Chikungunya, a painful mosquito-borne disease once mostly confined to tropical regions, could now be transmitted across large parts of Europe as rising temperatures caused by climate change allow the virus to survive in more places for longer periods, researchers warn.
A study published this month shows climate conditions suitable for transmission of the virus now extend from southern Europe into parts of central and northern countries on the continent, raising the risk of outbreaks during warmer months.
Scientists found infections could occur for more than six months each year in Spain, Portugal, Italy and Greece. In countries including France, Belgium, Germany and Switzerland, transmission may be possible for two to five months annually.
In south-east England, the virus could be spread for around two months each year.
The research, led by Sandeep Tegar at the UK Centre for Ecology and Hydrology, analysed data from 49 earlier studies to understand how temperature affects how the chikungunya virus develops inside the Asian tiger mosquito – an invasive species that has spread across Europe in recent decades.
The study found the minimum temperature needed for transmission is about 13-14C, lower than earlier estimates of 16-18C. That means the disease could spread across more regions and for longer periods than previously thought.
Chikungunya was first identified in Tanzania in 1952 and causes severe and prolonged joint pain. The disease can be fatal in young children and older adults.
France sees record spike in chikungunya cases as tiger mosquito spreads
Longer mosquito season
Outbreaks in Europe are often triggered when travellers return from tropical regions having been infected there and are then bitten by local tiger mosquitoes, transmitting the disease to them, which they in turn spread. Hundreds of cases were reported in France and Italy in 2025.
Cold winters have historically limited mosquito activity and acted as a natural barrier preventing the disease from spreading from one year to the next. Scientists say warming temperatures are now weakening that protection.
“We’re likely to see much bigger outbreaks because you don’t have this natural firebreak anymore,” said Steven White from the UK Centre for Ecology and Hydrology.
The study shows transmission across Europe is most likely between May and October, with peak risk in July and August, when roughly half the continent becomes suitable for the virus to spread.
Measuring the cost of mosquito bites
Health risks
Transmission in Europe is likely to become more visible over time, said Diana Rojas Alvarez, who leads the World Health Organization team on viruses transmitted by insect and tick bites.
Up to 40 percent of patients may experience arthritis or severe pain for years after infection, she said.
Rojas Alvarez urged preventative measures including removing standing water where mosquitoes breed, wearing protective clothing, using insect repellent and strengthening mosquito surveillance.
There have been no locally transmitted chikungunya infections reported in the United Kingdom, but 73 cases were recorded among travellers in the first half of 2025, almost triple the number reported during the same period in 2024.
The Asian tiger mosquito can transmit several viruses that cause serious illness, including chikungunya, dengue and Zika.
