In my first post, I showed a map indicating that Aedes aegypti, the vector for dengue, could potentially move as far north as the UK by the end of the century. However, mosquitos have already invaded parts of Europe. As can be seen from the maps below, models show that areas of northern and eastern Europe have become more hospitable for A. albopictus mosquitos in recent decades.
Adapted from Caminade et al (2011). (a) the climate suitability for A. albopictus from 1960-1989. (b) the climate suitability for 1990-2009.
Until recently, cases of dengue were 'imported' into Europe from individuals travelling in areas where the disease is indigenous. However, in 2010, the first cases of locally-transmitted dengue in Europe were reported in France and Croatia. These were followed by a large outbreak in Madeira, Portugal that affected over 2000 individuals. Dengue has not been seen in Europe since the 1920s outbreak in Greece and Turkey that affected over a million individuals. Now that A. albopictus is permanently established on the Croatian coastline, there are concerns over history repeating itself. The World Health Organisation Regional Office for Europe blames the combined impacts of trade, travel and climate change for the increased risk of dengue in Europe.
There have been cases other locally-transmitted mosquito-borne diseases, such as chikungunya in Italy and France and malaria in Greece. Rates of West Nile virus infection have soared in the Mediterranean, and the first case of transmission in Germany was reported earlier this year. Mosquitos are not the only species gaining new footholds in Europe, either; diseases spread by insects and ticks are found to be most sensitive to a changing climate. Climate change has been linked to the change in the range of ticks (responsible for diseases such as tick-borne encephalitis [TBE]), with milder, shorter winters connected to an increase in TBE in Sweden. Sandflies, which transmit visceral leishmaniasis, are now found in Germany, with eleven cases of leishmaniasis reported so far.
For this blog, I have focussed on vector-borne diseases. However, climate change may cause disease outbreaks through other means. For example, there has been extensive flooding across Europe, including the UK, in recent weeks. Flooding can cause a host of physical and mental health problems, including localised disease outbreaks as sewers overflow and access to safe water is limited. While we have yet to experience an outbreak of this nature in the UK, climate change makes extreme weather events more likely; so there is a real threat of such an event occurring in the future unless our water systems are carefully managed. I highly recommend this blog, written by one of my coursemates here at UCL, to read more about flooding.
Due to its established healthcare systems and developed disease monitoring networks, Europe will be in a better position than most regions to tackle these challenges. The countries which are least responsible for emissions are likely to face the worst effects. The Green Climate Fund was established in 2010 to help developing countries to create climate-resilient infrastructure. However, the fund struggles to meet its target of annually raising $100 billion from developed nations by 2020. How this funding gap is addressed will shape the lives of millions of the world's poorest for decades to come.
Adapted from Carbon map – which countries are responsible for climate change? by the Guardian. The top map emphasises the most emitting countries while the bottom emphasises the most vulnerable countries.