Practical management plan for invasive mosquito species in Europe: I. Asian tiger mosquito (Aedes albopictus)

Abstract

Aedes albopictus, also known as the “Asian Tiger Mosquito”, is an invasive mosquito species to Europe causing high concern in public health due to its severe nuisance and its vectorial capacity for pathogens such as dengue, chikungunya, yellow fever and Zika. Consequently, the responsible authorities implement management activities to reduce its population density, possibly to below noxious and epidemiological thresholds. In urban areas, these aims are difficult to achieve because of the species’ ability to develop in a wide range of artificial breeding sites, mainly private properties. This document (Management Plan) has been structured to serve as a comprehensive practical and technical guide for stakeholders in organizing the vector control activities in the best possible way. The current plan includes coordinated actions such as standardized control measures and quality control activities, monitoring protocols, activities for stakeholders and local communities, and an emergency vector control plan to reduce the risk of an epidemic.

Introduction

Globalization of trade and travel facilitate the spread of exotic species across the world. A considerable proportion of these species become established and cause severe environmental, economic and human health impacts. These species are referred to as invasive. As a long-time center for trade, Europe has seen the introduction and subsequent establishment of more than 11,000 non-native species, at least 15% of which are considered invasive and detrimental. Among the non-native terrestrial invertebrates in Europe, insects are the dominant group: of 1,522 established species, 1,306 (86%) are insects [1].

Regarding mosquitoes, several invasive mosquito species (IMS) have been inadvertently introduced into Europe, where they often find favorable environmental and climatic conditions, enhanced by climate change, for the establishment of permanent populations. These IMS, such as Aedes albopictus, Aedes aegypti, Aedes atropalpus, Aedes koreicus, Aedes japonicus and Aedes triseriatus have become an issue of primary importance in Europe as evidenced by the increasing number of detections in different countries and because of the public health risk related to the vectorial capacity of some of these mosquito species [2].

These IMS pose a considerable threat to both human and animal health because of their capacity to transmit diseases. In Europe, Aedes (Stegomyia) albopictus (Skuse 1894) (Diptera: Culicidae) has been responsible for the outbreak of chikungunya virus (CHIKV) in Northern Italy in 2007, in which about 250 people were infected [3,4], and in local transmissions of dengue virus (DENV), which were detected in Southern France and Croatia in 2010 and in Southern France in 2014 [5]. In 2017, two CHIKV outbreaks happened in Europe, one in Italy where four clusters displayed 298 autochthonous cases [6,7] and one in France [8] where a cluster of four confirmed autochthonous cases was detected.

There is growing concern now as both vectors and pathogens are reappearing in Europe after a long absence. For example, after decades of absence, Ae. aegypti occurs again along the Black Sea coast of Southern Russia, Georgia and Turkey [9]. Moreover, it has been the vector of the DENV type 1 epidemic in Madeira (Portugal) in 2012–2013, with about 2,000 recorded cases [10], and in 2017 it was found established in Fuerteventura (Canary islands, Spain) [11]. This species is an extremely efficient vector of DENV, being responsible for the most severe documented dengue epidemic in Europe which occurred from 1927 to 1928, when about 90% of the population of Athens were infected and more than 1,000 persons died [12]. In 2015–2016, there was an outbreak of Zika virus (ZIKV), which is spread primarily through the bite of Ae.aegypti or Ae. albopictus, in many regions of South America [13]. In Europe in 2019, the first autochthonous ZIKV case was recorded [14]. There is currently a dengue outbreak in the French Outermost Region of Réunion, sustained by Ae. albopictus [15].

Current models estimate some risks of mosquito-borne disease (MBD) outbreaks, with increasing risk linked to climate change impact [[16], [17], [18], [19], [20]]. Countries of the Mediterranean Basin are particularly exposed to MBD due to the high mosquito population densities and the extended seasonal period of mosquito activity [21,22].

Aedes albopictus is an invasive mosquito species which originated from the East Asian regions and has black and white stripes on its body and legs (Fig. 1). Aedes albopictus has spread across the world in the last few decades due to its ecological plasticity and human-mediated transport. Since its first detection in Albania in 1979 [23], Ae. albopictus has been found in many other European countries (see Fig. 2 for more details and references), as well as in the east and south of the Mediterranean Basin, in the Thrace region of Turkey, and on the eastern Black Sea coast [9,[24], [25], [26], [27]].