Tropical virus invasion warning.
Diseases such as West Nile fever, yellow fever, dengue fever and Japanese encephalitis mostly occur in the tropics and other warm regions of the world.
But they are already becoming more widespread thanks to the greater movement of people, goods and animals.
Writing in The Lancet medical journal today, Professor Tom Solomon, from the University of Liverpool, and Dr Ernest Gould, from the Centre for Ecology and Hydrology in Oxford, said it was likely global warming would accelerate the spread of these viruses into southern and even northern Europe.
The invaders belong to a family of "flaviviruses" that are transmitted by bloodsucking insects.
One of them, the yellow fever virus, causes up to 30,000 deaths in sub-Saharan Africa each year.
There is no vaccine available against dengue virus.