4.7% of Returning Symptomatic Europeans May Have Chikungunya, Dengue, and Zika Infections

A substantive study published in the Journal of Travel Medicine and Infectious Disease shows that arboviral infections caused by mosquito bites have risen in Europe over the past decades.

This systematic review and meta-analysis (Volume 64, March–April 2025) highlights the growing threat of chikungunya, dengue, and Zika viruses to international travelers and close contacts when returning home to Europe.

This meta-analysis, published online on January 10, 2025, of returning symptomatic travelers to Europe, showed a disease prevalence of 4.7%.

Most cases (55,924) were related to travel returning to southern European countries, while 2,796 (5%) were autochthonous (local).

Five countries reported autochthonous cases: France, Italy, Portugal, Croatia, and Spain.

France was the only country with autochthonous instances of all three arboviruses: chikungunya, dengue, and Zika. Additionally, various areas in France reported disease cases in 2024.

Meta-analyses estimating the prevalence of arboviral infections in a. pregnant women were included in the study. There were 59 cases of non-vector-borne transmission, primarily Zika-related sexual transmissions. 

From a mortality perspective, 19 related fatalities were reported, of which three were associated with chikungunya virus infection, 12 with dengue, and four with yellow fever. 

These European researchers wrote. 'The emergence of autochthonous (local) cases in Europe, the significance of imported cases from travelers ... underscore the need for proactive rather than reactive surveillance, targeted interventions, and collaborative efforts to prevent and control Aedes mosquito-borne infections in Europe.'

'Tailored approaches to disease management are important, as different viruses have different impact, sequelae, and areas of acquisition.... and mitigate their impact on public health and well-being.'

To prevent these diseases, public health agencies in the U.S., U.K., and Europe recommend international travelers speak with vaccine experts about available vaccines.

"Many European travelers may be unaware of newly released studies that show increased mosquito-borne illnesses occurring in southern Europe," Beverly Schaefer, RPh., a travel vaccine expert, at informed Vax-Before-Travel.

"Getting a dose of the chikungunya vaccine before travel would protect them from at least one of the diseases currently showing steadily increasing cases in Europe," added Schafer, with Katterman's Sand Point Pharmacy in Seattle, WA.

As of January 23, 2025, no Zika vaccines are available, and the supply of the second-generation dengue vaccine is minimal. However, the recently approved chikungunya vaccine is offered throughout Europe and the United States. Most travel clinics and pharmacies offer it.