Viruses Emerging in Australia:The (Likely) Influence of Climate Change
Viruses in May, ’10KatoombaKatoomba
A.J. McMichaelNational Centre for Epidemiology and Population Health
The Australian National University Canberra, AustraliaCanberra, Australia
Newly Emerging Diseases (Morens et al, 2004)13 of 17 are viral
Re-Emerging Diseases (Morens et al, 2004)7 of 21 are viral
Breaches in the species barrier: Selected emerging infections in humans since 1976
Infection Animal linked Year infectionto transmission first reported
Ebola virus Bats 1976Ebola virus Bats 1976
HIV-1 Primates 1981
E. coli O157:H7 Cattle 1982
Borrelia burgdorferi Rodents 1982
HIV-2 Primate 1986
Hendra virus Bats 1994
BSE/vCJD Cattle 1996
Austn lyssavirus Bats 1996
H5N1 influenza A Chickens 1997H5N1 influenza A Chickens 1997
Nipah virus Bats 1999
SARS coronavirus Palm civets 2003
Influenza (H1N1) Swine 2009
Major factors enhancing infectious disease emergence and spread
Population growth, urban density: crowds, contactsPeri-urban poverty: privation, under-nutrition, poor hygieneUrbanization: sexual relations, mobility, mixing, etc.Globalization: distance/speed of travel/trade Intensified livestock production: BSE/vCJD Nipah virus bird ’fluIntensified livestock production: BSE/vCJD, Nipah virus, bird fluLive animal food-markets: longer supply lines – SARS, HIV?, etc.Disrupted ecosystems: dams, deforestation, biodiversity loss – e.g. various new Sth American rural haemorrhagic viral diseasesvarious new Sth American rural haemorrhagic viral diseasesGlobal climate changeBiomedical exchange of human tissues: transfusion, transplantsAntibiotic use/misuse: humans, livestock production, house-plantsIncreased human susceptibility: under-nutrition, population ageing, HIV IV drug use etcHIV, IV drug use, etc.
Temperature and tick-borne encephalitis (TBE) in Czech Republic
500
450
( ) p1993 to 2002: n=5,873 casesTBE
Cases450
400
350
300
250
200200
150
100y = 0.6536x2.1743
R2 = 0.9501
100
50
0
Source: Daniel, et. al. 2006
−5 0 5 10 15 20Temperature oC
Geographical distribution of Aedes albopictus* mosquitoof Aedes albopictus mosquito
Vector for:• Dengue
Before 1980
• Dengue• West Nile Virus• Chikungunya
Expansion 1981 to 2005• Japaneseencephalitis
Nipah Virus Disease: Outbreak in Malaysian Pig Farmers, 1997-1999y g ,Fruit bats (~40% carry the virus)
Forest clearing
Fruit orchardsVirus-contaminated fruit, bat droppings
Intensivepig farming Eaten by pigs
Infected (sick) pigs
El Niño drying (1998!)
Forest-fire smoke ?
Rain Forest, with seasonal f i i
265 humans infected:JE-like illness
fruiting: bat food
~40% fatal~105 deaths
2020s 2090s
Projected Global Warming: IPCC (2007)combined results of multiple model runs published by ~20 different modelling groups around world
2020s 2090s
A2
6.0
5.0
4.0
A1B
3.0
2.0
Av. surface warming, oC
A2
A1B
1.8 - 4.0oC
B1
Since 1950: + 0.7oC
1.0
0
-1 0
Reference 1980-99 temperature
B1
1900 2000 2100Year 0o 3.5o 7.0o
(Temp Rise oC)
1.0
Temperature projections, for 3 (of 6) different emissions projections:A2 relatively high A1B mid level emissions
(Temp Rise, oC)
A1B mid-levelB1 low
INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE, 2007
emissions
Atmosphere concentrations remain as in 2000
Earth’s Temperature Chart, since Dinosaur Extinction 65m yrs agoDinosaur Extinction 65m yrs ago
West Antarctic ice sheet begins
Arctic ice sheets appear
East Antarctic ice sheet begins
12
5oC warmer than now
Paleocene
3oC warmer than now
1.5oC warmerthan now
1284
Temp oC*(vs 1961-90)
?s
s
60 50 40 30 20 10 N
1961-90 av temp0-4 Last 2m yr
= ice-age
60myr 50myr 40myr 30myr 20myr 10myr Now
Millions of Years Before Present* Global temperature
d t d
Sea level 25-40 metres higher
measured at deep ocean
than nowTripati et al Science 2009
Satellite-based measures of average global temperature (near-surface lower atmosphere),
by year (Sept-Feb period) 1979-2010by year (Sept-Feb period), 1979-2010
2009 100.5
Long-term uptrend continues
1997-982003-04
2009-100.4
0.3
0.2
0.1
Temperature variation (oC),relative to reference 10 years of alleged
Reference temperature,(1979-1998 average)
0
- 0.1
- 0.2
reference temperature ‘cooling’ since 1998
(popular ‘sceptic’ argument … i.e., before more recent
- 0.3
- 0.4
data appeared)
1980 1985 1990 1995 2000 2005 2010
Monthly data from: http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts+dSST.txt
Aust. Bureau of Meteorology: Projected Temperature Rises to 2030
Summer Winter ANNUAL
Best estimate (50thSpringAutumn(
percentile) of change in average temperature (oC) over land by 2030( C) over land by 2030 for A1B emission (‘medium’) scenario
0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3
BoM: Best estimates of annual % change in precipitation (3 global emissions scenarios)
2030 2050 2070
(low)
(high)
-40% -20 -10 -5 -2 2 5 10 20 40%
Climate and Infectious DiseaseClimate and Infectious Disease
Climatic conditions set the geographic andClimatic conditions set the geographic and seasonal boundaries of potential transmission.
Other environmental, social and behavioural factors – and public health strategies –p gdetermine where/when actual transmissionoccurs.
Zoonoses: Climatic andSeasonal Variations inSeasonal Variations in
Vector and Host-SpeciesL me disease hite footed
Vector-borne zoonoses mostly maintained by wildlife
Lyme disease: white-footed mouse and its acorn feed
• Humans are incidental to their ecology
Vectors and animal host species undergo seasonal and inter annual variations in numbers and activitiesinter-annual variations in numbers and activities
• Vector activity reflects temperature and humidity• Host species population size and distribution affected by weather andHost species population size and distribution affected by weather and
(climate-related) resource availability
Pathogen may also be affected by climatic conditions
Climatic Influences on Viral Disease Occurrence
Temperature
Viral replication rate
Climate change
Temperature
Surface Natural
Mosquitoes, ticks, etc. Human
viral ID
Rainfall water
Humidity
Natural habitat
Animal reservoir
Human viral ID
Spill-overs
Winds, drying, dust
viral ID
e.g. meningitis in W Africa Human
Under-nutrition;social disruption & displacement
Vulnerability to ID
ID
p
Potential weeks of activity of Aedes albopictus mosquito in Europe (current): Spring hatching to Autumn diapause
Weeks01-89-1314-1516-1819-2021-2223-24
Schaffner F, et al. Development of Aedes albopictus risk maps. ECDC, Stockholm 2008. (Forthcoming.)
Climate Change and Viral Diseases of Interest in AustraliaDiseases of Interest in Australia
Vector-borneHuman only: Dengue fever, Chikungunya (?)
Zoonotic: Ross River, Barmah Forest, MVE, K njin Japanese encephalitisKunjin, Japanese encephalitis
Contagious, person-to-persong , p pInfluenza (emergence and spread of new strains)Respiratory syncytial virus?? Changes in contact probabilities and behaviours
- hep B, hep C, HPV, HIV
DENGUE FEVER: Estimated geographic region suitable* for A. aegypti vector, and hence transmission:
Climate conditions now and in alternative scenarios for 2050Climate conditions now and in alternative scenarios for 2050
Darwin
Katherine
..
2050 risk region: Medium GHG
Cairns
Mackay
Rockhampton
Townsville
Port Hedland
Broome.. .. .Darwin
Katherine
CairnsBroome
..
.. 2050 risk region: Medium GHG
emissions scenariop.
Carnarvon.Mackay
Rockhampton
Townsville
Port Hedland
Broome ... ..Current risk region, for d t i i Dar in
Brisbane
Brisbane.dengue transmission Darwin
Katherine
Cairns
TownsvilleBroome.
. ...
Mackay
Rockhampton
Port Hedland. ..Carnarvon. 2050 risk region: High GHG
emissions scenario Brisbane
* Gl b l i i l d l (H l )
NCEPH/CSIRO/BoM/UnivOtago, 2003
* Global statistical model (Hales), applied to Australia: Function of water vapour pressure (rainfall humidity).
Areas suitable for dengue transmission in 2100 under 4 climate change scenarios (grey = ≥50% likelihood of transmission)
Bambrick et al., 2009, Global Hlth Action
Map-projection of changes to rainfallchanges to rainfall across Australia to 2100 under ‘dry’ and ‘wet’ scenarios. B d bli h d
2. Hot, Median humidity1. Hot & Dry
Based on published literature, then modelled how these changes would affect gdisease distribution over space and time.
4. Warm (strong mitigation)3. Hot & Wet
No. of people in regions at high risk (≥50%) of dengue transmission, under four climate change scenarios
3 h /
Modelling done for Garnaut Review, 2008-
3. hot/wet,
09, by ANU/UWS team
1. Hot/dry
2. hot/medium
4. Warm (strong iti ti )
2. hot/mediumhumidity
mitigation)
Is climate change increasing the northern limit of Culicoidesvectors of Bluetongue virus in Europe?
Northern limit, C. imicola group: 2004
Northern range of virus: 2004
p
C
Northern range of virus: < 1998
Northern limit, C. imicola group: < 1998
C. pulcaris C. Obselitus C. imicolaCurrent northern limitNorthern limit
Source: Purse et al, 2005 Nature Reviews Microbiology
Northern limit < 1998Southern limit
Bluetongue Virus Zones in Australia, December 2009
Possible transmissionSurveillance
Surveillance data on distribution of bluetongue and culicoides vector from National Arbovirus Monitoring Program, administered by Animal Health Australia
SurveillanceFree
Eric Barron: Beyond Climate ScienceScience 2009; 326: 643Editorial
“Currently 40 years of intensive climate“Currently, 40 years of intensive climate model development is being coupled to what amounts to a cottage industry ofwhat amounts to a cottage industry of impact sciences. “Th lt i th t d t di f“The result is that our understanding of how ecosystems, water, human health,
i lt d ill d tagriculture, and energy will respond to climate change advances only slowly.”