Development of guidelines for the surveillance of invasive mosquitoes in Europe

Abstract

Background: The recent notifications of autochthonous cases of dengue and chikungunya in Europe prove that the region is vulnerable to these diseases in areas where known mosquito vectors (Aedes albopictus and Aedes aegypti) are present. Strengthening surveillance of these species as well as other invasive container-breeding aedine mosquito species such as Aedes atropalpus, Aedes japonicus, Aedes koreicus and Aedes triseriatus is therefore required. In order to support and harmonize surveillance activities in Europe, the European Centre for Disease Prevention and Control (ECDC) launched the production of 'Guidelines for the surveillance of invasive mosquitoes in Europe'. This article describes these guidelines in the context of the key issues surrounding invasive mosquitoes surveillance in Europe.

Methods: Based on an open call for tender, ECDC granted a pan-European expert team to write the guidelines draft. It content is founded on published and grey literature, contractor's expert knowledge, as well as appropriate field missions. Entomologists, public health experts and end users from 17 EU/EEA and neighbouring countries contributed to a reviewing and validation process. The final version of the guidelines was edited by ECDC (Additional file 1).

Results: The guidelines describe all procedures to be applied for the surveillance of invasive mosquito species. The first part addresses strategic issues and options to be taken by the stakeholders for the decision-making process, according to the aim and scope of surveillance, its organisation and management. As the strategy to be developed needs to be adapted to the local situation, three likely scenarios are proposed. The second part addresses all operational issues and suggests options for the activities to be implemented, i.e. key procedures for field surveillance of invasive mosquito species, methods of identification of these mosquitoes, key and optional procedures for field collection of population parameters, pathogen screening, and environmental parameters. In addition, methods for data management and analysis are recommended, as well as strategies for data dissemination and mapping. Finally, the third part provides information and support for cost estimates of the planned programmes and for the evaluation of the applied surveillance process.

Conclusion: The 'Guidelines for the surveillance of invasive mosquitoes in Europe' aim at supporting the implementation of tailored surveillance of invasive mosquito species of public health importance. They are intended to provide support to professionals involved in mosquito surveillance or control, decision/policy makers, stakeholders in public health and non-experts in mosquito surveillance. Surveillance also aims to support control of mosquito-borne diseases, including integrated vector control, and the guidelines are therefore part of a tool set for managing mosquito-borne disease risk in Europe.

Figure 1

Aedes albopictus, female. Source: F.Schaffner/ECDC.

Figure 2

Procedures and main issues of invasive mosquito species and mosquito-borne disease surveillance in Europe. Green rounded rectangles show sources of information and alerts on risks for IMS and MBD that justify surveillance; part of it is performed within VBORNET, the European network of medical entomologists and public health experts (upper light green rectangle). These guidelines focus and develop the central part (central yellow rectangle). The left part is already addressed within the WHO guidelines (light blue rectangle), whereas the lower part is dealt with by the EMCA/WHO initiative on guidelines (dark blue rectangle). Blue rounded rectangles show procedures for surveillance (light blue) and control (dark blue) of IMS. Red rounded rectangles show procedures that are addressed within MBDs risk plans alongside IMS surveillance and control. WHO Guidelines (http://www.who.int/ihr/en): In the context of the application of the International Health Regulations (IHR 2005), WHO aims to strengthen national capacities by developing and updating guidelines and tools on vector surveillance and control. Thus, a web-based global point of entry (PoE) vector identification platform is under development, as well as a ‘Handbook on vector surveillance and control at points of entry’. This handbook focuses on actions that can be performed at PoE and on conveyances, containers, cargo, postal parcels and baggage. It considers all vector species (including mosquitoes) relevant to major MBDs. EMCA/WHO Guidelines: EMCA and WHO European Region have recently launched an initiative to develop ‘Guidelines for the control of invasive mosquitoes and associated vector-borne diseases on the European continent’, based on pan-European consultations. The first deliverable will be a strategy document with special emphasis on control issues.

Figure 3

Decision diagram for the implementation of surveillance of invasive mosquito species, in relation to mosquito-borne disease risk assessment and management. The large blue, orange and red rectangles show activities and decisions related to IMS surveillance, that are covered by the three scenarios used for defining the surveillance strategies described in the guidelines. Grey rectangles show activities and decisions to be implemented alongside IMS surveillance, within MBD risk plans, including surveillance of MBDs and control of IMS and MBDs. Depending on the MBD, indigenous mosquitoes may also be targeted.

Figure 4

Spread of the Asian tiger mosquito Ae. albopictus within Europe, 1995–2012. Red mapping units (territorial units for statistics NUTS 3) = presence; grey units = absence or no available information. The figure has been adjusted and updated compared to the figure given in the guidelines.

Figure 5

Known distribution of targeted invasive mosquito species by March 2013 (with details on countries and first reports in legend). Background map: distribution of Ae. albopictus (red: established; yellow: introduced, without confirmed establishment): First reports: Albania 1979, Italy 1990, spreading into 11 countries of the Mediterranean; localized in Bulgaria 2011; sporadic records without confirmed establishment in Belgium 2000 (not shown), The Netherlands 2005–2012, Germany 2007/2011/2012, Serbia 2009/2011/2012, Turkey and Russia 2011, Austria, Czech Republic and Slovakia 2012. Mapping units used are territorial units for statistics NUTS 3. ‘Absent’ (green colour) means that surveillance of mosquitoes has been implemented during the last 5 years without reports of introduction or establishment. Other colours: see legend on the map. Ae. aegypti (orange circles): Russia 2001, Portugal-Madeira 2004, Abkhazia and Georgia 2007, The Netherlands 2010 [eliminated: not shown]; Ae. japonicus, (blue circles): France 2000 [eliminated: not shown]), Belgium 2002 [localized], Switzerland and Germany 2008, Austria and Slovenia 2011; Ae. koreicus (white dots): Belgium 2008 [localized], Italy 2011. Not shown: Ae. atropalpus: Italy 1996 and France 2003 [eliminated], The Netherlands 2009-2011 [eliminated]; Ae. triseriatus France 2004 [intercepted].