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The Threat of Dengue Fever - Assessment of Impacts and Adaptation to Climate Change in Human Health in the Caribbean An AIACC Project at The University.

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Presentation on theme: "The Threat of Dengue Fever - Assessment of Impacts and Adaptation to Climate Change in Human Health in the Caribbean An AIACC Project at The University."— Presentation transcript:



3 The Threat of Dengue Fever - Assessment of Impacts and Adaptation to Climate Change in Human Health in the Caribbean An AIACC Project at The University of the West Indies, Mona and Caribbean Epidemiology Centre

4 Dengue in the Caribbean and El Nino years and year after an El Nino - El Nino +1 El Nino El Nino + 1

5 The Culprit (Vector) Also the dengue mosquito

6 The Problem The water problem: In times of rain, pools of water collect in providing breeding habitats. The water storage problem In dry periods, water is stored in open containers which provide breeding habitats

7 The Temperature Problem: The extrinsic incubation period (EIP) (period of incubation of parasite inside the vector) shortens at higher temperature Focks et al (1995) - dengue type 2 has an EIP of 12 days at 30 ○ C but only 7 days at 32-35 ○ C. Koopman et al. (1991) - decreasing the incubation period by 5 days can lead to a threefold higher transmission rate of dengue.

8 The Temperature Problem (Cont.): Higher temperatures increase the amount of feeding and the probability of dengue transmission to new hosts. Moderately high temperatures hasten the larval stage, leading to smaller mosquitoes, which then require more frequent blood meal. Increased temperature also enhance metabolism.

9 The El Nino Problem: Taylor (1999) - El Niño years in the Caribbean produce drier than normal conditions in the latter half of the year Drying tendancy was also reported by others, including Ropelewski and Halpart (1996) nThe above leads to the storing of water problem The air temperature increases during El Niño conditions in the Caribbean (Malmgren et al, 1998). nThis leads to the temperature problem. Chen et al (1997), Taylor (1999), Chen and Taylor (2001) showed how rainfall and temperature increases during May to July in the El Niño + 1 year nThis leads to the temperature and water problem.

10 The Climate Change Problem: Santer (2001): mean temperature increase of up to 2ºC is projected for Caribbean after 70 years of CO 2 doubling. Expected modulation of temperature by future El Niño events will further enhance above increase periodically. Timmermann et al (1999) found an increase in El Niño frequency in a climate model forced by future greenhouse warming. nAll the above lead to the temperature problem IPCC (1998): likely alteration of the global distribution of dengue due to climate change, with 2.5 billion at risk in the tropics and sub tropics.

11 The Project The Threat of Dengue Fever AIACC in Human Health in the Caribbean Objectives: to determine the extent of the association between climate and the incidence of dengue across the Caribbean region; to identify and evaluate adaptive options to ameliorate the impact of climate on this disease; to use the knowledge gained above to determine future impacts (long term - next 50 -100 yrs) and adaptation based on global change scenarios; to make the knowledge gained accessible and useful to decision makers.

12 Co-Principal Investigators: A. Anthony Chen, Atmospheric Physicist Dept of Physics, University of the West Indies (UWI), Mona,Jamaica Samuel C. Rawlins, Entomologist/Parasitologist Caribbean Epidemiology Centre (CAREC),Trinidad & Tobago Responsible Institution: UWI, Mona UWI Team: A. Dharmeratne Amarakoon, Physicist Wilma Bailey, Health Geographer Albert Owino, Meteorologist Michael A. Taylor, Meteorologist CAREC Team: Karen Polson, Epidemiologist

13 Others Dave Chadee, Ministry of Health, T&T and UWI Department of Life Science, St. Augustine Rohit Doon, Ministry of Health, T&T Karen Webster, Sherine Huntley, Ministry of Health, Ja.

14 Post Graduate Students Rainaldo Crosbourne, Data base management Charmaine Heslop-Thomas, Medical Geography Cassandra Rhoden, Scenario generation Roxann Stennett, Impact Studies

15 Consultants: Dr. Joan L. Aron 1, Science Communication Studies Prof. Ulisses E.C. Confalonieri 2, Fundacao Oswaldo Cruz Dr. Henry F. Diaz 3, NOAA/CDC Dr. Roger Pulwarty 3, NOAA Dr. Benjamin D. Santer 4, Lawrence Livermore National Laboratory Dr. Neil Ward 5, International Research Institute Dr. Tom Wigley 5, National Center for Atmospheric Research Dr. Rob L. Wilby 5, King’s College, London 1. Mathematical Modeller, 2.Epidemiologist, 3. Climatologist 4. Atmospheric Physicist, 5. Climate Modeller

16 Methodology in Epidemiology Development of historical epidemiology database managed by CAREC and collection of current Dengue/ dengue haemorrhagic fever (DHF) data. Retrospective studies of the disease in the last 15 years past climate association with dengue fever Prospective studies carried out in the first two and half years of the project on Vector abundance, climate and dengue occurrence.

17 Methodology in Climate: Development of climate database managed by CSGM and collection of current data Generating future climate change scenarios. >Using statistical downscaling techniques to regionalize climate change projections from global climate models (GCM’s) that use Special Report Emission Scenarios (SRES) as inputs > PC-based Statistical Downscaling Model (SDSM) [Wilby et al, 2001],

18 Assessment of Impact and Adaptation Strategies Socio-economic study  identify the socio-economic groups most at- risk for infection;  estimate the ability to respond Knowledge, Attitude and Practices (KAP) survey  population's perception of climate change impacting on dengue;  readiness of the community to modify vector production behaviour, based on the forecast of conditions favourable to vector and disease increase.

19 Recommendations for Adaptation Analysis of adaptation strategies based on impact and scenario studies Early warning system

20 Results: Retrospective Study



23 Moving Average Temperature (MAT) = T N is the average temperature during the N th 4 week period or month M = 1, 2, 3,…13 or 12. Examples: For 1 st 4 week period or 1 st month, M=1 and For 2 nd period or month, M=2 and For 4 th period or month M= 4 and


25 Results: Prospective Study

26 Results: Socio-economic Study


28 Results: KAP Survey

29 Results: Scenario generation: Ja. Temperature

30 Scenario generation: Barbados Precip

31 Consequences Increase in temperature of about 2ºC expected by 2080 Not much change in precipitation expected 2ºC is expected to give rise to a 3- fold increase in the rate of transmission of dengue

32 Early Warning using MAT index: Avg MAT Early crossing of Avg. MAT in 1998 associated with early onset; slow approach in 1997 assocated with late onset; crossing in 1996 and 2000 coincides with onset

33 Early Warning System for Dengue Epidemic Check List:  Climate Surveillance  MAT index  Epidemiology Control (Surveillance)  Breteau index  Pupae/person Index  Presence of dengue below epidemic level  Response within means

34 MAT The time the average MAT is approached or reached can be used to gauge the potential for the onset of an epidemic –An analog approach can be used Especially useful for timing early or late epidemic Easiest of items on check list to monitor Next step – remaining items on check list

35 Adaptation: Short and long term measures

36 Weighting Low - 1, Medium -2 High – 3 Reversed for Cost and Technical Challenge Assignment based on expert opinion (MOH’s)


38 Climate Change and biodiversity How will climate change?

39 IPCC: The World Meteorological Organization (WMO) and the United Nations Environment Programme (UNEP) established the Intergovernmental Panel on Climate Change (IPCC) in 1988.. The 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 assesses the vulnerability of socio- economic and natural systems to climate change, negative and positive consequences of climate change, and options for adapting to it. Working Group III assesses options for limiting greenhouse gas emissions and otherwise mitigating climate change.Working Group IWorking Group IIWorking Group III

40 Summary for Policy Makers (Global Projections Working Group 1) FINAL FIGURES & TABLES FROM PLENARY Updated: 20 Feb 2007

41 Conclusions about projected climate change for Caribbean region: Sea levels will likely continue to rise on average during the century around the islands of the Caribbean Sea. (Models indicate that the rise will not be geographically uniform globally but large deviations among models make estimates of distribution across the Caribbean, Indian and Pacific Oceans uncertain.) All Caribbean islands are very likely to warm during this century. The warming is likely to be somewhat smaller than the global, annual mean warming in all seasons. Rainfall in the vicinity of the Greater Antilles is likely to decrease in JJA but changes elsewhere and in DJF are uncertain.

42 For More details Climate Change Conference at UWI June

43 Climate Change and Biodiversity

44 Some topics in biodiversity Loss of habitat Shift in Ecological Zones Erosion of beaches Inundation of coastal lands Cost to protect coastal community Fisheries Declining area for turtle nesting Change in forestation Forest Health and productivity Carbon sequestration Modelling Adaptation

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