Case study: Mosquito-borne diseases
Tropical mosquitoes are travelling the world
Some tropical mosquitoes are travelling the world and establishing themselves on new continents. Previously they would only have been found in tree holes in forest areas of the tropics. But with urbanisation and the expansion of cities into the forest, mosquitoes are adapting to urban habitats such as water containers, rubbish heaps and used tyres – anywhere where water collects.
Used tyres are often transported around the world to be sold for recycling and retreading. Any mosquito eggs in the tyres go with them. The ability of laid eggs to survive out of water for over a year means that when they arrive from the tropics in North America or Europe they can re-establish themselves as soon as it rains.
Asian mosquitoes are now found across most of the USA and in more than 20 European countries. In the tropics they are important carriers (disease vectors) of the dengue and chikungunya viruses. These viruses frequently infect those travelling to the tropics. When infected travellers return home they bring the disease with them, to a place where the vectors are becoming more common. This leads to local outbreaks of tropical diseases in Europe and the USA.Lead image:
Bobinson K B/Flickr CC BY NC