Policy

In cooperation with WHO headquarters, the European Centre for Disease Prevention and Control (ECDC), the European Mosquito Control Association (EMCA) and Member States, WHO/Europe is developing a regional framework for surveillance and control of invasive mosquitoes and re-emerging mosquito-borne diseases.

The goal is surveillance, prevention and control of diseases of public health importance that are transmitted by invasive species of mosquitoes, particularly dengue. Specific objectives are:

• to prevent the introduction and spread of invasive mosquitoes across the Region and their invasion of new territories;
• to prevent potential outbreaks of dengue and chikungunya and reduce the risk of their transmission in areas where invasive mosquitoes have become firmly established;
• to enhance entomological surveillance and monitoring of invasive species of mosquitoes;
• to improve disease surveillance and control; and
• to improve disease management to reduce morbidity and mortality due to dengue and chikungunya.

Background

The introduction, establishment and spread of invasive species of mosquitoes in the WHO European Region, aided by the globalization of trade and travel, raise serious concern. Exotic mosquitoes have been introduced and successfully established in new environments, where they can compete with native species, transmit pathogens to wild and domestic animals, and cause biting nuisance and irritation among human beings. Concern focuses mainly on the public health importance of invasive mosquitoes, however, owing to their role in the pathogen transmission, notably viruses of tropical origin, among vulnerable human populations.

Mosquitoes of the genus Aedes are able to disperse into new areas and adapt to new environmental conditions. In recent years, 6 species have been introduced into the Region, some of which have become firmly established and spread over large areas. The most important species, Aedes albopictus, has greatly expanded its range in past decades and is now firmly established in the Mediterranean basin. In its developmental stages, especially eggs, it is transported through the global trade in used car tyres and lucky bamboo plants. Also, adult mosquitoes may be transported in vehicles. A vector of human diseases, Ae. albopictus can survive periods of cold, and predictive models indicate that its range can expand northwards, especially in view of climate change.

A second species, Aedes aegypti, has become established around the Black Sea and in Portugal (Madeira). A highly effective vector of dengue and yellow fever viruses and closely adapted to human habitats, it could re-establish itself in most of southern Europe, but probably not further north, due to its intolerance of cold.

Several other invasive species have been recorded, including Ae. atropalpus, Ae. japonicus, Ae. koreicus and Ae. triseriatus. Some have been locally recorded and are spreading between countries, but they have not yet been implicated as important vectors of human diseases.