Climate Change and Evolution of Vector Associated Pathogens: Potential ti lto increase or decrease duration and intensity of epidemics

Transcription

1 Climate Change and Evolution of Vector Associated Pathogens: Potential ti lto increase or decrease duration and intensity of epidemics Impact of Climate Change on Infectious Diseases and human Health Impacts of Climate Change on Infectious Diseases Annecy, Les Pensieres, France, November 2008 Kenneth J. Linthicum Center Director Center for Medical Agricultural and Veterinary Entomology USDA-ARS Gainesville, Florida

2 Collaborators Assaf Anyamba; Jennifer Small; Ed Pak; Compton J. Tucker» Goddard Space Flight Center, Biospheric Sciences Branch, Greenbelt MD Jean-Paul Chretien» Department of Defense Global Emerging Infections Surveillance & Response System, Division of Preventive Medicine, Walter Reed Army Institute of Research, Silver Spring MD David Schnabel (current); Sheryl Bedno (previous); Jason Richardson (previous)» US Army Medical Research Unit Kenya, Nairobi Kenya Seth Britch and Jerome Hogsette» Center for Medical, Agricultural & Veterinary Entomology, USDA-ARS ARS, Gainesville, Florida

3 President Kennedy Stated on 10 June 1963 in reference to the world community: For, in the final analysis, our most basic common link is we all inhabit this planet. We all breathe the same air.

4 Urbanization changes the landscape and surrounding ecosystems: Impacting climate, interactions between vectors/animals/people and ultimately vector-borne diseases and their control

5 Earth s oceans serve as the engine of the earth s climate/ecosystems and they are closely linked

6 El Niño/Southern Oscillation (ENSO): global climate affects local climate

7 Hypothesis of Presentation Climate change/variability directly affects:» The spatial and temporal distribution of mosquito vector species and the diseases they transmit to animals and humans

8 Overview of Argument 1. Examples of how climate change/variability affects the ecology of vectors/vector-borne t diseases 2. Example of how coupling of the ecology of vectors/ vector-borne disease and global climate change/variability knowledge can permit disease forecasting

9 1. Climate change/variability affect on ecology of vectors/vector-borne diseases A. Temperature Affect on Aedes aegypti to transmit dengue virus in Southeast Asia Affect on Ae. aegypti / chikungunya virus in Africa B. Rainfall Affect on Aedes and Culex to transmit Rift Valley fever in sub-saharan Africa

10 1A. Temperature Aedes aegypti mosquitoes transmit dengue virus Dengue virus infection produces classical dengue, DHF and DSS In Southeast Asia dengue is hyperendemic DHF is reported, classic dengue is not

11 Aedes aegypti 1A. Temperature Vectorial competence is dependent d upon the Extrinsic incubation (EI) period EI = time from virus ingestion to virus in Salivary Gland Shorter EI period (higher ambient temperature) = greater vectorial competence Time Dengue Infected midgut Uninfected midgut Infected Salivary Gland

12 1A. Temperature Outgoing Longwave Radiation (OLR) data acquired by NOAA satellites Cool and dwet Warm and Dry OLR Anomaly = yearly value - 20 yr. mean value divided by the SD of mean OLR indirectly assesses climate over land surface) (blue = rain; red = dry and hot)

13 Burma Thailand

14 Burma and Thailand OLR (Dry and Hot) Positively correlated with DHF OLR with DHF Incidence Anomaly 1.0 Cross Correlatio on Function % Confidence Limit -1.0 Coefficient Lag Number Transforms: difference (1)

15 Dengue Summary Hot -dry periods precede elevated DHF Elevated DHF is likely the result of short Extrinsic Incubation period in mosquito Figure Three: Seasonal D istribution of Serologically C onfirm ed D engue C ases at B angkok C h ild re n 's H o sp ita l fro m Hot-Dry 200 Cases / 1974 / 1975 / 1976 / 1977 / 1978 / 1979 / 1980 / 1981 / 1982 / 1983 / 1984 / 1985 / 1986 / 1987 / 1988 / 1989 / 1990 / 1991 / 1992 / 1993 / 1994 / 1995 / 1996 / 1997 / 1998 / Y e a r

16 A. Temperature (cont) Affect on Aedes aegypti to transmit chikungunya virus in Africa Linkages Between Global Climate Indicators and chikungunya transmission in Indian Ocean/East Africa

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18 Current Chikungunya (CHIK) Outbreak Starts in June 2004 in Lamu, Kenya Virus similar to viruses circulating previously in West, East and South Africa Largest CHIK outbreak on record > 200,000 cases in La Reunion > 200, (63%) in Comoros, 13,000 in Lamu (75%)

19 Lamu June 2004

20 OLR Anomalies, Jan-Jun 2004 Jan Jan Feb Feb Mar Mar Jun Apr May Apr May Jun Lamu outbreak

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22 NDVI and Rainfall (Lamu), Chretien, Anyamba, Bedno, Breiman, Sang, Sergon, Powers, Onyango, Small, Tucker, Linthicum. Am J Trop Med Hyg 2007;76:405. Lamu Outbreak

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24 Chikungunya Outbreak in Italy, 2007 Rezza et al. Lancet 2007;370:1840.

25 Chikungunya Outbreak in Italy, 2007

26 1B. Rainfall Affect on Aedes and Culex mosquitoes to transmit Rift Valley fever (RVF) in sub-saharan Africa Linkages Between Global Climate Indicators and Rift Valley fever Transmission

27 ENVIRONMENT, HABITAT CONDITIONS AND EVOLUTION DYNAMICS Outbreaks of RVF are known to follow periods of widespread d and heavy rainfall associated with the development of a strong inter-tropical convergence zone over Eastern Africa Rai infall x Rainy Days RVF Epizootics Davies et al. Bull. WHO

28 Vector Dynamics and Ecology Emergence and population expansion of a number of disease vectors (mosquitoes, mice, locust) often tends to follow the trajectory of the green flush of vegetation in semi-arid lands Dry Wet cycles appear to maintain the virus cycle through time NDVI data can therefore be used as a multipurpose indicator of conditions associated with vector-borne disease outbreaks in support of disease surveillance activities

29 Reconstruction of RVF Outbreak History in East Africa

30 First Conclusion Climate change/variability directly affects ecology of vectors and vector-borne disease transmission

31 2. Coupling of the ecology of vectors/ vector-borne disease and global climate change/variability can permit disease forecasting El Niño/Southern Oscillation (ENSO) is the most well known phenomenon influencing Global climate variability El Niño refers to large-scale ocean- atmosphere climate phenomenon linked to periodic warming in sea surface temperatures across central equatorial Pacific The large size of the Pacific Ocean changes sea surface temperature patterns and gradients across the basin and influence atmospheric circulation El Niño conditions has pronounced impact global tropical precipitation extending into the northern hemisphere, particularly North America Climate variability has a demonstrated impact on infectious disease pathogen vector - host interactions

32 Operational Application: Rift Valley fever Outbreak Convergence of Pacific El Nino event and WIO Warming Wide spread, persistent and rainfall in semi arid lands Flooded dambos hatching of infected mosquito eggs, supports several generations of mosquito populations Vegetation green-up micro-ecological habitats conducive to mosquito survival and propagation First human cases identified late December 1997, declared Epizootic late January 1998 Impact on Livestock Trade: Ban on livestock imports from GHA loss of income ~ $ 100 million in 1998 Reported losses of ~70% sheep and goats and 20%-30% ~ cattle and camels estimated 89,000 humans in this region could have been infected (North Eastern Kenya and central Somalia)

33 Operational Application Persistence mapping of above normal vegetation conditions

34 SST Time Series Concurrent elevation in Pacific & Indian SST in Sept 2006

35 Hotspots of potential elevated risk for disease outbreaks under El Niño conditions: HOTSPOTS OF POTENTIAL ELEVATED RISK TO DISEASE OUTBREAKS UNDER EL NIÑO CONDITIONS: HPS, PL MAL DENG RI MAL CHOL RVF CHOL DENG RI DENG Dengue Fever RI Respiratory Iliness CHOL Cholera MAL Malaria RVF Rift Valley Fever HPS Hanta Virus Pulmonary Syndrome PL Plague International Journal of Health Geographics com/content/5/1/60

36 Situation: November 2006 Global Climate Indicators

37 Seasonal Summary: SST, OLR SON 2006

38 Seasonal Summary: Rainfall SON 2006

39 NDVI Anomalies: Sept, Nov 2006

40 RVF Potential : Sept, Nov 2006

41 Action: Sept Nov 06 Warning issued in Emerging g Disease paper presented at Society of Vector Ecology Plenary Session, Anchorage, Alaska Issued First Alert Mid-October Wrote GEIS Advisory distributed to DoD Overseas Laboratory Network Global Elevated Risk of Outbreaks of Vector-borne diseases, and to WHO, FAO Advisory submitted to International ti Journal of Health Geographics

42 Action: Nov Early Dec 06 Issued Second Alert Early-November Presented at the WHO Joint Intercountry Workshop on Crimean-Congo Haemorrhagic Fever (CCHF) Prevention and Control Istanbul, Turkey, 6-8 November 2006 Published on FAO Emergency Prevention System (EMPRES) for Transboundary Animal and Plant Pests and Diseases EMPRES WATCH website: Possible RVF activity it in the Horn of Africa Information transmitted to FAO country and regional offices Forecast Reported in various global media outlets AP, Washington Post, Chicago Tribune, NYT, Nation-Kenya etc Warning presented at RVF Federal Agency Workshop in Ft. Collins, Colorado, early December USAMRU-K/GEIS-Kenya Entomology Team mobilized resources and personnel for field deployment mosquito collections and analysis.

43 FAO Alert issued November 2006

44 January 2007 RVF Risk Geographic Extent USAMRU/GEIS-K Mosquito samplings sites

45 Rift Valley fever Chikungunya fever Climatic factors Flooding Warm, dry conditions Biological factors Broad host and vector range Abundant livestock host Genetic adaptation to Aedes albopictus &A Aedes aegypti to humans Physical Dambos, other Vector breeding environment ground pools sites factors Social,,political Livestock trade Travel and economic factors Herder and religious practices Delayed notification and control Previous introduction of Aedes albopictus to Indian Ocean islands and Italy by Trade

46 Vector-borne Disease Climate Link Building evidence suggests links between El Niño/Southern Oscillation (ENSO) driven climate anomalies and infectious diseases, particularly those transmitted by arthropods:» Murray Valley encephalitis (Nicholls 1986)» Bluetongue (Baylis et al. 1999)» RVF (Linthicum et al. 1999)» African Horse Sickness (Baylis et al 1999)» Ross River virus (Woodruff et al. 2002)» Dengue (Linthicum et al IOM publication)» Malaria (Bouma & Dye 1996)» Chikungunya (Chretien et al. 2006)

47 Conclusions Threat from globalization of various arboviruses, like dengue, chikungunya and RVF, is real and ever present danger The development of El Niño conditions has significant implications for global public health Surveillance and control preparations are critical Extremes in climate events with above normal rainfall and flooding in some regions and drought periods in other regions occurred

48 Conclusion (continued) Understanding the impact of Climate on the Ecology of vector-borne disease transmission is critical, and the more it is understood the more it can provide public health authorities with ability to:» Design better containment or exclusion strategies to limit disease spread» Target disease surveillance/control efforts» Minimize cost of surveillance over large areas» Forecast Risk and permit anticipation i of globalization li of vector-borne disease

49 Contributors Kenneth J. Linthicum and Seth Britch, Center for Medical, Agricultural & Veterinary Entomology, Agricultural l Research Service, United States t Department t of fagriculture, Gainesville, Florida. Assaf Anyamba, Jennifer Small & Compton J. Tucker, NASA/Goddard Space Flight Center, Biospheric Sciences Branch, Code 614.4, GIMMS Group, Greenbelt, Maryland. Jean-Paul Chretien - Department of Defense, Global emerging Infections System, Division of Preventive Medicine, Walter Reed Army Institute of Research, Washington, DC. International Research Institute for Climate Prediction (IRI), Columbia University, New York NOAA Climate Prediction Center, Camp Springs, Maryland. USDA Foreign Agricultural Service (FAS), Washington D.C. Collaborators Department t of Defense, Global l Emerging Infections Surveillance & Response System (DoD-GEIS), Division of Preventive Medicine, Walther Reed Army Institute of Research, Washington, DC World Health Organization Pandemic Alert and Response Department, Geneva Food and Agricultural Organization (FAO), Rome.

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54 For Example: Air Curtain in Jet Ways Keep Infected Vectors in Aircraft Until Control