A debilitating and painful tropical disease caused by infected mosquito bites is posing a greater threat to Europe, and could become established in the UK in the coming years.
In a new study, researchers have discovered that Asian tiger mosquitoes can spread the chikungunya virus when air temperatures are as low as 13C cooler than previously believed.
A current outbreak of the virus has caused the US to issue a warning for people heading to Seychelles, Bolivia and Suriname, urging them to get vaccinated before they travel.
It comes as new data shows the virus can now be transmitted across most of Europe. Sandeep Tegar, who led the study, said: “Europe is warming rapidly, and the tiger mosquito is gradually expanding northwards through the continent.”
The species, which is occasionally detected in south-east England, could become more prevalent across Britain as climate change causes temperatures to increase.
“The lower temperature threshold that we have identified will therefore result in more areas – and more months of the year – becoming potentially suitable for transmission,” Mr Tegar said.
In 2025, France and Italy saw record numbers of local outbreaks of chikungunya. The mosquito species has also caused a rise in the country’s dengue fever cases in recent years.
The researchers, from the UK Centre for Ecology and Hydrology, said the mosquitoes have started local outbreaks in Europe after biting people who have contracted the virus overseas.
New data shows that the possibility of infection is present for two to three months of the year across much of Europe, and up to six months in Spain and Portugal.
“Identifying specific locations and the months of possible transmission will enable local authorities to decide when and where to take action to reduce the risk or scale of outbreaks,” Mr Tegar said. “Our research could also help predict how climate change could influence the future spread of the chikungunya virus.”
Chikungunya is not typically a fatal disease, but it can cause excruciating long-term pain. The UK Health Security Agency describes the virus as “a sudden onset of fever usually accompanied by joint pain”.
Joint pains may last for months or longer, but other symptoms such as headaches, sensitivity to light and skin rashes usually subside within a few weeks.
In August, British travellers were urged to take precautions against mosquito bites during a rise in people returning to the UK with the virus.
Warmer weather creates better conditions for mosquitos to thrive and increases the rate at which the virus replicates and is transmitted.
There is currently a low risk of the virus in south-east England over the summer months. However, researchers warned that rising temperatures will increase the odds of the tiger mosquito establishing in the UK, as has happened elsewhere in Europe.
Scientists found eggs of the mosquito in a trap at a freight depot near Heathrow airport in October. The country saw its hottest summer on record last year and experts have warned of 2C of global warming by 2050.
The study’s senior author, Dr Steven White, said: “It is important that there is continued action to try to prevent the tiger mosquito from establishing in this country because this highly invasive species is capable of transmitting several infections that can cause serious health conditions including chikungunya, dengue and Zika viruses.”
The first known outbreak of the virus was in Tanzania in 1952. It now affects more than 110 countries across Asia, Africa, Europe and the Americas.
As of November 2024, around 480,000 cases of chikungunya have been detected, causing 190 deaths.
A vaccination is available, but can only be obtained privately through travel clinics or certain pharmacies in the UK.
