Dengue and chikungunya may become epidemic diseases in Europe due to warming

 

Dengue and chikungunya fever could become widespread in Europe due to climate warming, which is fueling the spread of the tiger mosquito that transmits these diseases, as well as urbanization and mobility, warns a study published in The Lancet Planetary Health on Thursday.

Currently, four billion people in 129 countries are at risk of dengue or chikungunya, two diseases that were previously found mainly in tropical and subtropical countries, and whose main vectors are the yellow fever mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus).

The northward expansion of the tiger mosquito's range has been driven by global climate warming: as temperatures increase, their growth cycle becomes shorter, while the rate of virus reproduction in the insect increases as a result of temperature.

For the first time, the study published Thursday analyzes the links between the risk of dengue and chikungunya epidemics in Europe and a wide range of factors, including climate, environment, socioeconomic living conditions, demographics, and entomological data, over a 35-year period.

Funded by the Horizon Research and Innovation program, the study used data from the European Centre for Disease Prevention and Control, the World Health Organization, and publications on the presence of the tiger mosquito in Europe, from its arrival in 1990 to 2024.

Although the first outbreaks took more than 25 years to appear in Europe, the frequency and extent of dengue and chikungunya have continued to increase since 2010.

In 2024 alone, 304 cases of dengue were recorded, exceeding the 275 recorded in the entire previous 15 years. Local outbreaks were identified in four countries: Italy, Croatia, France, and Spain.

Nearly all cases (95%) were recorded between July and September, with three-quarters in urban or suburban areas, and the remaining quarter in rural areas.

The study showed that every one-degree increase in summer temperatures increases the risk of epidemics. Therefore, extremely hot summers "contribute significantly to this phenomenon," according to the authors of the research.

These trends indicate that "temperature remains an important factor in the risk of future epidemics, especially under extreme climate scenarios," and that "these diseases tend to become widespread across the European Union."