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

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. Invited lecture FELTPK Residents during the “One Health Week
The Field Epidemiology and Laboratory Training Programme (FELTPK) in Kenya is a two-year postgraduate competency
based training program in applied epidemiology and public health laboratory management. It was established in April 2004
to enable frontline public health professionals acquire the latest knowledge and skills that address global threats to public
health, 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) in
Applied Epidemiology or Msc in Laboratory Management and Epidemiology from Jomo Kenyatta University
of Agriculture and Technology (JKUAT). Other key collaborating partners include Kenya Medical Research
Institute (KEMRI), Ministry of Medical Services and Ministry of Public Health and Sanitation, Ministry of
Livestock Development, World Health Organization (WHO), World Bank and the African Field Epidemiology
Network (AFENET).
Following the need to strengthen "One Health" initiatives in Kenya, FELTPK enrolled four (4) veterinary
officers from the Ministry of Livestock Development this academic year. This was followed by designing a one
health 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 Samuel
Amwayi.

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. 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. Key concept
One world – one health
Gaia
Hypothesis 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. 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. 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. 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. 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. 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. Climate change in drylands
CENTRAL ASIA
Temp: +3.7 C
Rain: -3%
Drought yrs: +12%
SAHARA
Temp: +3.6 C
Rain: -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. • Livestock:9- 18% anthropogenic
emissions
• 80% agricultural emissions
Contributors
to climate
change

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. Warmer, wetter, wider variation
→ sicker?
Warmer Wetter / (drier) Wider
variation
D ↑ growth rate ↑ ↓ Survival in air Post disaster
↓ generation time ↑ Faecal-oral disease
↑ ↓ survival transmission Endemic instability
↑ season ↑ Movement in water Spread/shrinkage
↑ activity
I Wildfires Change farming systems
Air Pollution (O3, PM, GHG) Population movements
Nuisance Plants Increase in biomass
More intense air movement Change trade patterns

15. Group work:
What important diseases in Kenya
may be climate sensitive

16. Conceptualising CSD
Vector-borne Malaria, dengue, WNV, Shifting distribution of vectors
disease RVF, TBE, Lyme, Higher temperatures affect vectorial capacity and
leishmaniasis, feeding frequency
trypanosomosis, Drought & heavy rain leads to population surges
schistosomiasis,
onchocerciasis
Water associated Cholera, Disaster and lack of sanitation
cryptosporidiosis, Flooding and run-off
leptospirosis Higher water temperature
Food borne Salmonella, E. coli, Lack of sanitation
Campy, Listeria
Air borne Meningitis, Q fever Higher RH allows survival
(FMD) Dust
Soil associated Anthrax Temperature, RH and soil moisture affect spore
Clostridial disease germination
Heavy rainfall stirs up dormant spores
Rodent borne Hanta virus; Lasa
fever virus
Multistage Fascioliasis Conditions favour intermediate hosts
parasites

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
adaptation
Source: Climate Change and Human Health – Risks and Reponses. Summary (WHO, 2003)

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 fomites
intermediate and amplifier hosts •Animal owners
•Domestic livestock
•Rural dwellers
•Wildlife
•Consumers of animal foods
•Companion animals
More extreme events Raising sea levels Increased temperature, Regional shifts in climate
increased precipitation envelopes

20. Annual human deaths early 21st century
All infectious 18,000,000
Diarrhoea (50% zoonotic) 3,000,000
Road traffic 1,200,000
Leptospirosis 123,000 & pig/dairy production
Cysticercosis 50,000 & pig production
Extreme weather related 20,000
Predicted climate change 150,000
Malaria 1,000,000
Dengue 20,000
Sleeping sickness 50,000 & exclusion farming & production
Leishmaniasis 47,000 & companion animal
Q fever 3,000 & sheep, goat, dairy production, emerging
Lyme disease 2,000 & emerging
West Nile fever 100 & equine losses, emerging
Rift valley fever 45 & sheep production, trade, emerging
Emerging disease ???? 20

21. Drivers of change
GNDP

22. 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

23. 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

24. 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

25. 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

26. 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).

27. 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

29. 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 journal
Distribution of A. arabiensis

30. HAT in Africa
A= current geographical range suitable for T. b. rhodesience B= A2 climate change scenario 2055
SEIR model and IPCC data
Range increases by 10%; considerable shifts – foci in Ethiopia disappear
Moore et al 2012; J. R. Soc Interface

31. Anthrax in Kazakhstan
A= current scenario
B= A2 scenario (drastic)
C= B2 scenario (milder)
IPCC & historical anthrax
datasets; GARP model
Joyner et al, 2010, PLOS 1

32. Malaria
VERY
HIGH
RVF
Cholera Meningitis
HIGH
Climate 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

33. Which CSD are most important to the
poverty/ls nexus: the big five
Animal 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

34. 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

35. 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

36. 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

37. 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

38. 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

39. conflict
Large-scale
population milieu for catastrophic
dislocation emerging diseases, e.g.
multi-drug –resistant TB,
artemisinin-resistant
failing malaria, HIV, others
governance
Sea 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

40. Less
conflict
Improved
public
health
Less
climate
Improved Better global education and
change
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 energy
technologies, especially solar
Butler, in press (2012)

41. 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
• http://www.ipcc.ch/
• http://www.who.int/topics/climate/en/
03/20/13 Climate and health
41

42. 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 longer
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43. 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
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44. 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
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45. Weather
• Weather is the fluctuating state of the
atmosphere around us, characterized by the
temperature, wind, precipitation, clouds and
other weather elements.
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46. 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
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47. 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.
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48. IPCC working group
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: 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.
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49. control
Preventive: 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

50. 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 Overview
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