Role of climate change in epidemiology of infectious diseases


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Presented by Delia Grace at the Field Epidemiology and Laboratory Training Programme (FELTPK), Kenya, 24 October 2012.

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Role of climate change in epidemiology of infectious diseases

  1. 1. Role of climate change in epidemiology of infectious diseases Delia Grace Component Leader: Agriculture Associated Disease CGIAR Research Program on Agriculture for Nutrition and Health Field Epidemiology and Laboratory Training Programme in Kenya, 24 October 2012
  2. 2. Invited lecture FELTPK Residents during the “One Health WeekThe Field Epidemiology and Laboratory Training Programme (FELTPK) in Kenya is a two-year postgraduate competencybased training program in applied epidemiology and public health laboratory management. It was established in April 2004to enable frontline public health professionals acquire the latest knowledge and skills that address global threats to publichealth, using training-through-service approach.The program collaborates closely with the United States Centers for Disease Control and Prevention (CDC).Upon completion of all requirements, FELTPK graduates are awarded degrees in a Master of Science (Msc) inApplied Epidemiology or Msc in Laboratory Management and Epidemiology from Jomo Kenyatta Universityof Agriculture and Technology (JKUAT). Other key collaborating partners include Kenya Medical ResearchInstitute (KEMRI), Ministry of Medical Services and Ministry of Public Health and Sanitation, Ministry ofLivestock Development, World Health Organization (WHO), World Bank and the African Field EpidemiologyNetwork (AFENET).Following the need to strengthen "One Health" initiatives in Kenya, FELTPK enrolled four (4) veterinaryofficers from the Ministry of Livestock Development this academic year. This was followed by designing a onehealth module that is to be delivered to the cohort 9 residents which constitutes a class of 18 residents.The following lecture “Role of Climate Change in Epidemiology of Infectious was requested by Dr SamuelAmwayi.
  3. 3. International Livestock Research Institute •a member of the CGIAR Consortium, ILRI conducts livestock, food and environmental research  to help alleviate poverty  and improve food security, health & nutrition,  while protecting the natural resource base.  Indi Mali a 700 full time staff-1000 total 100 scientists & researchers 54 from 22 developing countries Chin more than 30 scientific a disciplines Vietna m 2012 budget USD 60 million ILRI works with a range of Laos research & development partners Nigeria across 7 CGIAR research Mozambiqu programs e Kenya Ethiopi Thailan a d
  4. 4. Overview• Ecohealth/ One Health• Our changing planet – Warmer, wetter, weirder – Implications for Africa and Kenya – Role of agriculture in climate change• Climate and infectious disease – How does climate affect infectious disease? – Climate sensitive infectious diseases • Vector-borne disease • Flood-associated disease • Food-borne disease – Climate sensitive non-infectious disease• Implications for field epidemiologists• Conclusions
  5. 5. Key concept One world – one healthGaiaHypothesis Ecosystem Agroecosystem Approach to Health Ecosystems „One Medicine“ Human Animal health Societies Human health Economies health Veterinary Public Peace Health Institutions “Syndrome approach” • One Health is the collaborative effort of multiple disciplines to attain optimal health for people, animals, and our environment. • Ecohealth is systemic, participatory approaches to understanding and promoting health and well-being in the context of social and ecological interactions (Waltner-Toews D (2009), Can. Vet. J., 50(5): 519–521.).
  6. 6. Key definitions• Climate = average weather in time & place (IPCC)• Climate change = Statistically significant variations in mean state of the climate or of its variability persisting for decades• Climate scenario = a plausible representation of future climate based on climatological relationships• Extreme weather event = often, rarer than the 10th or 90th percentile• Greenhouse effect = greenhouse gases absorb infra-red radiation effectively trapping heat near the planet surface. Water vapour, CO2, nitrous oxide, methane and ozone are the most important• Global warming = average increase in the temperature of the near the earth’s surface• IPCC = Intergovernmental Panel on Climate Change= leading international body for assessment of climate change, established by UNEP and WMO in 1988
  7. 7. Key Resources: IPCC reports• First assessment report 1990 – several paragraphs on health• Second assessment report 1995 – chapter on potential health risks• Third assessment report 2001 – chapter on human health potential impacts via: – Thermal stress (heat waves and cold spells) – Extreme events and disasters – Air pollution – Infectious diseases• Fourth assessment report 2007 – review of health impacts. Evidence suggests climate change has: – Altered seasonal distribution of some allergenic pollen – Increased heat wave related deaths – Altered distribution of some vectors (mosquito, sand fly) – Climate influences malaria, dengue, TBD, cholera and some diarrhoeal disease
  8. 8. Climate skeptics?• Consensus – 97-98% of scientists most active in the field believe global warming is occurring – 90% believe mostly due to human activity• Caveats – Planet has been warmer in the past – Role of geo-engineering in mitigation unknown
  9. 9. Source: IPCC Climate Change 2007: The Physical Science Basis: Summary for Policymakers Our Changing Planet: Warmer, wetter, weirder “Virtually certain” Over most land areas • Warmer, and fewer cold days and nights. • Warmer, and more frequent hot days and nights “Very Likely” Over most areas • Warm spells / heat waves. • Heavy precipitation events. • Generally (3/4 land area) wetter; some areas (1/4) drier. “Likely” • Area affected by droughts increases. • Intense tropical cyclone activity increases. • Increased incidence of extreme high sea level.
  10. 10. There may be winners as well as losers …Simulated percentage pasture production changes to 2030 and 2050, by country and system National Mixed rainfed Mixed rainfed Mixed rainfed Production temperate humid arid 2030 2050 2030 2050 2030 2050 2030 2050 Burundi 9 9 14 18 -2 -9 - - Kenya 15 18 33 46 -5 -10 -1 -8 Rwanda 11 15 13 19 5 4 1 3 Tanzania -3 -8 7 9 -2 -6 -5 -11 Uganda -2 -9 5 3 -5 -13 -1 -6 Mean of 4 combinations of GCM and emissions scenarios Winners Losers Thornton et al. (2010)
  11. 11. Climate change in drylands CENTRAL ASIA Temp: +3.7 C Rain: -3% Drought yrs: +12%SAHARATemp: +3.6 CRain: -6%Drought yrs:↑ EAST AFRICA Temp: +3.2 C WEST AFRICA Rain: +7% Temp: +3.3 C SOUTHERN ASIA Flood yrs: +30% Rain: +2% Temp: +3.3 C Drought yrs: +1% Flood yrs: +22% Rain: +11% Flood yrs: +39% Drought yrs: +3% Source: IPPC working group 1, 2007
  12. 12. • Livestock:9- 18% anthropogenic emissions• 80% agricultural emissions Contributors to climate change
  13. 13. Overview• Ecohealth/ One Health• Our changing planet – Warmer, wetter, weirder – Implications for Africa and Kenya – Role of agriculture in climate change• Climate and infectious disease – How does climate affect infectious disease? – Climate sensitive infectious diseases • Vector-borne disease • Flood-associated disease • Food-borne disease – Climate sensitive non-infectious disease• Implications for field epidemiologists• Conclusions
  14. 14. Warmer, wetter, wider variation → sicker? Warmer Wetter / (drier) Wider variationD ↑ growth rate ↑ ↓ Survival in air Post disaster ↓ generation time ↑ Faecal-oral disease ↑ ↓ survival transmission Endemic instability ↑ season ↑ Movement in water Spread/shrinkage ↑ activityI Wildfires Change farming systems Air Pollution (O3, PM, GHG) Population movements Nuisance Plants Increase in biomass More intense air movement Change trade patterns
  15. 15. Group work:What important diseases in Kenya may be climate sensitive
  16. 16. Conceptualising CSDVector-borne Malaria, dengue, WNV, Shifting distribution of vectorsdisease RVF, TBE, Lyme, Higher temperatures affect vectorial capacity and leishmaniasis, feeding frequency trypanosomosis, Drought & heavy rain leads to population surges schistosomiasis, onchocerciasisWater associated Cholera, Disaster and lack of sanitation cryptosporidiosis, Flooding and run-off leptospirosis Higher water temperatureFood borne Salmonella, E. coli, Lack of sanitation Campy, ListeriaAir borne Meningitis, Q fever Higher RH allows survival (FMD) DustSoil associated Anthrax Temperature, RH and soil moisture affect spore Clostridial disease germination Heavy rainfall stirs up dormant sporesRodent borne Hanta virus; Lasa fever virusMultistage Fascioliasis Conditions favour intermediate hostsparasites
  17. 17. WHO conceptual framework Modulating Health effects Adaptive influences Temperature-related capacity illness and death Mitigative Extreme weather- capacity related health effects • Regional Microbial weather contamination Air pollution-related changes pathways health effects Mitigation • Heatwaves Transmission Water and food-borne Driving measures dynamics diseases forces • Extreme weather Vector-borne and Greenhouse CLIMATE Agro- Population rodent-borne diseases gases (GHG) ecosystems, dynamics CHANGE • Temperature emissions hydrology Effects of food and Unsustainable • Precipitation Socioeconomics, water shortages economic demographics development Mental, nutritional, infectious and other health effects Natural causes Health-specific adaptation measures Research needs Evaluation of adaptationSource: Climate Change and Human Health – Risks and Reponses. Summary (WHO, 2003)
  18. 18. HOW CLIMATE AFFECTS INFECTIOUS DISEASES OF LIVESTOCK AND PEOPLE (Vector-borne, parasitic,, air-borne, soil-borne, water-borne, food borne)Seasonal Short-term Medium-term Long-term(within year) (1-5 years) (5-15 years) (15-40 years)Environment•Vegetation Vectors•Land cover Arthropod and other invertebrate•Relative humidity vectors of infectious agents•Surface water•Soil•Ambient temperature Human populations as definitive and aberrant hosts,Animal populations, as definitive, and transporters of fomitesintermediate and amplifier hosts •Animal owners•Domestic livestock •Rural dwellers•Wildlife •Consumers of animal foods•Companion animalsMore extreme events Raising sea levels Increased temperature, Regional shifts in climate increased precipitation envelopes
  19. 19. Annual human deaths early 21st centuryAll infectious 18,000,000Diarrhoea (50% zoonotic) 3,000,000Road traffic 1,200,000Leptospirosis 123,000 & pig/dairy productionCysticercosis 50,000 & pig productionExtreme weather related 20,000Predicted climate change 150,000Malaria 1,000,000Dengue 20,000Sleeping sickness 50,000 & exclusion farming & productionLeishmaniasis 47,000 & companion animalQ fever 3,000 & sheep, goat, dairy production, emergingLyme disease 2,000 & emergingWest Nile fever 100 & equine losses, emergingRift valley fever 45 & sheep production, trade, emergingEmerging disease ???? 20
  20. 20. Drivers of changeGNDP
  21. 21. Malaysia: climate and malaria 1961: Pilot Malaria Eradication Project 2004:300000 1990-92: Field trial Renewed 30 1967-1971: MEP on insecticide treated bednet studies on 1972-1981: Anti- (ITN) simian Malaria Program malaria 1982: Vector-borne Diseases Control Program- Policy, program & strategy development Number of Cases Temperature 1993: Nationwide 2003: National Drug Resistance Use of ITN Surveillance Program 2006: National Treatment Review Committee: ACT 50000 25 0 1961 1970 1980 1990 2000 2005
  22. 22. Overview• Ecohealth/ One Health• Our changing planet – Warmer, wetter, weirder – Implications for Africa and Kenya – Role of agriculture in climate change• Climate and infectious disease – How does climate affect infectious disease? – Climate sensitive infectious diseases • Vector-borne disease • Flood-associated disease • Food-borne disease – Climate sensitive non-infectious disease• Implications for field epidemiologists• Conclusions
  23. 23. Vector-borne diseases• Malaria• Arboviral diseases transmitted by mosquitoes, midges or biting flies – RVF – Yellow Fever – WNV – Dengue – Japanese encephalitis• Ticks and tick-borne diseases – Lyme disease – Tick borne encephalitis• Tsetse-transmitted trypanosomosis• Chagas disease• Onchocerciasis
  24. 24. Flood-borne diseases• Water-borne disease • Response – Major risk is contaminaiton of drinking water• • Chlorination Water-borne epidemic – Leptospirosis • Early malaria diganosis• Vector-borne disease • Vaccination high risk groups – Malaria • Health education – Dengue – West Nile virus – Rift Valley fever • Long term• Risk posed by corpses • Disaster preparedness – Most agents do not surrvie in corpses (HIV is an exception up to 6 days) – Routine handling of corpses puts at risk of TB, bloodborne viruses, gastro-intestinal illness• Other risks – Drowning, injurty, trauma – Hypothermia – Psycho socail distess
  25. 25. Food-borne diseases• Campylobacteriosis, salmonellosis, Salmonella Typhimurium infections and Salmonella Enteritidis positiviely associated with temperature 2-5 wks earlier (Lake et al., 2009)• Air temperature: Campylobacteriosis and salmonellosis• Water temperature: campylobacteriosis and non-cholera vibrio infections• Precipitation frequency: cryptosporidiosis followed by campylobacteriosis;• Precipitation events: cryptosporidiosis followed by non-cholera vibrio• Listeria sp. was not associated with temperature thresholds, extreme precipitation events, or temperature limits (ECDC, 2012).
  26. 26. Emerging disease Source (Nature, 2004, 430:242-249)• Of 1500 human infectious diseases, 58-65% zoonotic, • One new disease emerges every 7 months• Around 150 to 200 EID75% of EID zoonotic
  27. 27. Malaria vector in Africa A= current B- D: different climate scenarios CLIMEX model West Africa becomes less suitable vectors shift east & south Tonnang et al, 2010, Malaria journalDistribution of A. arabiensis
  28. 28. HAT in AfricaA= current geographical range suitable for T. b. rhodesience B= A2 climate change scenario 2055SEIR model and IPCC dataRange increases by 10%; considerable shifts – foci in Ethiopia disappearMoore et al 2012; J. R. Soc Interface
  29. 29. Anthrax in KazakhstanA= current scenarioB= A2 scenario (drastic)C= B2 scenario (milder)IPCC & historical anthraxdatasets; GARP modelJoyner et al, 2010, PLOS 1
  30. 30. Malaria VERY HIGH RVF Cholera Meningitis HIGHClimate sensitivity Jap. Enceph, Denge, RVF, ECF, West Nile, Heartwater Ectoparasites Yellow fever, MODERATE Lyme Worms Leishmaniaiss Filiarisis, sleeping Diarrhoea, sickness Respiratory Anthrax, Dermatophilosi Worms, tryps blackleg sresp. complex STD HIV, Trachoma, Childhood LOW onchocerciasis TB, illness schistosomiasis LOW MODERATE HIGH Very HIGH <0.25 m DALY or no data 0.25 to 1 m DALY 1 to 12 m DALY >12 m Daly Health burden
  31. 31. Which CSD are most important to the poverty/ls nexus: the big fiveAnimal disease Zoonotic disease Human disease• • Diarrhoea • Malaria Ticks and TBD• • Arbovirus: Dengue, • Diarrhoea Arbovirus: RVF, JE YF, JE • Respiratory• Internal parasites • Schistosomiasis • Arbovirus• Trypanosomosis • Sleeping sickness • Worms• Culicoides • Tuberculosis transmitted virus – BT, AHS
  32. 32. Overview• Ecohealth/ One Health• Our changing planet – Warmer, wetter, weirder – Implications for Africa and Kenya – Role of agriculture in climate change• Climate and infectious disease – How does climate affect infectious disease? – Climate sensitive infectious diseases • Vector-borne disease • Flood-associated disease • Food-borne disease – Climate sensitive non-infectious disease• Implications for field epidemiologists• Conclusions
  33. 33. Implications for epidemiologists•Non infectious disease – Extreme heat, extreme events•Disease dynamics – Shifts, increase, decrease – Emergence•Human adaptation – People movement – Irrigation – More and different livestock
  34. 34. Different ways to manage risk: from cows to camels • Northern Kenya: reduction in cattle numbers (10%) and increase of camels (78%) • Lower mortality, more milk = more food and income security But Coxiella burnetti : 31% Brucellosis: 5% Trypanosoma: 8% Orf/pox: 35% (Deem et al., 2012) Courtesy Mario Herrero, ILRI
  35. 35. An example of climate-induced livelihood transitions 20º Areas where cropping of an indicator cereal may 0º become unviable between now and 2050 and where farmers may have to rely more on livestock as a livelihood -20º strategy Jones & Thornton (2008) 0º 20º 40º
  36. 36. Overview• Ecohealth/ One Health• Our changing planet – Warmer, wetter, weirder – Implications for Africa and Kenya – Role of agriculture in climate change• Climate and infectious disease – How does climate affect infectious disease? – Climate sensitive infectious diseases • Vector-borne disease • Flood-associated disease • Food-borne disease – Climate sensitive non-infectious disease• Implications for field epidemiologists• Conclusions
  37. 37. conflict Large-scale population milieu for catastrophic dislocation emerging diseases, e.g. multi-drug –resistant TB, artemisinin-resistant failing malaria, HIV, others governanceSea level Impaired rise public (future) health Rising food worse global prices nutrition High Climate energy Increased use change costs of crops for fuel Butler, in press (2012) Dependence on fossil fuel,declining in quantity, quality and accessibility
  38. 38. Less conflict Improved public health Lessclimate Improved Better global education andchange governance communication, slower population growth, fairer Stable food global society, new ways to prices measure progress, new ways of thinking, less food waste, meat consumption “contracts and converges” Clean abundant energytechnologies, especially solar Butler, in press (2012)
  39. 39. Further reading courtesy of Jibrin Idris Manu• Baede A.P.M., Ahlonsou E., Ding Y., Schimel Bolin B., and Pollonais S (-) The Climate System: an Overview• ANTHONY MCMICHAEL ., ANDREW GITHEKO., R. Akhtar., R. Carcavallo., D. Gubler A. Haines., R.S. Kovats., P. Martens ., J. Patz ., A. Sasaki Human Health• Anthony J McMichael Jonathan Patz and R Sari Kovats (1998). Impacts of global environmental change on future health and health care in tropical countries. British Medial Bulletin;54 (No. 2): 475-488• A.J. McMichael., D.H. Campbell-Lendrum., C.F. Corvalán ( 2003) Climate change and human health Risks And Responses• Van den Bossche & Coetzer, 2008, Climate change and animal health in AfricaRev. sci. tech. Off. int. Epiz., 2008, 27 (2), 551-562• WHO, Flooding and communicable diseases•• Climate and health 41
  40. 40. Definition• Climate varies from place to place, depending on latitude, distance to the sea, vegetation, presence or absence of mountains or other geographical factors.• It varies also in time; from season to season, year to year, decade to decade or on much longer time- scales, such as the Ice Ages• Climate change refers to statistically significant variations of the mean state of the climate or of its variability, typically persisting for decades or longer03/20/13 42
  41. 41. DEFINITION• The climate system is an interactive system consisting of the atmosphere, hydrosphere, cryosphere, land surface and the biosphere• The system is influenced by various external forcing mechanisms; the Sun and human activities• A balance is maintained between incoming solar radiation and the outgoing radiation emitted by the climate system.• Climate change refers to any significant change in measures of climate, such as temperature, precipitation, wind, and other weather patterns, that lasts for decades or longer. (CDC, climate change Website)03/20/13 43
  42. 42. Greenhouse gases• Greenhouse gases absorb infrared radiation, emitted by the Earth’s surface, the atmosphere and clouds• The net result is an upward transfer of infrared radiation from warmer levels near the Earth’s surface to colder levels at higher altitudes.• The natural greenhouse effect is part of the energy balance of the Earth• Clouds also play an important role in the Earth’s energy balance and in particular in the natural greenhouse effect. 03/20/13 44
  43. 43. Weather• Weather is the fluctuating state of the atmosphere around us, characterized by the temperature, wind, precipitation, clouds and other weather elements.03/20/13 45
  44. 44. Human activities• Combustion of fossil fuels , biomass burning, produce greenhouse gases and aerosols• Chlorofluorocarbons (CFCs) and other chlorine and• bromine compounds has an impact on the radiative forcing and has led to the depletion of the stratospheric ozone layer.• Land-use change, Urbanization, human forestry, agricultural practices• Affect the physical and biological properties of the Earth’s surface.• Change the radiative forcing and have a potential impact on regional and global climate 03/20/13 46
  45. 45. IPCC• The Intergovernmental Panel on Climate Change (IPCC) : – International body for the assessment of climate change. – It was established by the United Nations Environment Programme (UNEP) and the World Meteorological Organization – Provide view on the current state of knowledge in climate change and its potential environmental and socio- economic impacts. – It reviews and assesses the most recent scientific, technical and socio-economic information produced worldwide relevant to the understanding of climate change. – It does not conduct any research nor does it monitor climate related data or parameters.03/20/13 47
  46. 46. IPCC working groupThe IPCC has three Working Groups and a Task Force• Working Group I : Assesses the scientific aspects of the climate system and climate change.• Working Group II: Addresses the vulnerability of socioeconomic and natural systems to climate change, the resultant negative and positive impacts of climate change and the options for adaptations to lessen the impacts.• Working Group III: Assesses options for limiting greenhouse gas emissions and otherwise mitigating climate change.• The Task Force on National Greenhouse Gas Inventories defines and disseminates standardized methods for countries to calculate and report GHG emissions.03/20/13 48
  47. 47. controlPreventive: anticipate, prevent or minimize the causes of climate change and mitigate its adverse effects• For the benefit of present and future generations of humankind on the basis of equity• Equitably meet developmental and environmental needs of present and future generations
  48. 48. References• 1. A.J. McMichael., D.H. Campbell-Lendrum., C.F. Corvalán., K.L. Ebi., A.K. Githeko., J.D. Scheraga., A. Woodward (2003). Climate change and human health : Risks And Responses WHO, GENEVA• 2. A.P.M. Baede ., E. Ahlonsou., Y. Ding., D. Schimel., B. Bolin, S. Pollonais (-). The Climate System: an Overview03/20/13 50