Invasions of vector-borne diseases driven by transportation and climate change
In: Emerging pests and vector-borne diseases in EuropeSearch for other papers by Wouter J. van der Weijden in
Current site
Google Scholar
PubMed
Search for other papers by René A.L. Marcelis in
Current site
Google Scholar
PubMed
Search for other papers by Wilfred Reinhold in
Current site
Google Scholar
PubMed
Biological invasions are as old as life itself but have become increasingly frequent due to the globalisation of travel and transportation. During the latest decades, climate change has become an additional driver. Vector-borne diseases, too, are invading more frequently, following an invasion of a vector, a pathogen, a reservoir host or a combination of these. In the past, such invasions have had dramatic effects on public health (e.g. the plague in Europe), livestock health (e.g. bluetongue in southern Europe) or wildlife (e.g. avian malaria on Hawaii). As the volume and speed of travel and transportation increase and climate change continues, more invasions of vector-borne diseases are to be expected, also in Europe. Recent arrivals include the West-Nile, Usutu and bluetongue viruses and the mosquito vector Aedes albopictus (Skuse). Around 12 arboviruses are potential candidates for invasion in Europe in the next decades as well as at least one rickettsia, one bacterium and two protozoa. However, the likelihood of such invasions is small in most cases. The main vectors involved are ticks and Aedes and Culex mosquitoes. Two serious threats are invasions of the Chikungunya and dengue viruses in southern Europe, where the competent vector Ae. albopictus has already become established. In fact, at the time of writing this article (August 2007) an outbreak of Chikungunya occurred in Italy (see Chapter 10). An increasingly important risk route for disease introductions is that between East Asia and Europe. Whilst most climate-driven invasions cannot be prevented, many transportation-driven invasions can be. This requires a precautionary approach based on risk analyses, preventive measures in the country of origin, intensive surveillance, early warning and interception. High-risk trade flows for pathogens, such as live animals, and for mosquitoes, such as used tyres and water-filled containers, should be strictly regulated or even reduced. If, however, an introduced vector or pathogen has inadvertedly become established, it should be eradicated as soon as possible. Mosquito invaders can be eradicated by draining water pools, application of insecticides, or use of biological larvicides. Pathogens can be eradicated by vector control, vaccination of infected people or livestock and isolation and treatment of infected hosts. Culling of infected livestock is another option. International agreements such as the Convention on Biodiversity and the International Health Regulations encourage preventive measures, and the world trade regulations allow restrictions on trade if and when the health of humans and animals is at stake. The ultimate policy goal would be to replace free trade by safe trade.