Study finds painful tropical disease now being transmitted in Europe
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A new study has found that chikungunya, a painful mosquito-borne disease usually confined to tropical regions, can now be transmitted across much of Europe.
Rising temperatures linked to climate change have extended the period during which the virus can spread, making transmission possible for over half the year in countries such as Spain and Greece, and for around two months annually in parts of south-east England. Researchers warned that as global temperatures continue to rise, the disease is likely to move even further north.
The research is the first comprehensive assessment of how temperature affects the time chikungunya takes to develop inside the Asian tiger mosquito, a species that has spread across Europe in recent decades. Scientists found that the virus can incubate at temperatures about 2.5°C lower than previously believed, a difference they described as striking and alarming, The Guardian reported.
First identified in Tanzania in 1952, chikungunya was long restricted to tropical areas, where it causes millions of infections each year. The illness leads to intense and often long-lasting joint pain and can be life-threatening for young children and older people.
While only limited cases had been recorded in Europe in the past, large outbreaks involving hundreds of infections were reported in France and Italy in 2025, linked to travellers returning from overseas tropical territories such as Réunion.
The Asian tiger mosquito, which bites during the day, is steadily moving northward as Europe warms. Although it has been detected in the UK, it has not yet become established there. While vaccines exist, they are expensive, and avoiding mosquito bites remains the most effective protection.
The study explained that when a mosquito feeds on an infected person, the virus enters the insect’s body and, after an incubation period, reaches its saliva, allowing transmission to the next person it bites.
If the incubation period exceeds the mosquito’s lifespan, the virus cannot spread. Using data from 49 previous studies, the researchers calculated incubation times across a full range of temperatures for the first time.
They found that transmission is possible at temperatures between 13°C and 14°C, far lower than earlier estimates of 16°C to 18°C. This means southern European countries could face more than six months of transmission risk each year, while parts of central and western Europe could see several months of potential spread.
Until recently, cold winters had limited mosquito activity and helped prevent the virus from persisting between seasons. However, year-round mosquito activity is now being observed in southern Europe, raising concerns that chikungunya outbreaks will become more frequent and severe as the continent continues to warm.