Warming Europe Faces a New Epidemic Risk and Time Is Running Out

A 2026 review published in the International Journal of Environmental Medicine warns that warming, changing rainfall patterns and humidity are altering the distribution, seasonality and transmission dynamics of vector-borne diseases across Europe. The review, authored by Antonio Cristaldi, Salvatore Scondotto and Vincenzo Restivo of the University of Enna "Kore" in Italy, examines how climate change is reshaping risks from mosquito-, tick- and sandfly-borne diseases, including dengue, chikungunya, West Nile virus, Zika, malaria, leishmaniasis and tick-borne encephalitis.

According to the study, Europe can no longer treat many vector-borne diseases as distant or imported threats. The conditions that allow vectors to survive, reproduce and transmit pathogens are changing. Public health systems, sanitation strategies and climate adaptation policies must now move faster than the vectors themselves.

The Disease Map Is Moving

For decades, Europe's public health risk calculations were shaped by geography. Diseases such as dengue, chikungunya and Zika were largely associated with tropical and subtropical regions. Malaria was mostly viewed as an imported disease, but climate change is weakening those assumptions.

The review explains that vector-borne diseases are highly sensitive to temperature, precipitation and humidity. Rising temperatures are changing the geographical range and seasonality of mosquitoes and ticks, enabling disease transmission in areas that were previously less exposed.

The study notes that rising air temperatures have contributed to the northward and altitudinal expansion of Aedes albopictus, a mosquito species linked to dengue, chikungunya and Zika transmission. Aedes aegypti remains more geographically limited, largely around the Black Sea and eastern Mediterranean, but its presence still matters for future transmission risk.

Warmer seasons can lengthen vector activity, alter breeding patterns and raise the odds that imported infections become locally transmitted.

Dengue and Chikungunya Are Warning Shots

Dengue offers one of the clearest signs that Europe's risk profile is shifting. The review reports that autochthonous, or locally acquired, dengue transmission has increased substantially in Europe in recent years. Europe recorded 66 locally acquired dengue cases in 2022, rising to 122 in 2023. Italy reported 687 confirmed dengue cases by November 2024, including 213 autochthonous cases.

These numbers remain small compared with high-burden tropical regions, but the trend matters. Local transmission means the chain of infection is no longer confined to travelers returning from endemic countries. It means the local environment, vector population and human exposure patterns can support transmission.

Chikungunya sends a similar message. The review notes that Europe's first autochthonous chikungunya transmission occurred in Italy in 2007, resulting in 337 suspected cases and 229 laboratory-confirmed cases. More recently, Italy recorded 482 chikungunya cases in 2025, of which 384 were autochthonous, while France reported 809 locally acquired cases.

West Nile virus is already a recurring European concern. In 2023, 728 human cases were reported across the EU, including 709 locally acquired cases. Italy, Greece and Romania recorded the highest numbers, while deaths were reported in Italy, Greece, Romania and Spain. The review also notes that although total cases declined compared with 2022, the number of affected regions increased, suggesting wider geographic spread.

This is the new public health reality: Europe is not facing a single disease threat, but a shifting portfolio of climate-sensitive risks. Some, like West Nile virus and tick-borne encephalitis, are already established. Others, like dengue and chikungunya, are moving from imported risks toward episodic local transmission. Still others, including Zika, malaria and yellow fever, remain more limited but require sustained vigilance because the ecological conditions around them are changing.

Sanitation Is Climate Adaptation Now

The review insists that vector-borne disease control is not only a medical task. It is also an environmental sanitation, urban planning and governance challenge.

The biological pathway is straightforward. Higher temperatures can speed up vector life cycles and increase biting frequency. Rainfall creates standing water in containers, flood zones and urban debris. Drought can also raise risk by encouraging unsafe household water storage. Humidity helps mosquitoes survive longer and remain active, improving conditions for transmission.

The fight against vector-borne diseases begins well before hospitals see patients. It begins with drainage, waste collection, water storage, housing conditions, vector surveillance and public communication. Poorly managed urban environments can become breeding networks.

The review argues for integrated approaches that combine environmental management, biological and chemical control, physical protection, surveillance and community engagement. It highlights actions such as reducing stagnant water, improving waste management, maintaining drainage infrastructure and using entomological indicators such as ovitrap indices, adult mosquito density and larval positivity rates to guide early response.

Ministries of health cannot manage this threat alone. Municipal authorities, sanitation agencies, water departments, housing planners, climate scientists, border health authorities and local communities all have roles to play. A delayed response in one sector can become an outbreak in another.

The review also points to emerging technologies, including satellite remote sensing and climate-informed early warning systems. These tools can help identify when temperature, rainfall and vector patterns create higher outbreak risk. But technology will not be enough if local institutions lack response capacity or communities are not engaged.

Climate adaptation must now include mosquito and tick preparedness. Cities that invest in drainage, waste management, green infrastructure and early warning systems are not only adapting to heat and floods. They are reducing infectious disease risk.

Waiting Will Cost More Than Preparedness

Vector-borne diseases are not only a health threat; they are an economic risk. Healthcare systems already face growing costs from West Nile virus, tick-borne encephalitis, leishmaniasis and autochthonous dengue. Direct costs include diagnosis, treatment, hospitalization, surveillance and vector control. Indirect costs include productivity losses, long-term neurological complications and reduced workforce participation.

The risks extend beyond hospitals. Climate-sensitive vector-borne diseases can affect tourism, agriculture and local economies, especially in Mediterranean regions where seasonal mobility and outdoor labor are central to livelihoods. Investments in early warning systems, vector surveillance and public health infrastructure require sustained funding, but the review argues they can reduce long-term economic losses.

The equity dimension is just as important. The authors warn that rising temperatures and changing precipitation will exacerbate health risks, especially for socioeconomically disadvantaged populations. Poorer and more vulnerable areas may face higher vector exposure and weaker access to healthcare. Health facilities in resource-constrained settings may be overwhelmed by increases in infectious disease cases.

For the Global South, where urbanization, inadequate sanitation, climate vulnerability and limited health resources often overlap, the same dynamics may be more severe. Europe's experience is therefore not just a regional story. It is part of a wider climate-health transition in which disease preparedness, sanitation investment and climate resilience become inseparable.

The review is a narrative, not a systematic review, and the authors acknowledge possible publication bias, language bias and disparities across European countries in surveillance quality, diagnostic capacity, reporting systems and available epidemiological and entomological data. The authors caution that projections should not be treated as deterministic forecasts.