Travelers planning vacations in Europe often focus on sunscreen, hydration, and a well-stocked first aid kit. According to travel medicine experts, another precaution increasingly deserves attention: protection against mosquito bites.

The German Society for Travel Medicine warned that the risk for mosquito-borne diseases in Europe should not be underestimated. Rising temperatures and changing climatic conditions allow invasive mosquito species and the pathogens they transmit to spread farther north across the continent.

Changing Patterns

For decades, dengue fever, chikungunya fever, and West Nile fever have been regarded primarily as diseases of tropical and subtropical regions. However, these infections are increasingly reported across Europe.

Experts attribute this trend largely to climate change. Milder winters, longer summers, and shifting rainfall patterns create favorable conditions for mosquito species that were once confined to warmer climates. The European Centre for Disease Prevention and Control (ECDC) has warned that mosquito-borne viral diseases are becoming increasingly established across Europe.

The Asian tiger mosquito (Aedes albopictus) has emerged as an important contributor to this trend. Native to Southeast Asia, the species has been established in numerous European countries over the past several decades and is considered an important vector for dengue, chikungunya, and Zika viruses.

Germany is now among the countries where mosquitoes have become permanently established, particularly in the southwestern regions and metropolitan areas such as Berlin.

Mediterranean Hot Spot

This trend is reflected in the surveillance data. France and Italy have reported increasing numbers of mosquito-borne infections over the years.

According to ECDC data, France reported 788 chikungunya cases, and Italy reported 384 cases in 2025, making it the worst year on record for chikungunya in Europe.

The ECDC also documented 27 locally acquired chikungunya outbreaks across Europe in 2025, which is a record for the continent. Of particular note was a locally transmitted case in Alsace, France, which is the northernmost documented local chikungunya infection in Europe.

Dengue Expansion

Experts are also observing an increasing shift toward Europe regarding dengue fever.

While local dengue outbreaks were still rare just a few years ago, European health authorities reported a significant increase in autochthonous transmission between 2021 and 2024. France alone has recorded 85 locally acquired dengue cases by 2024, the highest number reported to date.

By November 2025, the ECDC had documented an additional 29 locally acquired dengue cases in France and four in Italy.

This trend was driven by the rapid spread of Asian tiger mosquitoes. According to ECDC data, the species is now permanently established in 369 European regions compared with 114 regions a decade ago.

The tiger mosquito is currently established in 16 European countries, and its range continues to expand. New populations have recently been identified in Germany, Austria, Belgium, Switzerland, and Slovakia.

West Nile Established

Unlike dengue and chikungunya viruses, which have largely been introduced through travel-related cases, the West Nile virus (WNV) has already become established in Germany.

Since 2018, infections have been detected in birds and horses. The first locally acquired human infections transmitted by native mosquitoes were reported in 2019.

Regions in eastern Germany have been particularly affected. Experts at the Robert Koch Institute believed that the virus had become permanently established in Germany and could spread to other regions in the future.

The WNV differs from dengue and chikungunya because it is primarily transmitted by native Culex mosquitoes. As a result, local transmission already occurs independently of the spread of the Asian tiger mosquito.

Travel Precautions

Travel medicine specialists now recommend treating mosquito protection as an essential component of travel preparation, particularly for trips to Mediterranean destinations and other parts of southern Europe.

Recommended preventive measures include applying effective insect repellents to the exposed skin; wearing long-sleeved, light-colored clothing, particularly during the early morning and evening; and using mosquito nets and window screens. These measures can significantly reduce the risk for infection.

Vaccination may also play a role for some travelers. The Standing Committee on Vaccination now recommends chikungunya vaccination for certain high-risk groups traveling to areas experiencing active outbreaks or planning prolonged stays in endemic regions.

Protection After Travel

Individuals infected with dengue, chikungunya, or Zika virus may have pathogens in their bloodstream during the first few days after returning from travel. If such a person is bitten by a tiger mosquito, the virus can be transmitted to the mosquito and subsequently transmitted to other individuals.

For that reason, experts recommend that travelers returning from affected regions continue protecting themselves against mosquito bites for at least 2 weeks after their return.

The recommendation is intended to reduce the risk for local transmission. Health authorities have noted that the threat is no longer theoretical, given the established presence of the Asian tiger mosquito in several EU countries and its demonstrated ability to transmit the chikungunya virus and potentially other pathogens.

New Reality

The long-standing perception that tropical infectious diseases are limited to distant travel destinations no longer reflects the current epidemiology.

Experts have observed a steady expansion in both mosquito populations and the viruses that they transmit. As a result, Europe is gradually becoming a region with diseases such as dengue fever, chikungunya fever, and WNV infection.

For travelers, one message stands out: Mosquito repellents should be considered just as important as sunscreen and swimwear when packing for a vacation. Because diseases such as dengue fever, chikungunya fever, and West Nile fever have become more common in parts of Europe, consistently avoiding mosquito bites remains the most effective form of protection.

This story was translated from Medscape’s German edition.