The dengue vector Aedes aegypti: what comes next
Cassie C. Jansena, Nigel W. Beebea,b,*
aCSIRO Entomology, Long Pocket Laboratories, Indooroopilly, QLD 4068, Australia
bSchool of Biological Sciences, University of Queensland, St Lucia, QLD 4072, Australia
Received 14 December 2009; accepted 22 December 2009
Available online 22 January 2010
Aedes aegypti is the urban vector of dengue viruses worldwide. While climate influences the geographical distribution of this mosquito
species, other factors also determine the suitability of the physical environment. Importantly, the close association of A. aegypti with humans and
the domestic environment allows this species to persist in regions that may otherwise be unsuitable based on climatic factors alone. We highlight
the need to incorporate the impact of the urban environment in attempts to model the potential distribution of A. aegypti and we briefly discuss
the potential for future technology to aid management and control of this widespread vector species.
? 2010 Elsevier Masson SAS. All rights reserved.
Keywords: Aedes aegypti; Dengue; Climate change; Distribution
Aedes (Stegomyia) aegypti (Linneaus) is the major urban
vector of dengue viruses worldwide. Over the last 25 years,
there has been a global increase in both the distribution of A.
aegypti and epidemic dengue virus activity . The emergence
and re-emergence of epidemic dengue activity has prompted
much debate regarding the potential role of climate and
climatic changes in the changing epidemiology of the disease.
Likewise, the role of climate (average weather pattern in
a locality or region over time) and weather (local daily events
in the atmosphere) in determining the potential future
geographical distribution of A. aegytpi is a highly topical
subject. However, the domestic nature of this species probably
exerts more influence on its distribution than either climate or
climatic variables. Although A. aegypti is considered a tropical
mosquito  and its distribution does appear to be influenced
by climate in some temperate regions of the world,
contemporary and historical records document persistence
outside these regions.
A. aegypti is closely associated with human habitation and
readily enters buildings to feed and to rest . Adult females
preferentially feed on humans: other vertebrate species
constitute only a small proportion of their bloodmeals [3,4].
Unlike many other mosquito species, A. aegypti is a day-biting
mosquito, and often feeds on multiple hosts during a single
gonotrophic cycle. Females preferentially lay eggs in man-
made or artificial containers including water tanks, flower
vases, pot plant bases, discarded tyres, buckets or other
containers typically found around or inside the home . Eggs
are laid on or near the water surface in containers and, once
embryonated, can withstand desiccation for up to one year .
Juliano and Lounibos  determined that the occupancy of
human-dominated habitats is significantly associated with the
invasive status of a mosquito species. This association is
certainly evident for A. aegypti which readily exploits the
domestic environment, and which is still establishing in new
regions, despite adult A. aegypti mosquitoes demonstrating
very limited dispersal capability [7,8]. Indeed, the peri-
domestic behaviour of A. aegypti and its desiccation-resistant
eggs afford this species an alternative mode of long-distance
* Corresponding author. School of Biological Sciences, University of
Queensland, St Lucia, QLD 4072, Australia. Tel.: þ61 7 3365 2466; fax: þ61
7 3365 1655.
E-mail address: firstname.lastname@example.org (N.W. Beebe).
1286-4579/$ - see front matter ? 2010 Elsevier Masson SAS. All rights reserved.
Microbes and Infection 12 (2010) 272e279
dispersal via human-mediated transportation within and
While the distribution of A. aegypti is dependent on
climate to some extent, critical scrutiny must be applied to the
oversimplified assumption that climate change will indepen-
dently lead to an increased range for this species and
a concomitant expansion of the risk of dengue infections
around the world. Rather, as demonstrated below, a range of
dynamic factors must be considered when predicting future
global distribution trends. We show that several modelling
attempts fail to adequately address the implications of
a domestic lifestyle on the distribution of this species.
However, constraining the focus of models to a local and/or
regional scale rather than aspiring for global models may
increase their predictive capacity. In light of climate change,
the major drivers of future dengue will likely include e
unprecedented population growth, particularly in urban areas
of the tropics; an increase in the movement of both vectors
and viruses reservoir via modern transport; and a lack of
effective mosquito management . Despite the ability of
A. aegypti to persist in a range of urban localities and facil-
itate dengue epidemics in many countries, population
suppression or even eradication of this species is possible e
albeit that it requires both coordinated efforts and a sustained
commitment to vector management [9,10].
2. Global distribution of A. aegypti
Historically, A. aegypti has been able to establish in regions
between the northern January and southern July 10?C
isotherms  (Fig. 1). Originating in Africa, A. aegypti
probably invaded other continents via trading and transport
ships that resupplied in African ports during the fifteenth
through seventeenth centuries [2,11]. These ships carried
freshwater reservoirs on board and could maintain breeding
colonies of A. aegypti , and it is probable that A. aegypti
was introduced into the rest of the world on a number of
occasions via this means .
Given the occurrence of concurrent outbreaks of dengue
in Asia, Africa and North America in the late 1700s, it is
probable that dengue vectors (predominantly A. aegypti,
although there are others) have had a wide a distribution
throughout the world’s tropics for the last two centuries
. However, the introduction of A. aegypti into Asia
appears relatively recent, as endemic dengue fever in urban
areas was not recorded in this region until the late nine-
teenth century , and low genetic diversity across trop-
ical Asian populations suggests recent dispersal .
activity following 1945  and A. aegypti is currently
widespread in Asia .
Fig. 1. Current global dengue transmission risk map (yellow) also showing the hypothetical 10?C global winter isotherm distribution limits of A. aegypti proposed
originally by Christophers in 1960 . Map courtesy of WHO .
C.C. Jansen, N.W. Beebe / Microbes and Infection 12 (2010) 272e279
In the Americas, large and coordinated yellow fever erad-
ication efforts initiated by the Pan American Health Organi-
sation (PAHO) in the 1950s and 1960s saw a marked decline
in A. aegypti populations in that part of the world and the
subsequent successful eradication of the species in much of
Central and South America by the 1970s . However,
a reduction in control efforts in the early 1970s saw the
reinfestation of A. aegypti in most regions of both north and
south America, followed by subsequent epidemics of dengue
and the emergence of dengue hemorrhagic fever in some areas
Although A. aegypti was common in the Mediterranean
region prior to World War II , it also disappeared from
southern Europe and North Africa following this period. The
reason for this is unclear, although it is probably attributable to
malaria eradication efforts and widespread use of DDT .
While A. aegypti currently has a wide distribution in most
tropical and subtropical areas, the present distribution does not
reflect the maximum range of its potential distribution as
defined by historical records. This is particularly evident in
parts of Europe, in North America and in Australia where the
species has previously displayed a much larger geographical
distribution . Overall, the geographical distribution of
A. aegypti is not static, and appears to have undergone
significant changes in a number of continents over time.
3. Climate distribution and abundance
Climatic factors alone do not determine the geographical
distribution of A. aegypti, principally because the close asso-
ciation of A. aegypti with domestic environments affords this
species microenvironments which are highly moderated by
human behaviour and this in turn gives the mosquito the
ability to avoid the effects of transient weather to some
measure. For example, its use of manually filled water
receptacles obviates the mosquitoes’ reliance on rainfall to
flood suitable oviposition sites, and the tendency for adults to
rest indoors provides shelter and protection from external
While ostensibly a tropical mosquito, A. aegypti is
remarkable in its ability to accommodate adverse environ-
mental conditions. At one temperature extreme, laboratory
experiments show that A. aegypti larvae perish when the water
temperature exceeds 34?C while adults start to die as the air
temperature exceeds 40?C . Yet observations from the field
reveal A. aegypti existing and transmitting dengue in India’s
Thar desert townships in north-western Rajasthan, where the
mosquito avoids very hot ambient temperatures e often rising
above 40?C in summer e by exploiting household pitchers
and underground cement water tanks . Conversely, while
larvae can be susceptible to extreme conditions such as
freezing in laboratory experiments , observations from the
field have recorded viable A. aegypti larvae in ice-encrusted
water [2,22]. Additionally, populations of A. aegypti have
historically persisted in Memphis (USA) where minimum
winter temperatures commonly fall below 0?C , and in
Australia, historical collections have revealed the mosquitoes’
existence in towns with winter mean temperatures of 5e6?C
 e well below the hypothetical 10?C winter isotherm
limit displayed in Fig. 1 [2,24].
So while temperature does influence larval development
time and survival rate [2,25,26], temperature alone is generally
not a useful predictor for larval abundance . In Australia,
the current geographical range of A. aegytpi is not predicated
by climate, and an increase in mean temperatures on the east
coast of the continent over the past 60 years has not been
accompanied by an apparent southward increase of this vec-
tor’s distribution . Indeed, the distribution of A. aegypti in
Australia has retreated to Queensland since the mid-1900s,
despite historical distributions that reached at least as far south
as Culcairn in New South Wales (36?S; ).
In some regions, rainfall is positively correlated with larval
abundance, especially where rain-filled containers appear to be
the primary larval sites . While A. aegypti larvae require
water for survival, they readily utilise human-filled containers
and thus are not totally dependent on rainfall to flood their
container habitats. For example, in one north-eastern city of
Brazil, Pontes et al.  found A. aegypti abundance (indi-
cated using the House Index) to be independent of rainfall.
Rather, high vector abundance was correlated with increased
household storage of water during a period of local drought
and a simultaneous reduction of vector control activities. In
summary, the association between rainfall and A. aegypti
abundance will almost certainly vary between localities due to
both the range of container types that are available as larval
habitats and differences in the water storage practices of the
And while temperature, humidity and rainfall have overt
impacts on mosquito survival and ecology, other climatic
factors such as photoperiod and wind velocity may also be
influential. Importantly, it is necessary to consider that these
meteorological conditions have a combined effect on the
survival and development of mosquitoes and that it is difficult
to examine the potential impact of these factors independently
as a consequence. Also, general climatic observations may not
reflect the local microclimate experienced by individual
mosquitoes throughout their life stages.
4. Other factors driving geographical distribution
In most cases, it appears that the highly domestic nature of
A. aegypti means that humans, rather than climate, drive the
distribution of this species. While local weather may explain
the abundance of A. aegypti in a particular location at a given
time, other factors may be more predictive for the presence of
this species. Particular features that have been observed as
associated with A. aegypti’s presence include urbanisation,
socioeconomic factors, building design and construction
features, the quality of water supply and management, and the
quality of other public health infrastructure services [16,31]
Increases in the size and population density of major cities
place increasing demands on infrastructure and essential
services, particularly in developing countries. The response to
these demands may dramatically alter the suitability of
C.C. Jansen, N.W. Beebe / Microbes and Infection 12 (2010) 272e279
a locality for urban mosquito breeding. An absence or irreg-
ularity of water supply will lead to an increase in domestic
water storage practices which, in turn, will alter the landscape
of potential A. aegypti habitat e perhaps providing a far more
regular or numerous supply of larval sites. For example, the
potential increased risk of dengue re-emerging in Australia is
attributable to human adaptation to the current and projected
climate change scenarios which suggest the drying of southern
Australia, rather than directly to changes in the climate .
Indeed, it is the widespread installation of government sub-
sidised rainwater tanks intended to drought-proof urban areas
that may facilitate the re-appearance of A. aegypti in these
The degree of public health infrastructure in a community
can also influence the abundance of A. aegypti. For example,
poor sanitation standards which result in the accumulation of
debris and other material that collect rainwater can facilitate
major expansion ofthis mosquito’s
Conversely, A. aegypti can be very sensitive to well-imple-
mented control initiatives. As demonstrated by the widespread
PAHO mosquito control effort in the Americas, effective
A. aegypti population suppression and/or eradication is
possible, although maintenance of this control requires a long-
term commitment to urban vector management to prevent
recolonisation. Thus, governments with a robust public health
strategy may be better equipped to manage A. aegypti pop-
ulations and provide sustained vector control.
Biological interactions between species occupying similar
niches may also influence the distribution and abundance of A.
aegypti. For example, marked declines in both the abundance
and range of A. aegypti have been observed in association with
the invasion and geographic range expansion of the Asian tiger
mosquito, A. albopictus, particularly in some south-eastern
regions of the United States [32e34]. Whilst a number of
underlying processes including interspecific larval resource
competition have been suggested to explain this observed
trend [6,35], it is most likely that multiple factors determine
the current distributions of each species. Examples of these
interconnected factors include the potentially asymmetrical
effects of abiotic factors (including climate) on different life
cycle stages, apparent competition induced by parasites,
mating interference and variation between the microclimates
in given locations [6,35].
5. Climate, A. aegypti and dengue
As outbreaks of urban dengue are governed largely by the
simultaneous availability of the virus and containers for A.
aegypti oviposition and larval development, climatic vari-
ables may play a less critical role in dengue transmission
than is the case with other arboviruses . The distribution
of urban dengue is limited by the distribution of A. aegypti,
but the presence of the vector alone does not assure dengue
transmission, even if it is imported to a non-endemic region
. Rather, the pattern of dengue transmission depends on
the interaction ofnumerous
including virus multiplication dynamics, the ecology and
behaviour of its vectors, and the ecology, behaviour and
immunity of its human hosts. Importantly, however, climate
and weather may influence a number of these parameters (for
more detail see ).
First, the period of time before a mosquito is able to
transmit virus following an infectious bloodmeal (extrinsic
incubation period; EIP) is often temperature-dependant.
Indeed, the EIP of dengue virus in A. aegypti decreases with
increasing temperature [37,38]. Conversely, lower ambient
temperatures may lengthen the EIP, which may in turn
decrease dengue transmission as fewer mosquitoes live long
enough to transmit the virus.
In addition to influencing the duration of the EIP in the
mosquito, climatic factors may also influence its capacity to
transmit virus due to resultant changes in mosquito abundance
and survival. Low humidity can negatively affect adult
survival  and may decrease the proportion of the vector
population that survive the EIP and thus becomes infectious by
Finally, of course, humans also respond to meteorological
conditions. Thus, climate and weather may induce behavioural
changes in humans which in turn influence the transmission
dynamics of arboviral disease. As the larval habitat of A.
aegypti is largely comprised of artificial containers, domestic
water storage practices can directly influence the availability
of larval rearing sites. For example, increased urban water
hoarding in response to drought or decreased rainfall can
increase the number of productive larval sites if provisions are
not made to eliminate this risk e and thus too little rain may
lead to elevated A. aegypti densities.
In this way, human behaviour in response to climatic
variables can determine the extent to which individuals are
exposed to the bite of mosquitoes e as can accompanying
economic factors. For example, the installation of air condi-
tioning systems in conjunction with closed and/or screened
windows reduces exposure to adult A. aegypti, which readily
feed and rest indoors e but the adoption of these protective
measures can be driven more by economic than climatic
factors. In a study which compared serological survey results
between the two adjoining cities of Nuevo Laredo, Tamaulipas
(Mexico) and Laredo, Texas (USA), Reiter et al.  found
that the incidence of dengue cases was higher in Nuevo Lar-
edo, despite a higher abundance of A. aegypti across the border
in Laredo. The authors attributed the lower incidence of
dengue in Laredo primarily to characteristics of the houses
including the presence of air conditioning and screens on
windows, in addition to a lifestyle spent mainly inside sealed
buildings. These housing and lifestyle characteristics are not
popular in Nuevo Laredo, where income is much lower. Thus,
the authors suggest that the higher prevalence of dengue in
Mexico is chiefly due to economic rather than climatic factors.
Overall, when considering the effect of climate on the
transmission dynamics of mosquito-borne pathogens, it is
necessary to acknowledge the enormous complexity of the
vectorepathogenehost system. Fundamental climatic vari-
ables such as temperature, rainfall and humidity cannot be
considered independently as these factors usually provide
C.C. Jansen, N.W. Beebe / Microbes and Infection 12 (2010) 272e279
a cumulative influence upon disease transmission. Further-
more, short-term patterns of local weather, which may be most
important for dengue transmission, can be overlooked if
analysis is limited to the consideration of climate trends in
terms of longer term means and averages.
6. What about climate change?
While evidence continues to grow that future climates will
be affected by human-induced change , there is still great
uncertainty surrounding exactly what will happen in relation
to regional climates and weather and how this will play on
each landscape as more energy accumulates in the system due
to global warming.
6.1. Global scale models
In attempting to better understand and even forecast the
potential distribution of A. aegypti and the associated risk of
dengue transmission today and under future climate change
scenarios, global models have produced mixed results [41e
43]. Below, we give three examples e which vary in their
complexity e of attempts to develop global models of
potential dengue activity. Importantly, these global models
often do not resolve or consider patterns of historical dengue
The first of these global models involves the relatively
complex vectorial capacity and mosquito life-table models of
Jetten and Focks  and was used to project potential
changes in dengue transmission under current and future
climate warming scenarios. The authors modified the typical
vectorial capacity equation to develop an equation that
describes a critical density threshold e an estimate of the
number of adult female vectors required to maintain the virus
in a human population. The critical parameter of temperature
was used to make projections for 2?C and 4?C increases in
the current climate. Temperature alone was used because it
influences adult survival, the lengths of time between obtain-
ing a bloodmeal to developing an egg batch, the EIP of the
virus in the vector, and the vector’s size e a factor that also
indirectly influences the biting rate. The model described the
current dengue activity with an associated increase in trans-
mission and a possible expansion of potential dengue activity
through latitude and altitude under warming temperatures.
However while this model was validated using current patterns
of dengue activity, it acknowledges that it was limited by not
taking account of historical dengue activity in some regions
that are now dengue-free.
A second global model  is based on CIMSiM,
a mosquito life-table model that incorporates elements of
stochasticity, such as daily meteorological data with its
inherent variations and the daily changeability of larval food
delivery e which in this case was not limiting. Again, results
agreed with current observed global distributions of A. aegypti
with an increased latitudinal distribution in the warmer
summer months. Acknowledged issues with this model
included the very coarse resolution of 1?(w100 km grid), its
lack of focus on local weather, and a failure to incorporate
human-mediated environmental modifications.
Finally, a third attempt  estimated potential dengue
activity using vapour pressure and dengue distribution records
between 1975 and 1996 as its basis. This measure of humidity
was found to be the most important individual predictor of
dengue activity and a correlation between humidity and
current global dengue activity was presented in this work,
while projected warming through climate change scenarios
again suggested a potential latitudinal expansion beyond
present dengue activity. Authors limited their dengue activity
input data to exclude past dengue activity in some regions
including south-east Australia, and this resulted in projections
that could not accurately incorporate past dengue activity.
Any model of dengue risk is implicitly modelling the
potential distribution of the vector A. aegypti. As discussed
earlier, the historical distribution of this vector can be mostly
captured within a global winter isotherm of 10?C (Fig. 1) that
was first described by Christophers in 1960  and is still used
today by the World Health Organisation to describe the
species’ potential geographic limits . It is interesting that
the projections described above do not account for historical
dengue activity in places like Australia where, in first half of
the 20th century, dengue epidemics in southern Queensland
swept south into New South Wales reaching a town at 35?
latitude [29,44] e well beyond the limits projected by these
models. Indeed, some of these epidemics only stopped their
southern movement as winter encroached .
Environment can modify local microclimates in ways that
cannot be extrapolated from meteorological stations which are
usually positioned above the ground and away from vegetation
to restrict ground effects that can affect climate data. Weather
stations collect temperature, humidity, rainfall, pressure,
sunshine, wind, cloud and visibility data. However, natural and
artificial or human-modified ground features, vegetation and
ultimately human action and its attendant behaviours can all
modify these variables. These local conditions not only
produce microclimates that may be exploited as suitable
niches for mosquitoes, but they also render extrapolations
made from meteorological station data precarious as these
could generate inappropriate conclusions. Thus, for the
reasons discussed above, attempts to generate global models of
dengue risk are at best unhelpful and risk itself is unlikely to
be accurately captured in models that utilise parameters based
on means and averages.
human-induced microgeographic factors including the local
storage and water use behaviour as well as local climate .
Local mosquito infection dynamics and microepidemiological
factors such as herd immunity are also important factors in
the virus and vector genotype heterogeneity that will always
smaller scale models that use local climate characteristics to
modify local short-term associations may be more valuable, as
C.C. Jansen, N.W. Beebe / Microbes and Infection 12 (2010) 272e279
this may prove more informative in terms of understanding
disease epidemiology .
6.2. Climate envelope and mechanistic modelling
Given the potential of more intimate life process models
focusing on A. aegypti we describe below two independent
approaches that try to elucidate the historical and current
distribution of A. aegypti in Australia.
Throughout the 20th century, A. aegypti has occurred in
pockets of urban settlement across much of Australia’s conti-
nent with adistributionbothinside andoutsidethe 10?Cwinter
isotherm . Human behavioural changes in water storage
practices (particularly a move from rainwater tanks to reticu-
lated water supplies) probably assisted in the regression of A.
aegypti north into the warmer and more tropical regions of
Queensland . However when Australia’s historical conti-
nental distribution of A. aegypti was assessed using a climate
envelope modelling methodology (i.e. statistical/correlative
climate matching) in an attempt to project the mosquitoes’
not be realised, and the models wrongly suggested that this
species could exist in colder climates than had been observed.
This inappropriate result highlighted the fact that the biology
and ecology and thus the distribution of this mosquito itself are
more strongly influenced by human activity than by climate,
which essentially buffers the mosquito from the external envi-
ronment . For example, large domestic rainwater tanks
common throughout Australia in the early 20th century prob-
ably presented stable larval microclimates permitting pop-
the re-adoption of rainwater tanks in southern Australia as an
adaptation to climate change may see the re-emergence of this
vector further south once again.
A more successful approach in terms of indirectly
accounting for human behaviour traits was to construct
a mechanistic model around the organism or its key micro-
habitat e in this case, the water containers where eggs are
placed and larvae develop . This mechanistic or process
modelling approach is based around the mass energy transfer
kinetics of the larval container e a vital part of the life cycle e
and was superior in terms of resolving the historical and
current distribution of A. aegypti in Australia. It also provided
a much better understanding of A. aegypti’s historical persis-
tence in container habitats as well as its potential to adapt
Perhaps next generation modelling of A. aegypti distribu-
tion (and, in turn, of dengue activity) will be able to better
incorporate other important influential factors such as socio-
economic conditions, housing design, and water storage
practices and management.
7. Population suppression and eradication: looking
The domestic nature of A. aegypti can make it very sensitive
to control initiatives. As previously mentioned, effective A.
aegypti vector control is certainly possible, although mainte-
nance of population suppression requires a long-term commit-
undertaking that demands large resources and requires consid-
erable public education and the subsequent modification of
human behaviour e each of these components are essential for
the sustainability of any vector control method . Conse-
quently, governments with a robust and economically sustain-
A. aegypti populations and provide sustained vector control
initiatives, given their capacity for integrated vector manage-
ment and public engagement over time.
Contemporary eradication and control methods are not so
dissimilar to those employed over half a century ago e prin-
cipally top-down integrated vector management programs that
implement larval source reduction and are complemented by
modern insecticides and chemical larvicides. In Singapore,
elevated dengue activity in the 1960s saw the genesis of a top-
down vector control program that also utilised law enforce-
ment with a subsequent and dramatic reduction in both vector
abundance and dengue activity. Although dengue activity
increased a decade later, this was not due to an increase in
vector density but rather to a lowering in herd immunity of the
population (see  for more detail).
Biological interventions have shown some success in
copepods which eat mosquito larvae in Vietnam  e the
sustainability of which requires vigorous community engage-
ment to maintain copepod populations in water containers. A
questionremainswhether suchapproaches couldbe effectivein
While the tools described above have proven effective in
attempts to control A. aegypti in the highly urban regions
where it is now endemic, new A. aegypti population suppres-
sion and replacement tools may open a next chapter in our
battle against this vector. The Sterile Insect Technique (SIT) is
not a new approach for insect population control and has
already been successfully implemented against a range of
agricultural pest insects (reviewed in ). But the recently
system (Release of Insects Carrying
a Dominant Lethal) incorporates a novel genetic sexing system
for the mass rearing of male mosquitoes using a repressible
female specific lethal gene that permits the production of
male-only A. aegypti populations . This genetically
modified A. aegypti sterile male release technology creates
a species-specific population control method that relies
primarily on the mass rearing and release of sterile males only
, and provides a technology that appears to present an
exciting alternative to traditional A. aegypti population
suppression methods in that it makes use of species-specific
mate seeking behaviour to locate conspecific females and thus
generate no effect on non-target insects.
The second and equally exciting development in terms of
novel control strategies is the discovery that strains of the
naturally occurring endosymbiotic bacterium Wolbachia e
commonly present in insect populations e can inhibit
C.C. Jansen, N.W. Beebe / Microbes and Infection 12 (2010) 272e279
replication of the dengue virus in A. aegypti . Introducing
these strains of Wolbachia into wild populations of A. aegypti
could potentially underpin a population replacement strategy
that could suppress or perhaps even eliminate dengue trans-
mission in affected areas.
While neither of these novel tools is likely to be used alone,
they would perhaps rather be adopted as part of an integrated
vector management program. In light of the continuing global
expansion of dengue epidemic activity, consideration of novel
technologies such as these should be encouraged and
embraced when designing future vector control initiatives.
8. Concluding remarks
Meteorological variables alone cannot account for the
geographical distribution of A. aegypti. Patterns observed in
the historical distribution of this species also reflect global
trends in urbanisation, infrastructure development, socioeco-
nomic conditions and control efforts. The majority of attempts
to model the potential distribution of this species in relation to
climate have to date failed to adequately incorporate these
factors and now face the challenging task of incorporating and
addressing the important role that humans and the domestic
environment play in the local presence and abundance of A.
A. aegypti stands as a classic example of an invasive
species e and its close association with the human environ-
ment affords it the ability to persist in locations that may
otherwise be unsuitable in terms of climatic conditions alone.
Given this, and even in light of all the evidence of current and
continuing anthropogenic climate change, the major drivers of
past and most likely future dengue growth appear to remain
the same. These include i) unprecedented population growth,
particularly in urban areas of the tropics; ii) an increase in the
movement of both vectors and viruses in human hosts via
modern transport; and iii) a lack of effective mosquito
management in terms of government policy and public health
. Changes in climate will impact on various aspects of
these factors, but human behaviour and the conditions of the
domestic environment remain far more influential in terms of
the distribution of A. aegypti and the epidemiology of dengue
under any projected climate scenario.
The author CCJ is funded through a Postdoctoral Fellow-
ship from the CSIRO Office of the Chief Executive (OCE).
NWB is supported through a jointly funded position by the
University of Queensland and the CSIRO Entomology. The
authors would also like to thank Craig Williams for sugges-
tions regarding the manuscript.
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