Scientists tracking the spread of dengue fever have named popular European holiday destinations they say are at risk from future outbreaks.
The disease is carried by Asian tiger mosquitos, which are becoming more common in Europe, including parts of southern France, Italy and Spain.
The mosquito was even spotted at the Paris Olympics this summer.
Dengue fever can cause severe muscle and joint pain – earning it the nickname “break-bone fever” – and in some cases can result in internal bleeding and death.
But until now, attempts to predict its spread haven’t been localised.
Now, a team led by the UK Centre for Ecology & Hydrology have developed a monitoring system that can predict outbreaks down to 10km accuracy.
“Sicily is a hotbed,” said Dr Steven White, a theoretical ecologist who worked on the study, adding that the locations around the Mediterranean basin are also “high-risk areas”.
He also pointed out multiple hotspots identified in southern Italy’s Puglia region and the Spanish city of Barcelona.
“If you’re going on holiday, you need to be careful because there are lots of these mosquitoes around,” he said.
“And there’s a higher risk you may pick up dengue from these places when you go on holiday.”
La Colle-sur-Loup, Baho, and Montpellier-Perols in southern France, and Vila-seca in Spain all had their first dengue outbreaks this year, which the modelling correctly predicted.
Dengue fever: What is it and how does it spread?
Last year, Paris had its first outbreak of the disease, making it the furthest north dengue fever has taken hold in Europe.
The mosquitos contract the virus by biting returning travellers who were infected while abroad and then transmitting it to other people in the area.
Southern France and northern Italy are high risk because of “a favourable climate, a stable mosquito population and the high number of travellers returning from tropical countries where the disease is prevalent,” according to Dr Dominic Brass, an epidemiological modeller at UKCEH who led the study.
“However, areas of risk are expanding northwards,” he said.
Scientists say warmer weather due to climate change is creating more favourable conditions for invasive mosquitoes to spread into previously unaffected areas.
In 2023, there were 130 locally acquired cases of dengue reported in the EU, compared to 71 in 2022, according to an update from the European Centre for Disease Prevention and Control (ECDC).
The rise is even more stark when you look back further – between 2010 and 2021, there were 73 cases across the whole period.
Asian tiger mosquito eggs have been found in southeast England, but the species has not yet become established in the UK.
However, the research team warned this is likely to change in the future as the UK feels the effects of climate change.
“It’s more of a question of when the mosquito establishes [in the UK], not if it’s going to happen,” said Dr White.
The UK Health Security Agency (UKHSA) warned last year that dengue fever could be transmitted in London by 2060, and the Asian tiger mosquito could become widespread across England in the 2040s.
Currently, there are no vaccines available in the UK that you can have to prevent dengue before travelling to a country where there’s a risk of infection, according to the NHS.