1. Climate and Public Health Systems: Vector-borne diseases
George K. Christophides, Imperial College London & The Cyprus Institute

2. Climate and Environmental Change Impacts on Public Health
Heat extremes: cardiovascular and cerebrovascular diseases, mental health
Air quality: respiratory diseases and allergies
Food and water: diarrheal diseases
Precipitation extremes: water-borne diseases, lower respiratory tract infections, fungal infections
Dust storms: bacterial meningitis and other infections, respiratory conditions
Vector-borne diseases: DEN, CHIK, Zika, YF, RVF, CCHF, Malaria
Climate and environmental change impacts on public health can be distinguished into direct and indirect. Indirect are those stemming from issues resulting in pressures on public health services like migration and financial instability. I will not discuss these further but rather focus on the direct impacts.
-Heat extremes can have tremendous impacts on cardiovascular and cerebrovascular diseases, like heart attacks and heat strokes, especially in the aging populations of the South European countries, and can also aggravate existing mental conditions.
-Worsened air quality from increased gas concentrations will impact on respiratory conditions including lung function and allergies.
-Decreased food and water quality due to high temperatures and scarcity of clean water can increase dramatically diarrheal diseases. I don’t think we will have problems of clean water availability in Southern Europe but we may do so in North Africa and the Middle East.
-Extreme precipitation events will increase the risk of water-borne diseases and infections of the lower respiratory tract and fungal infections, but this may not be much of a problem here.
-Dust storms can trigger bacterial infections such as meningitis and viral infections in addition to aggravating respiratory conditions.
-Finally, diseases that are transmitted by vectors are expected to be massively affected, and this is the focus of the rest of my talk.

3. The world's deadliest animal
Had I asked you to tell me which is the world’s deadliest animal, I am sure many of you would think of snakes, crocodiles, lions or sharks. The truth is that the most dangerous animal on earth is the mosquito, even deadlier than us humans. It kills well over half a million people every year, and the burden it brings to global economy and development is huge with infections reaching up to half a billion every year.

4. 2012 Paphos workshop on Climate and VBDs
The impacts of climate on the spread of such diseases are largely due to the spread and size of vector populations, but are also affected by human activities such as migration and travelling.
In 2012, we organized a workshop to analyze the climate change impacts on vector borne diseases in the Eastern Mediterranean and the Middle East. From this workshop, a list of existing threats, potential threats and low threats was produced.
I will focus on potential threats that are the ones we really must pay attention to. Amongst them are the Chikungunya, Dengue, Rift Valley and Yellow fever that are caused by viruses transmitted by mosquitoes. In this list I will now also include Zika, which we didn't know about back then.
ZIKV

5. Systems modeling: from local to global
Chikungunya epidemic in the Indian Ocean and 2016 Zika epidemic in the Americas were facilitated by single genetic mutations that made viruses better transmitted by mosquitoes that became very abundant due to the changing environment and climate
These diseases are very complex to study and even more so to model as one has to consider the interaction between 3 organisms and the environment. Critically, in such complex systems, a tiny little change in one variable can have a huge impact on the entire system.
Prime examples are the Chikungunya epidemic in the Indian Ocean in and the Zika epidemic in the Americas in seem to have been both facilitated by single genetic mutations in each of these viruses that made them better transmitted by mosquitoes.
A small (and sometimes) local change can have a huge impact on the homeostasis of the entire and sometimes global system

6. Asian tiger mosquito: Dengue, Chik, Yellow Fever and Zika
The Asian tiger mosquito that can transmit most of these diseases was introduced in Europe about 20 years ago through global trait of goods and established itself across southern Europe because of the warming climate.
Our predictions from integrated ecological, population and climate models is that this mosquito can imminently spread to and establish in northern Europe including North France, Germany, the lower countries, the UK and Ireland.
Confirmed presence by January 2017
Current habitat suitability

7. Shift in tiger mosquito habitat suitability by 2050
And this are our global predictions for 2050, in a nice graphic view produced by National Geographic. Focusing on Europe and the US; whilst the currently highly suitable regions of South Europe and Florida may become slightly less suitable, suitability moves pole-ward so much so that these mosquitoes will infest the whole of Europe and the US, apart from the Alps and the Rocky Mountains.
Ryan Taylor Williams, National Geographics

8. Human activities: socioeconomic and political factors
>1M cases (90% of Athens’ population), >1500 deaths
Regional conflicts and societal upheavals, migration flow, temporal settlements, poor housing and hygiene standards, financial depression
As I said before the spread of Vector-borne Diseases is largely impacted by human activities, which in turn can be caused by socioeconomic and political factors.
We don’t need to go far. A few years after the Greko-Turkish war in , Greece was hit by the largest ever Dengue outbreak in Europe. Over 1 million people were infected mostly in Athens and Piraeus, which took the main hit, and 1500 people died. The outbreak was triggered by the huge human migration from Asia Minor because of the war and subsequent population exchange. These people lived in temporal settlements with custom made water containers where millions of mosquitoes were breeding, in very poor housing and hygiene standards in a country that was in deep financial depression.
Of course you would think these were very different times. But are they really? This picture is taken at a refugee camp in Greece last year. If you ask me whether there is a risk of vector-borne diseases appearing there, I would say most certainly yes and we are lucky this didn’t happen yet.
Yet there is a difference. The Dengue outbreak in Greece didn’t become a European pandemic because of limited travelling at that time, which is not the case today.