Climate, Land use, and Public health

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Climate, Land use, and Public health
National Symposium on Climate Change and Human
Health Canberra, September 29, 2003
Jonathan Patz, MD, MPHJohns Hopkins
University Bloomberg School of Public Health
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Or an alternate titleClimate Change is Global,
but the Impacts are Localso local terrain
and/or human activity can determine population
vulnerability
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Climate/Land use interface

• Climate change attributes
• Increased temperatures extremes of the water
  cycle sea level rise
• Land use effect modification (of climate
  exposure)
• Surface heat capacity (e.g., asphalt roads,
  concrete buildings
• Local topography determines local climate
• Water stress (e.g. from irrigation)
• Water contamination risks (e.g. from livestock
  agriculture)
• Concomitant ecosystems pressures (e.g.,
  deforestation, desertification)

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The Heat Island
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Relationship between temperature and ground-level
ozone
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Relationship between malaria and altitude,
Zimbabwe. Altitude a good surrogate for
temperature the average temperature decrease
with height 6C per 1000 meters
Johns Hopkins University School of Public
Health Course Global Environment and Health
Source Taylor and Mutambu, 1986
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Baseline 2000 2025 2050 2075 2100
Courtesy Kris Ebi
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Baseline 2000 2025 2050 2075 2100
Courtesy Kris Ebi
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Baseline 2000 2025 2050 2075 2100
Courtesy Kris Ebi
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Johns Hopkins University School of Public
Health Course Global Environment and Health
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Lake Chad shrank by 95 since 1963

• River flow from Chari and Logone rivers down by
  75, diverted for irrigation
• 1963 lake size 9700 sq. mi.
• 2000 lake size 580 sq. mi.
• Failed monsoons has exacerbated problem
• Increased demand for irrigation under harsh
  climate condition may worsen problem

Johns Hopkins University School of Public
Health Course Global Environment and Health
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Pathogens on the move?
(NASA)
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Climate change Its not just about warming.

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Johns Hopkins University School of Public
Health Course Global Environment and Health
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Johns Hopkins University School of Public
Health Course Global Environment and Health
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Integrated assessment of cryptosporidiosis risk
under future climate change scenarios. Study
site (Lancaster county), 64 of livestock
operations tested positive for crypto oocysts in
manure. (Graczyk et al 2000) For all waterborne
disease outbreaks in US, 1948-94, significant
assoc. with preceding heavy rainfall events
(Curriero, Patz et al 2001)
Johns Hopkins University School of Public
Health Course Global Environment and Health
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El Niño-related forest fires, Indonesia
,1998 Due to lack of monsoon rains accompanying
El Niño.
Johns Hopkins University School of Public
Health Course Global Environment and Health
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Courtesy K.W. Chua
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Nipah Virus Outbreak

• 265 PATIENTS HAD VIRAL ENCEPHALITIS.
• 105 FATALITIES.
• Last fatal acute case 27th May 1999.
• 1 million pigs were culled.
• 800 pig-farms were demolished.

Courtesy K.W. Chua
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1997/1998 ENSO event (El Niño Southern
Oscillation)
Severe Drought In Southeast Asia
Courtesy K.W. Chua
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Courtesy K.W. Chua
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Courtesy K.W. Chua
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Courtesy K.W. Chua
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Johns Hopkins University School of Public
Health Course Global Environment and Health
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Trophic Cascade Hypothesis(TCH)

• Changes associated with El Niño alter weather
  patterns in U.S. Southwest
• Increased winter-spring precipitation leads to
  increases in vegetation and insect populations
• Increases in food and shelter increase
  size/density of rodent populations
• Increases in density alters the quantity/quality
  of SNV infection in Peromyscus populations
• Return of normal weather patterns leads to
  increased contact with humans

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West Nile Virus Transmission Cycle in Old World
Mosquito vectors Culex species
VIRUS
?
VIRUS
VIRUS
Dead - end Hosts
Avian reservoirs
USGS, National Wildlife Health Center
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West NileConditions in NYC Area in 1999

• Early season rain and summer drought provided
  ideal conditions for Culex mosquitoes
• July, 1999 Hottest July on record for NYC
• Suburban/urban ecosystems support high numbers of
  select avian host and mosquito vector species
  adapted to those conditions
• High populations of susceptible bird species
  existed, especially locally mobile American crows
• Suburban/urban ecosystems conducive for close
  interaction of mosquitoes, birds, and humans

USGS, National Wildlife Health Center
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Dissemination of WNV by migratory birds?
USGS, National Wildlife Health Center
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2002 West Niles Year of Reckoning
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WNV and DROUGHT CASE REPORTS Romania
1996 Neurological disease Hundreds, Fatalities
17 Prolonged drought and heatwave. Bucharest
cases concentrated in blockhouses over aging
sewage system where C. pipiens was breeding in
abundance.   Volgograd 1999 Hospitalized 626,
Meningoencephalitis 84, Fatalities 40 Followed a
drought.   Israel 2000 Serologically confirmed
417, Fatalities 35 Drought across southern Europe
and Middle East. C. pipiens identified as a
vector.   US 1999 Neurological disease 62,
Fatalities 7, Sequelae gt½   Severe spring/summer
drought, mild winter and 3-week July
heatwave.   US 2002 Human cases 3737,
Fatalities 214, 43 US states, DC and 5
Canadian Provinces   Severe drought East Coast.
Absence of snowpack in the Rockies.
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West Nile, USA, 2003
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West Nile VirusConditions in Colorado, July,
2003

• Pueblo, CO, July 13, 2003, a new all time record
  for maximum temperature 109F
• Grand Junction, CO, a new record set for the
  number of 100F days for a single month on July
  22, 2003. July 22nd was the seventeenth day of
  triple digit temperatures.
• Grand Junction, CO, hottest July on record, and
  the hottest month on record. Average temperature
  was 84.1F, or 7.3F above normal.
• Denver, CO, average July temperature was 76.9F,
  or 3.5F above normal. Fourth warmest July on
  record.

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Conclusions

• The impacts of climate change, a global process,
  will be realized at the local and regional
  levels. They will unfold in the context of
  concomitant land use and ecological changes.
• Further understanding of the confluence between
  these processes must be a priority for future
  research and assessments

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www.jhsph.edu/globalchange
Thank you