens maturation time within the vector.the vector.

• Expanded pathogen/vector range introduces Expanded pathogen/vector range introduces the pathogen to populations with little the pathogen to populations with little protective immunity.protective immunity.


Social factors affecting healthSocial factors affecting health

• Population densityPopulation density• Level of economic development of the Level of economic development of the

countrycountry• Food availabilityFood availability• Pre-existing health statusPre-existing health status• Availability of health careAvailability of health care


Historic evidence of the connection of Historic evidence of the connection of climate to infectious diseaseclimate to infectious disease

• The link of climatic events has been studied The link of climatic events has been studied for a century in the Punjab.for a century in the Punjab.


Applying Technologies: Types of Applying Technologies: Types of ModelsModels

•StatisticalStatistical•Process BasedProcess Based•Landscape-based ModelsLandscape-based Models


Statistical ModelsStatistical Models

• Work by deriving the relationship between Work by deriving the relationship between current geographic distribution and the current geographic distribution and the current location-specific climatic conditionscurrent location-specific climatic conditions

• These models have been applied to climate These models have been applied to climate impacts on malaria, dengue fever and in the impacts on malaria, dengue fever and in the U.S., enchephalitis.U.S., enchephalitis.


Process-based (mathematical) modelsProcess-based (mathematical) models

• Use equations that express the scientifically Use equations that express the scientifically documented relationship between climatic documented relationship between climatic variables and biological parameters- e.g., variables and biological parameters- e.g., vector breeding, parasite incubation rate,vector breeding, parasite incubation rate,


Landscape-based ModelingLandscape-based Modeling

• Combines the first two models with the use of Combines the first two models with the use of spatial analytical methods, to study the effects spatial analytical methods, to study the effects of both climatic and other environmental of both climatic and other environmental factors (e.g. different vegetation types- often factors (e.g. different vegetation types- often measured, in the model development stage by measured, in the model development stage by ground-based or remote sensors).ground-based or remote sensors).


Models allow them to create rubrics:Models allow them to create rubrics:


A Specific Example of Model A Specific Example of Model ApplicationApplication

• A study called Regional-scale climate-A study called Regional-scale climate-variability synchrony of cholera epidemics in variability synchrony of cholera epidemics in West Africa was published in 2007 in West Africa was published in 2007 in Infectious DiseaseInfectious Disease

• Methods: Wavelet and derived analyses of the Methods: Wavelet and derived analyses of the evolution of the periodic component over evolution of the periodic component over time.time.


Wavelet analysesWavelet analyses



Another exampleAnother example

• A monitoring program over several years in a A monitoring program over several years in a lake in Austria in order to identify the lake in Austria in order to identify the preferred niche.preferred niche.

• Findings: they discovered a significant Findings: they discovered a significant correleation of the frequency of V. cholerae correleation of the frequency of V. cholerae with temperature, zooplankton biomass, and with temperature, zooplankton biomass, and conductivity.conductivity.



The FutureThe Future

Climate Change Global Risks, Challenges & Decisions Climate Change Global Risks, Challenges & Decisions ConferenceConference

Held in Copenhagen 10-12 March, 2009 was attended Held in Copenhagen 10-12 March, 2009 was attended by more than 2,500 delegates from almost 80 by more than 2,500 delegates from almost 80 countries.countries.

The synthesis report will be published in June and The synthesis report will be published in June and presented to all participants at the UN Climate presented to all participants at the UN Climate Change Conference to be held in DecemberChange Conference to be held in December

Documents

Robin Cochran-Dirksen The Effect of Climate on Infectious Disease What changes will occur epidemiologically? What changes will occur epidemiologically?