At the tip of an iceberg: citizen science and active surveillance collaborating to broaden the known distribution of Aedes japonicus in Spain

Roger Eritja,Frederic Bartumeus,Javier Lucientes,Sarah Delacour-Estrella,Ignacio Ruiz-Arrondo,Carlos Barceló,Miguel Á Miranda,Mikel A González,Ana L García-Pérez

doi:10.1186/s13071-021-04874-4

Abstract

BackgroundActive surveillance aimed at the early detection of invasive mosquito species is usually focused on seaports and airports as points of entry, and along road networks as dispersion paths. In a number of cases, however, the first detections of colonizing populations are made by citizens, either because the species has already moved beyond the implemented active surveillance sites or because there is no surveillance in place. This was the case of the first detection in 2018 of the Asian bush mosquito, Aedes japonicus, in Asturias (northern Spain) by the citizen science platform Mosquito Alert.MethodsThe collaboration between Mosquito Alert, the Ministry of Health, local authorities and academic researchers resulted in a multi-source surveillance combining active field sampling with broader temporal and spatial citizen-sourced data, resulting in a more flexible and efficient surveillance strategy.ResultsBetween 2018 and 2020, the joint efforts of administrative bodies, academic teams and citizen-sourced data led to the discovery of this species in northern regions of Spain such as Cantabria and the Basque Country. This raised the estimated area of occurrence of Ae. japonicus from < 900 km2 in 2018 to > 7000 km2 in 2020.ConclusionsThis population cluster is geographically isolated from any other population in Europe, which raises questions about its origin, path of introduction and dispersal means, while also highlighting the need to enhance surveillance systems by closely combining crowd-sourced surveillance with public health and mosquito control agencies’ efforts, from local to continental scales. This multi-actor approach for surveillance (either passive and active) shows high potential efficiency in the surveillance of other invasive mosquito species, and specifically the major vector Aedes aegypti which is already present in some parts of Europe.Graphical abstract

Highlights

Active surveillance aimed at the early detection of invasive mosquito species is usually focused on seaports and airports as points of entry, and along road networks as dispersion paths
As a result of this multiple-sourced Ae. japonicus surveillance deployment from 2018 to 2020 combining active surveillance and citizen science digital sampling tools, we describe here the first findings of Ae. japonicus populations in two new autonomous communities of Spain, Cantabria (2019) and all three provinces of the Basque Country (2020)
That report was administratively forwarded to the Vectornet network to update the European Centre for Disease Prevention and Control (ECDC) map reporting Cantabria as positive on an “introduced” status [25]

Summary

Introduction

Active surveillance aimed at the early detection of invasive mosquito species is usually focused on seaports and airports as points of entry, and along road networks as dispersion paths. In a number of cases, the first detections of colonizing populations are made by citizens, either because the species has already moved beyond the implemented active surveillance sites or because there is no surveillance in place. This was the case of the first detection in 2018 of the Asian bush mosquito, Aedes japonicus, in Asturias (northern Spain) by the citizen science platform Mosquito Alert. The species usually causes moderate nuisance to humans, especially in the vicinity of deciduous forests It is active during daytime and evening, and it is mostly exophilic but occasionally enters houses [7]. This species is able to withstand cold and snowy winters in the form of eggs or larvae [8]

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