In almost all known epidemics and pandemics, pathogens have jumped from animals to humans and have been adapted to their organisms through evolutionary pressure. As humans penetrate deeper and deeper into natural habitats, the likelihood of such jumps increases. Climate change and increasing global mobility favour that infection vectors such as mosquitoes or ticks invade new regions and subsequently spread pathogens there. This is a global challenge for infection research and health prevention.
In Europe, for example, tropical viruses (arboviruses) transmitted by such vectors are becoming increasingly common. In recent years, there have been outbreaks of Chikungunya fever in the Mediterranean region, and the continuing spread of the Asian tiger mosquito increases the likelihood of dengue fever spreading. The tick-borne Crimean-Congo haemorrhagic fever virus has already successfully established itself in southern Europe. And West Nile virus has been causing annual cases of disease in birds, horses and humans since 2018, mainly in Greece and Romania, but also increasingly in Germany.