Environmental Engineering Reference
In-Depth Information
Chapter 10
Australia's Dengue Risk: Human Adaptation to
Climate Change
Nigel W. Beebe, Robert D. Cooper, Pipi Mottram,
and Anthony W. Sweeney
INTRODUCTION
The reduced rainfall in southeast Australia has placed this region's urban and rural
communities on escalating water restrictions, with anthropogenic climate change fore-
casts suggesting that this drying trend will continue. To mitigate the stress this may
place on domestic water supply, governments have encouraged the installation of large
domestic water tanks in towns and cities throughout this region. These prospective sta-
ble mosquito larval sites create the possibility of the reintroduction of Ae. aegypti from
Queensland, where it remains endemic, back into New South Wales (NSW) and other
populated centers in Australia, along with the associated emerging and re-emerging
dengue risk if the virus was to be introduced.
Having collated the known distribution of Ae. aegypti in Australia, we built distri-
butional models using a genetic algorithm to project Ae. Aegypti's distribution under
today's climate and under climate change scenarios for 2030 and 2050 and compared
the outputs to published theoretical temperature limits. Incongruence identifi ed be-
tween the models and theoretical temperature limits highlighted the diffi culty of using
point occurrence data to study a species whose distribution is mediated more by hu-
man activity than by climate. Synthesis of this data with dengue transmission climate
limits in Australia derived from historical dengue epidemics suggested that a prolifera-
tion of domestic water storage tanks in Australia could result in another range expan-
sion of Ae. aegypti which would present a risk of dengue transmission in most major
cities during their warm summer months.
In the debate of the role climate change will play in the future range of dengue in
Australia, we conclude that the increased risk of an Ae. aegypti range expansion in
Australia would be due not directly to climate change but rather to human adaptation
to the current and forecasted regional drying through the installation of large domestic
water storing containers. The expansion of this effi cient dengue vector presents both
an emerging and re-emerging disease risk to Australia. Therefore, if the installation
and maintenance of domestic water storage tanks is not tightly controlled, Ae. aegypti
could expand its range again and cohabit with the majority of Australia's population,
presenting a high potential dengue transmission risk during our warm summers.
Aedes (Stegomyia) aegypti (Linneaus) is an important vector of dengue and other
arboviruses. Despite its limited fl ight dispersal capability [1, 2], its close association
with humans and its desiccation-resistant eggs have facilitated many long distance
 
 
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