As already hinted from my previous post, I will be looking at mosquitoes!
Most of us, have at least once in
our lives been bitten by one or more mosquitoes. We all know that mosquito
bites are itchy and are rather uncomfortable when trying to sleep. Although,
the effects of these bites are unpleasant, we never expect these bites to cause
us any serious harm or severe illness in Europe.
However, scientists have warned that the number of harmful diseased mosquitoes
spreading across the European continent is on the rise bringing new public health surprises!
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| Asian Tiger Mosquito (Aedes albopictus) |
In Europe, the Asian Tiger
mosquito (Aedes albopictus) is an
invasive species that has the potential to transmit infectious diseases such as
dengue and chikungunya fever. The mosquito is native to the tropical and
sub-tropical areas of Southeast Asia (Caminade et al.2012).
However, over the last couple of decades,
owing to increasing international travel and the global transport of goods, the
Asian Tiger mosquito has invaded many countries around the world and has been
ranked as one of the “World’s Worst” invaders by the Global
Invasive Species Database.
These mosquitoes have the ability to out compete
and completely eradicate other species with similar breeding habitats, as they
lay drought-resistant eggs (Benedict et al. 2007). This is what makes this invasive species so
dangerous!
As well as many other incidents,
the Asian tiger mosquito was responsible for the outbreak of Chikungunya fever
that occurred in the Italian province of Ravenna, summer 2007 (Enserink 2007). More than 200 people were infected with the
disease (ECDC
2007). Scientists have investigated these recent outbreaks and have related
them to the wetter and warmer climate patterns over central Europe (Gould et al. 2010).
The map below shows the known distribution of the Asian tiger mosquito in 2011.
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| Known distribution of A. albopictus based on field observations from the ECDC/VBORNET project (December 2011) |
So what impact will our warming
climate have on the spread of infectious disease carrying mosquitoes?
Through the use of regional
climate model scenarios for the future and high-resolution observations, scientists
from the University of Liverpool have investigated the suitability of Europe
for A. albopictus by using both
recent and future climate conditions (Caminade et al. 2012). The results showed that during the
1960-80s, northern coasts of Spain, Italy and southern France were climatically
suitable areas for the establishment of these mosquitoes. The
main finding of the study showed that over the last two decades climate
conditions have become more suitable for the mosquitoes over central
northwestern Europe and the Balkans, whilst they have become less suitable in southern
Spain and areas around the Mediterranean basin (Caminade et al. 2012).
Future trends show a similar
pattern with climate suitability for mosquitoes increasing over northern Europe
(including southern UK) as winters become warmer and wetter. In contrast, conditions
appear to become more unsuitable over southern European countries such as Spain
and Portugal, as more droughts are predicted in these areas in the future (see figure below).
Several other studies modelling and mapping the distribution and survival of Asian tiger mosquitoes across Europe, such as those carried out by Fischer et al. (2011) and Medlock et al. (2006), show similar distribution trends across Europe. Large areas of western and central Europe that are inappropriate for the
species today are projected to change during the 21st century towards a
climate that can support the survival of the species.
Thus, climate change is affecting the distribution of mosquito populations and thus the spread of infectious diseases across Europe. It is clear that in the future, unintended anthropogenic introduction can be expected as a constant source of insecurity. European health officials must be prepared and ready to tackle future epidemics of vectorborne and waterborne infectious diseases.
Climate change will have enormous implications for human health in the future.
Further Reading:
Is Climate Change Aiding the Spread of Disease?
Climate change will have enormous implications for human health in the future.
Further Reading:
Is Climate Change Aiding the Spread of Disease?
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