Effects Of Climate Change On Health Dr Troy Gepte National Grassroots Conference on Climate Change Balai Kalinaw, UP Diliman 20-21 April 2009 www.philclimatewatch.org

1. Effects of Climate Change
on Health
Dr. Troy D. Gepte

2. Coverage of Presentation
• Overview of the Effects of Climate Change on
Health:
– Temperature-related and Weather-related effects
– Natural Disasters due to extreme climate/weather
events
– Other likely health impacts
• Emerging and Re-emerging
Infections and their Impact on Public Health

3. Health effects
Health Effects
Temperature-related
illness and death
Extreme weather-
Extreme weather-
related (floods, storms,
related health effects
etc.) health effects
Human
Air pollution-related
exposures health effects
Regional weather
Water and food-borne
Climate changes
diseases
Change
•Heat waves
Vector borne and
•Extreme weather
rodent borne diseases
•Temperature
•
•Precipitation
•Sea-level rise

4. Why are these important?
• These disruptive events have their greatest
impact in poor countries.
• The two categories of climatic extremes are:
– Simple extremes of very low or very high
temperatures
– Complex events: droughts, floods, or
hurricanes

5. Deadly effects
• Extremes of temperature can kill
– The very old, the very young and the frail
are most susceptible
• There will be more intense heatwaves
– as well as warmer summers and milder
winters
– effects of weather will vary between
populations

6. Source: WHO

7. Natural Disasters
• Increasing trend in the number of victims due to
natural disasters is:
– partly due to better reporting
– partly due to increasing population vulnerability, and
– may include a contribution from ongoing global
climate change
• Developing countries are poorly equipped to
deal with weather extremes
– especially in high-risk areas (coastal zones &cities)
– Number of people killed, injured or made homeless
by natural disasters is increasing rapidly

8. Source: WHO

9. Additional likely health impacts
that are hard to assess:
• changes in air pollution and aeroallergen levels
• altered transmission of other infectious diseases
• effects on food production via climatic influences on
plant pests and diseases
• drought and famine
• population displacement due to natural disasters,
crop failure, water shortages
• destruction of health infrastructure in natural
disasters
• conflict over natural resources
• direct impacts of heat and cold (morbidity)

10. Patterns of Infectious Diseases
are expected to change
• Climatic factors are related to vector-borne
diseases, many enteric illnesses and certain
water-related diseases.
• With climate change, we will have a tougher
fight against infectious diseases.
• This is most evident in areas where climate
variations are marked and especially in
vulnerable populations.

11. Health effects
Health Effects
Temperature-related
illness and death
Extreme weather-
Extreme weather-
related (floods, storms,
related health effects
etc.) health effects
Human
Air pollution-related
exposures health effects
Regional weather Microbial changes:
Contamination Water and food-borne
Water and food-borne
changes pathways
Climate Contamination paths diseases
diseases
Change Transmission dynamics
Transmission
•Heat waves Vector-borne and
dynamics Vector borne and
•Extreme weather rodent- borne diseases
rodent borne diseases
•Temperature
•
•Precipitation
•Sea-level rise

12. Emerging Infectious Diseases
(EID)
• EID refers to newly identified, previously
unknown infections w/c cause public health
problems locally or internationally
e.g. SARS, H5N1 influenza, Nipah, Ebola,
Hepatitis C, hantavirus, etc.
• The emergence of these diseases may be
due to the combined impacts of rapid
demographic, environmental, social,
technological, lifestyle changes as well as
climate change.

13. Emerging Infectious Diseases (EID)
• Previously known diseases but are becoming to
be a public health problem for the past two
decades
•These may vary from one country to another and
in different regions of the country
Viruses Bacteria
Japanese encephalitis Leptospirosis
Chikungunya Legionella pneumophila
Dengue
Hepatitis C Parasites
HIV Paragonimiasis
Monkeypox Neurocysticercosis

14. Contributors to emerging
infections
1. Changing demographics
2. Pressure on the environment
3. International travel and commerce
4. Food supply and food technology
5. Microbial adaptation and change
6. Health systems breakdown

15. We live closely with insects
and animals.
• Anthroponoses vs. Zoonoses
• “Anthroponoses” (such as TB, HIV/AIDS, and
measles and indirectly-transmitted, vector-
borne anthroponoses (e.g. malaria, dengue
fever, yellow fever) ) vs. “Zoonoses” (e.g.,
rabies in dogs; bubonic plague, bird flu)

16. Emerging Infection Date identified
Human Immunodeficiency Virus 1
1983
(HIV 1)
Human Immunodeficiency Virus 2
1985
Emerging
(HIV 2)
Enterocytozoon Bieneusi 1985 infections in the
Human Herpesvirus 6 (HHV 6) 1986 past 20 years
Hepatitis C virus 1989
Hepatitis E virus 1990
Guanarito Virus 1991
Barmah Forest Virus 1992
Bartonella henselae 1992
Sin Nombre Hantavirus 1993
Cyclospora cayatenensis 1994
Sabia Virus 1994 Which emerging
Hendra Virus 1994
infections do you
Human Herpesvirus 8 1994
Lyssavirus (in Australia) 1996
think are public
Nipah Virus 1996 health threats to
New Variant Creuzfeldt-Jacob Disease 1996 the Philippines?
Highly Pathogenic Avian influenza 1997
West Nile Virus (in the United States) 1999
SARS CoV 2003
Monkeypox (in the United States) 2003

17. Re-emerging Infectious
Diseases
•Known diseases which reappear after
being eradicated (e.g. malaria, polio)
• Infections which are increasing in
incidence after they have been previously
controlled (e.g. Meningococcemia, Plague,
Cholera old serotype, Yellow Fever,
Diphtheria)

18. VECTOR-BORNE
DISEASE

19. Malaria and Dengue
• Mosquito vectors that spread malaria and
dengue need access to stagnant water in
order to breed, and the adults need humid
conditions for viability.
• Warmer temperatures enhance vector
breeding and reduce the pathogen’s
maturation period within the vector organism.
• However, very hot and dry conditions can
reduce mosquito survival

21. Malaria
• Changes in vector-borne diseases are
predicted (areas bordering current
endemic zones).
• Smaller changes in current endemic
areas (seasonal Malaria).
• Most temperate regions would remain
unsuitable for transmission

22. Estimated population at risk of dengue fever
under “standard” climate change scenario:
1990, 2085
1990
2085
.
Source. Hales S et al. Lancet (online) 6 August 2002. http://image.thelancet

23. Food and Water-borne
Diseases
• Higher temperatures & heavier rainfall events may
increase occurrence of water-borne diseases
• Sanitation services may be severely compromised
contributing to potential contamination of local water
supplies
• There may also be increases in infectious illnesses in
people using recreational waters (e.g. pools & beaches)
• Food-related concerns:
– outbreaks of toxic algae in saltwater that contaminate shellfish
(e.g. “red tide”)
– increased incidence of food poisoning related to warmer
temperatures that increase the survival of microbes and the
spread of toxins

24. Health effects
Health Effects
Temperature-related
illness and death
Extreme weather-
Extreme weather-
related (floods, storms,
related health effects
etc.) health effects
Human
Air pollution-related
exposures health effects
Regional weather Microbial changes:
Contamination Water and food-borne
Water and food-borne
changes pathways
Climate Contamination paths diseases
diseases
Change Transmission dynamics
Transmission
•Heat waves Vector-borne and
dynamics Vector borne and
•Extreme weather rodent- borne diseases
rodent borne diseases
•Temperature
•
•Precipitation
Changes in agro- Effects of food and
ecosystems, hydrology water shortages
•Sea-level rise
Socioeconomic and Mental, nutritional,
demographic disruption infectious-disease and
other effects

27. How do we monitor?
Source: WHO

28. How can we respond?

29. Source: WHO

30. What should be done now
• Community-wide understanding and
response, guided by policies informed by
good scientific advice
• Policy-focused assessment of the potential
health impacts of climate change
• Advocacy for:
– multidisciplinary assessments
– obtaining responses to questions asked by
stakeholders
– evaluation of risk management adaptation options
– addressing research gaps to facilitate decision-
making

31. Maraming salamat po