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Amazon Malaria Initiative / Amazon Network for the Surveillance of Anti-malarial Drug Resistance

Amazon Malaria Initiative / Amazon Network for the Surveillance of Anti-malarial Drug Resistance Bogota, Colombia, March 17–19, 2009 “Climate Change and Malaria” or Climate Risk Management in Health Stephen Connor, International Research Institute for Climate & Society (IRI),

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Amazon Malaria Initiative / Amazon Network for the Surveillance of Anti-malarial Drug Resistance

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  1. Amazon Malaria Initiative / Amazon Network for the Surveillance of Anti-malarial Drug Resistance Bogota, Colombia, March 17–19, 2009 “Climate Change and Malaria” or Climate Risk Management in Health Stephen Connor, International Research Institute for Climate & Society (IRI), The Earth Institute at Columbia University, New York . PAHO/WHO Collaborating Centre on early warning systems for malaria and other climate sensitive diseases

  2. how can we get the knowledge benefit from recent advances in climate science and observation Into climate sensitive development sectors… …to more effectively manage the associated risks affecting vulnerable populations? …sooner rather than later … (e.g. MDG timeframe 2015)

  3. Climate Change…… ^T 0.74ºC circa 100 years

  4. And rainfall circa 100 years? Long term trend: 18% Variance Inter-decadal variability: 27% Variance Inter-annual variability: 55% Variance • Example: observed rainfall variability in the Sahel 1900-2006. • long-term variability (linear trend), • decadal variability (after removing the linear trend) • inter-annual variability (after removing the linear and decadal trends)

  5. Malaria has also changed greatly in the past 100 years…. Malar ia T i m e Americas: USA – malaria declined as a result of changes in land use and ‘eradication’ which was declared in 1949 – occasional ‘import’ malaria Guyana 1940s: 40,000 cases/1965: 22 cases/1994 84,017 cases – down again today Europe: decline as a result of land use change/eradication – some resurgence >WWII. Eradication declared during 1950s and 1960s – occasional ‘import’ malaria Asia: India 1940s:circa 70 million cases/late 1950s circa 100,000/1970s >20 million Sri Lanka – 1940s: circa 2 million case/1963 17 cases/1967-68 massive resurgence – but down again today Africa: Not included in the Global Eradication Campaign – though notable examples e.g. Swaziland 0 cases in 1972 - resurgence 1978 on – but down again today

  6. Clearly its more complex…multi faceted… Malaria vs poverty

  7. So does climate have a role to play ? Climate may impact on health through a number of mechanisms • directly through cold or heat stress – aggravating conditions such as heart disease and respiratory conditions, - and indirectly, for example through: a) food security - nutritional status and immuno-suppression, b) water source quality and water-borne disease c) infectious diseases – malaria being a good example

  8. Where (CS) disease is not adequately controlled …. Then climate information is relevant to informing on: • Seasonality in endemic disease • Shifts in the spatial distribution of endemic and epidemic disease • Changes in risk of epidemic disease > Epidemic Early Warning Systems

  9. Climate and infectious disease …… Using Climate to Predict Infectious Disease Epidemics. WHO 2005 .. bacterial, viral and protozoan .. ..other candidates, e.g some respiratory diseases not included here…. … must remember socio economic factors very important…

  10. Demand for integrated early warning systems … Climate Env-Info Integrated MEWS gathering cumulative evidence for early and focused epidemic preparedness and response (WHO 2004) Monitoring and Surveillance

  11. Demands for evidence-based health policy Before using climate information in routine decision making health policy advisors need: Evidence of the impact of climate variability on their specific outcome of interest, and Evidence that the information can be practically useful within their decision frameworks, and Evidence that using climate information is a cost-effective means to improving health outcomes. …. A case study >>>>

  12. An example: Malaria and MEWS in Botswana Policy Changes Botswana straddles the southern margins of malaria transmission in sub-Saharan Africa. The incidence of malaria varies considerably from district to district across the country – showing a general north-south decreasing pattern from more stable to less stable malaria. In Botswana the incidence of malaria also varies considerably from year to year – and as such malaria is considered to be ‘unstable’ and prone to periodic epidemics (MoH 1999)

  13. Vulnerability monitoring Example in practice: Botswana … Routine assessment of drug efficacy in sentinel sites, susceptibility of the vector to insecticides, coverage of IRS achieved each season Regular assessment of drought-food security status from SADC Drought Monitoring Centre - disseminates the information to the epidemic prone DHTs Recognises need for extra vigilance among its most vulnerable groups, including those co-infected with HIV, TB, etc.

  14. Seasonal Climate Forecasting Example in Botswana ….. SCF offers good opportunities for planning and preparedness. NMCP strengthens vector control measures and prepares emergency containers with mobile treatment centres Lead-time 5 months Evidence of impact of climate variability on specific outcome of interest (Thomson, et al. Nature. 2006)

  15. Environmental monitoring Example in Botswana …ENV monitoring enables opportunities to focus and mobilise more localised response, i.e. vector control and location of emergency treatment centres…. Lead-time 1 to 2 months Evidence of impact of climate variability on specific outcome of interest (Thomson, et al. AJTMH. 2005) Adjusted malaria anomalies

  16. Case surveillance Threshold 1-600 unconfirmed cases/week >>> Action Plan 1. Threshold 2-1000 unconfirmed cases/week >>> Action Plan 2. Threshold 3-3000 unconfirmed cases/week >>> Action Plan 3. Example in Botswana .. Of a number of indicators (WHO 2004) the NMCP uses case thresholds defined for three levels of alert …

  17. RBM: Southern African Regional MEWS activities Evidence for practical application within a decision making framework (DaSilva, et al. MJ 2004). Evidence for using environmental monitoring (Thomson, et al. AJTMH 2005) Evidence for using seasonal forecasting (Thomson, et al. Nature 2006). Evidence of timing/effectiveness (Worrall, et al. TMIH 2007; Worrall, et al. 2008)

  18. 2005-06 The 2005/06 season in Southern Africa….. A ‘test case’ for MEWS in the Southern Africa region A ‘wet year’ following three ‘drought’ years (like 96/97) when major regional epidemics had occurred “Classic post-drought epidemics” have occurred periodically in Southern Africa’s history

  19. Demonstrated progress…..

  20. And for application of the approach elsewhere ? .. growing interest/demand from other countries/regions: in West Africa (malaria and meningitis) in South East Asia (malaria, dengue and respiratory) in Colombia (malaria & dengue) in East Africa (malaria, meningitis cholera & RVF)

  21. Climate Risk Management for Health Clearly we must take steps to mitigate Climate Change. However…… learning to manage climate risk on a year to year basis is undoubtedly our best method of adapting to climate change A society that manages current climate risks – is less vulnerable - more resilient – giving it greater adaptive capacity to face the many risks associated with climate change.

  22. Need to: Improve understanding of climate-environment-disease-interaction …. to build knowledge base for risk management Invest in effective control now & face the future with lower disease burden Develop “more broadly informed surveillance systems” to sustain advances in control and ultimately elimination/eradication

  23. PAHO/WHO Collaborating Centre on early warning systems for malaria and climate sensitive diseases Thank you for your attention sjconnor@iri.columbia.edu

  24. e.g. Seasonal climate and endemic malaria …. Temporal information useful for developing seasonal disease calendars for control planning purposes Due to poor epidemiological data in sub-Saharan Africa - climate data often used to help model and map the distribution of disease. Climate suitability for endemic malaria = 18-32ºC + 80mm + RH>60%

  25. e.g. the impact of climate trends…. 30 year drought >? Changes in malaria <endemicity (Faye et al 1995) Changes in meningitis >southward extension of ‘Meningitis Belt’ >epidemic frequency (Molesworth et al 2003) Very important consideration when establishing baselines

  26. e.g. Climate anomalies and epidemic malaria …. Desert fringe malaria … e.g. Botswana

  27. But - what is an epidemic? • More cases than expected at a particular place and time ? • Where R0 temporarily goes above 1 ? • ‘True epidemics’ – infrequent (possibly cyclical) events in areas where the disease does not normally occur – e.g. warm arid/semi arid zones and beyond the highland-fringe. • Unusually high peak in seasonal transmission • Neglect/breakdown of control – ‘resurgent outbreaks’ with subsequent increase in endemicity level • Epidemics in complex emergencies – transmission exacerbated by population movement and political instability – may include the above – and may be ‘triggered’ by a climate anomaly • introduction of exotic vector (? rare ?)

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