Public health guidance for assessing and mitigating the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA.
Date: 2025-07-03
Institutions: European Centre for Disease Prevention and Control
Subjects: European Economic Area, European Union, disease prevention, disease vector, health control, health risk, invasive species, risk management, substance of human origin, user guide, viral disease

PUBLIC HEALTH GUIDANCE

Public health guidance for 
assessing and mitigating the risk 
of locally-acquired Aedes-borne 
viral diseases in the EU/EEA

ECDC GUIDANCE 

Public health guidance for assessing and 
mitigating the risk of locally-acquired 
Aedes-borne viral diseases in the EU/EEA 

 
 
This report of the European Centre for Disease Prevention and Control (ECDC) was written and coordinated by 
Tamás Bakonyi, Principal Expert Vector-Borne and Zoonotic Diseases, Food-, Water-, Vector-borne and Zoonotic 
Diseases Section, One-Health-related Diseases Unit, ECDC. 

Contributing authors (in alphabetical order) 

External experts: Luisa Barzon (Department of Molecular Medicine, University of Padova, Italy), Clémentine Calba 
(Santé publique France, Marseille, France), Bruna Raquel Figueira Ornelas de Gouveia (Regional Health Directorate, 
Autonomous Region of Madeira, Funchal, Portugal), Antonios Michaelakis (Scientific Directorate of Entomology and 
Agricultural Zoology, Benaki Phytopathological Institute, Athens, Greece), Danai Pervanidou (Directorate for 
Epidemiological Surveillance and Intervention for Infectious Diseases, Hellenic National Public Health Organization, 
Athens, Greece), Chantal Reusken (Centre for Infectious Disease Control, National Institute for Public Health and 
the Environment, Bilthoven, the Netherlands), Flavia Riccardo (Department of Infectious Diseases, Istituto 
Superiore di Sanità, Rome, Italy), David Roiz (MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France), Javiera 
Rebolledo Romero (Sciensano, Brussels, Belgium), Lucía García Sanmiguel (Coordinating Centre of Sanitary Alerts 
and Emergencies, Ministry of Health, Madrid, Spain), María José Sierra Moros (Coordinating Centre of Sanitary 
Alerts and Emergencies, Ministry of Health, Madrid, Spain), Luciano Toma (Department of Infectious Diseases, 
Istituto Superiore di Sanità, Rome, Italy), Henriette De Valk (Infectious Disease Division, Santé publique France, 
Paris, France), Paula Vasconcelos (Public Health Emergencies Operations Centre, Directorate-General of Health, 
Lisbon, Portugal), and Christiane Wagner-Wiening (Baden-Wuerttemberg State Health Office, Ministry of Social 
Affairs, Health and Integration, Stuttgart, Germany. 

ECDC experts: Tamás Bakonyi, Olivier Briët, Céline Gossner, Joana Haussig, Nathalie Nicolay, Jenny Mohseni 
Skoglund and Jonathan Suk. 

The authors acknowledge the valuable comments of Mohammed Afzal (ECDC), Sabrina Bacci (ECDC), Martina Brix-
Zuleger (Ministry of Labour, Social Affairs, Health, Care and Consumer Protection, Vienna, Austria), Daniel Cauchi 
(ECDC), Áine Collins (ECDC), Sixtine Drougard (French National Agency for the Safety of Medicines and Health 
Products, Saint-Denis, France), Christina Frank (Department for Infectious Disease Epidemiology, Robert Koch 
Institute, Berlin, Germany), Helena de Carvalho Gomes (ECDC), Liese Van Gompel (ECDC), Phyo Myint (ECDC) and 
Imad Sandid (French National Agency for the Safety of Medicines and Health Products, Saint-Denis, France). 

Suggested citation: European Centre for Disease Prevention and Control. Public health guidance for assessing and 
mitigating the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA. Stockholm: ECDC; 2025. 

Stockholm, June 2025 

ISBN 978-92-9498-808-9 
doi: 10.2900/8091262 
Catalogue number TQ-01-25-038-EN-N 

© European Centre for Disease Prevention and Control, 2025 

Reproduction is authorised, provided the source is acknowledged 

ii 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Contents 

Abbreviations ............................................................................................................................................... iv 
Executive summary ........................................................................................................................................ 1 
Background and scope ................................................................................................................................... 3 
Key facts about Aedes-borne viral diseases ...................................................................................................... 4 
Aedes-borne viruses ....................................................................................................................................... 4 
Epidemiology of dengue, chikungunya virus disease and Zika virus disease in Europe ..................................... 5 
Laboratory diagnosis of Aedes-borne virus infections ................................................................................... 6 
Methodology of the guidance production .......................................................................................................... 8 
The risk matrix and suggested public health actions .......................................................................................... 9 
Definition of terms used to describe areas of transmission for Aedes-borne virus infection ............................... 9 
Risk levels: ............................................................................................................................................... 9 
Knowledge gaps and limitations .................................................................................................................... 23 
Pathogen-host interactions ...................................................................................................................... 23 
Diagnosis ............................................................................................................................................... 23 
Surveillance and response ....................................................................................................................... 23 
Prevention and treatment ........................................................................................................................ 23 
Vector ecology and vector management ................................................................................................... 23 
References .................................................................................................................................................. 25 
Annex 1.  .................................................................................................................................................... 28 

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Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

ECDC GUIDANCE 

Abbreviations 

ADE 

BSL 

CHIKV 

DENV 

DHF 

DSS 

ECDC 

EEA 

EIA 

ELISA 

EMA 

EQA 

EU 

Antibody-dependant enhancement 

Biology safety level 

Chikungunya virus 

Dengue virus 

Dengue haemorrhagic fever 

Dengue shock syndrome 

European Centre for Disease Prevention and Control 

European Economic Area 

Enzyme immunoassay 

Enzyme-linked immunoassay 

European Medicines Agency 

External quality assessment 

European Union 

EURL-PH-VBV 

European Reference Laboratory for public health on vector-borne viral pathogens 

EVD-Net 

Emerging and Vector-borne Diseases network 

IVD 

JEV 

NA 

NAAT 

NFP 

NITAG 

RT-PCR 

SoHO 

In vitro diagnostic 

Japanese encephalitis virus 

Not applicable 

Nucleic acid amplification test 

National Focal Point 

National Immunisation Technical Advisory Group 

Reverse-transcription polymerase chain reaction 

Substances of human origin 

VectorNet 

European network for medical and veterinary entomology 

WHO 

YFV 

ZIKV 

World Health Organization 

Yellow fever virus 

Zika virus 

iv 

 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Executive summary 

In recent decades, the epidemiology of mosquito-borne virus infections has been changing in several European 
countries. Locally acquired (i.e. autochthonous) cases of dengue, chikungunya virus disease and Zika virus disease 
have been reported in the Mediterranean regions of Europe. Between 2021 and 2024, the number of 
autochthonous dengue outbreaks and cases increased considerably. Intensive international travel has facilitated the 
importation of mosquito-borne viruses from endemic, tropical and sub-tropical areas while secondary, local 
transmission of the viruses from imported cases is predominantly driven by invasive Aedes mosquito species. 
Established populations of the Asian tiger mosquito (Ae. albopictus) have been reported in 13 countries in the 
European Union. The yellow fever mosquito (Ae. aegypti) has also been detected in parts of the European Union 
(e.g. Cyprus, Canary Islands (Spain) and Madeira (Portugal)). The summer weather conditions in recent years have 
been favourable for invasive Aedes mosquito propagation in European countries, and for the multiplication of 
Aedes-borne viruses in the vectors. Due to climatic changes, periods with favourable environmental conditions for 
the geographical spread and multiplication of invasive Aedes mosquitoes are expected to become longer. Warmer 
weather also facilitates the local transmission of viruses by these mosquitoes. Therefore, the risk of autochthonous 
outbreaks of Aedes-borne viral diseases is foreseen to increase in Europe. Meanwhile, the level of preparedness 
and experience with prevention and control of Aedes-borne viral disease varies in the European countries. This 
public health guidance provides information to support the assessment and mitigation of the risk of locally acquired 
Aedes-borne viral diseases for public health experts in the European Union/European Economic Area (EU/EEA). 

The guidance was produced following consultation with experts in this field. Public health experts were consulted 
from countries affected by autochthonous transmissions of Aedes-borne viral diseases (i.e. France, Italy, Portugal 
and Spain) and from at-risk countries with varying epidemiological situations (i.e. Belgium, Germany and Greece). 
In addition, laboratory experts, medical entomologists, and ECDC experts on emerging and vector-borne diseases, 
substances of human origin, and emergency preparedness and response support were involved in the production 
of the guidance. In April 2024, a workshop was organised during which the main principles of the guidance were 
developed. The workshop was followed by a written consultation with the experts involved. An advanced draft of 
the guidance was then shared with the National Focal Points from the Emerging and Vector-borne Diseases 
Network and the Substances of Human Origin – Blood Network for comments. 

The guidance provides key information on Aedes-borne viruses (particularly dengue virus, chikungunya virus and 
Zika virus), the principles of the laboratory diagnosis of these viruses and the epidemiology of Aedes-borne viral 
disease in Europe. Areas at risk of autochthonous, mosquito-borne transmission in the EU/EEA are divided into four 
risk levels (i.e. Level 1 to Level 4, and two sub-levels for Level 2 and 3). Areas without established vectors of 
Aedes-borne viruses are categorised as Level 1. Predisposed areas, where vectors of Aedes-borne viruses are 
established (i.e. there is evidence of over-wintering and reproducing populations of Aedes vectors), but where 
vector-borne transmission of the respective pathogen has not been detected in the current transmission season are 
categorised as Level 2. Within this level, two sub-levels were identified, depending on the receptivity and the 
vulnerability of an area. Receptivity is determined by the presence and density of Aedes vectors and other 
ecological and climatic factors favouring Aedes-borne virus transmission. Vulnerability is defined by the influx of 
infected travellers and the capacity of the health system to detect infections timely and deploy measures to prevent 
onward transmission. Predisposed areas with low receptivity and/or vulnerability (e.g. only locally established 
vectors, low vector density, unfavourable climate, low number of travellers from Level 3 and Level 4 areas) are 
considered to be Level 2a, whereas areas with medium to high receptivity and vulnerability are considered to be 
Level 2b. Areas which have experienced sporadic, autochthonous transmission in previous years are also 
considered to be at this risk level. Risk areas which are affected by autochthonous transmission of Aedes-borne 
viruses in the current transmission season are categorised as Level 3, with two sub-levels, depending on the 
number of outbreaks/clusters and the traceability of transmission chains. If there has been at least one confirmed 
autochthonous case of an Aedes-borne viral disease as a result of local and probable mosquito-borne transmission 
in the area during the current year, but the number of cases/clusters is considered to be low and transmission 
chains are traceable, the area is considered to be Level 3a. If the number of cases/clusters is considered to be 
high, involving overwhelming tracing capacity, the area is considered to be Level 3b. Endemo-epidemic areas, 
where autochthonous transmission of Aedes-borne viral diseases is not dependent on importation of the viruses, 
are categorised as Level 4.  

For each risk level the public health guidance outlines triggers for re-assessment, as well as relevant surveillance, 
prevention, preparedness, response and control actions (including laboratory preparedness, awareness raising and 
capacity building, multi-sectoral coordination and vector management activities). At Levels 1 and 2, public health 
actions focus on surveillance and prevention, while at Levels 3 and 4 more emphasis is placed on response and 
control measures. As risk levels are defined by the epidemiological, entomological and environmental conditions, 
triggers for re-assessment of categorisations are also specified in the document. Concise summaries of disease and 
entomological surveillance for Aedes-borne viral diseases and their vectors are also provided in the guidance, as 
well as explanations of the suggested prevention, preparedness, response and control actions. 

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Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

ECDC GUIDANCE 

The guidance has been developed on the basis of previous experience and currently applied practices in countries 
affected by locally acquired transmissions of Aedes-borne viral diseases in the EU/EEA. The measures applied are 
based on international and national guidelines against Aedes-borne viral diseases and general public health 
measures against mosquito-borne diseases. However, scientific evidence is often missing for the specificity, 
effectiveness and efficiency of the measures in the European context. The main gaps in knowledge and relevant 
topics for research are also discussed in the guidance. Links to further information on surveillance, preparedness 
and response (control) actions are provided in Annex 1. 

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Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Background and scope 

Human arboviruses carried by mosquito vectors in the Aedes genus are having a major public health impact in 
tropical and sub-tropical countries. Citizens of the EU/EEA are predominantly exposed to Aedes-borne virus 
infections during trips to countries or regions with active vectorial transmission of these viruses. Importations of 
Aedes-borne viruses to the EU/EEA by travellers are frequently reported. Until recent years, autochthonous (i.e. 
locally acquired) cases associated with vector-borne transmission from imported cases were rarely reported. 
However, the geographical distribution of the Asian tiger mosquito (Aedes albopictus) has extended considerably in 
Europe in recent decades, and the environmental and ecological parameters (average temperature in summer 
months, mosquito abundance) may provide favourable conditions for local, mosquito-borne transmission of Aedes-
borne viruses from imported cases. 

Increasing numbers of autochthonous dengue cases have been reported in recent years in some western/southern 
European countries, indicating a growing threat to public health in the EU/EEA. ECDC aims to support the EU/EEA 
countries in strengthening their surveillance, prevention and control activities against autochthonous transmission 
of Aedes-borne viral diseases (dengue, chikungunya virus disease and Zika virus disease). This public health 
guidance is intended to support the assessment of the risk of locally acquired Aedes-borne viral diseases and 
suggest suitable public health actions and activities for prevention and control. The scope of the public health 
guidance is to: 

• 

• 
• 
• 

• 

provide concise descriptions of the most important Aedes-borne viruses and the epidemiological situation 
for Aedes-borne viral diseases in the EU/EEA; 
describe risk levels for transmission of Aedes-borne virus infection in different geographical areas; 
provide concise descriptions of the suggested surveillance, prevention and control measures; 
describe limitations of the guidance, missing scientific evidence, gaps in knowledge and topics for 
operational research; 
provide links to relevant documents on public health activities to counteract Aedes-borne viral diseases. 

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Key facts about Aedes-borne viral diseases 

Aedes-borne viruses 
The term ‘Aedes-borne viruses’ refers to a broad ecological/epidemiological category of different arboviruses that 
are transmitted by mosquitoes in the Aedes genus. Due to the high diversity of Aedes mosquito species globally 
and the arboviruses detected in them, there are many viruses in this category. The detection of an arbovirus in an 
Aedes vector, or even the demonstration of the ability of a vector species to transmit a defined virus in laboratory 
experiments (vector competence) cannot be considered as evidence for a vectorial role in natural (field) conditions. 

This public health guidance focuses on three diseases (dengue, chikungunya virus disease and Zika virus disease) 
caused by Aedes-borne viruses that are not endemic in EU/EEA countries on the European mainland, even though 
local outbreaks connected to autochthonous, mosquito-borne transmission have been reported in some countries 
and further outbreaks are expected in the coming years. 

Dengue virus (Orthoflavivirus denguei, DENV) is the causative agent of dengue, which is the most widespread 
mosquito-borne viral disease affecting humans worldwide. Although up to 80% of all dengue infections can remain 
asymptomatic, commonly reported clinical symptoms include acute, high fever, headache, myalgia, arthralgia, 
maculopapular rash and haemorrhage. A portion of cases (usually <5%) can be severe and these are commonly 
referred to as ‘dengue haemorrhagic fever/dengue shock syndrome (DHF/DSS)’. Severe dengue is characterised by 
an increase in vascular permeability that can lead to life-threatening hypovolemic shock. A fraction of DHF/DSS 
cases may be fatal (particularly in children and adolescents). DENV has four distinct serotypes. Immunity to any of 
the four serotypes is probably life-long, but this does not confer protective immunity to the other three serotypes. 
Subsequent infection by a different DENV serotype may contribute to the development of DHF/DSS through 
antibody-dependant enhancement (ADE), potentially together with host and virus genetic factors and host 
comorbidities. The median incubation period for dengue is 5.6 days (3–14 days) [1]. Viraemia reaches high titres 
two days before the onset of symptoms, and it is generally high enough to infect mosquitoes for the next six days 
[1,2]. In addition, people who are infected with DENV without developing clinical symptoms are also infectious to 
mosquitoes [2-4].  

Humans are the main amplifying host of the virus. Although bites from infected mosquitoes are the predominant 
mode of transmission, non-vectorial transmissions (e.g. nosocomial, sexual, intrapartum, perinatal and 
mucocutaneous transmission, as well as transmission through breastfeeding, occupational (medical/laboratory), 
blood transfusion, bone marrow transplant and organ transplant) have also been reported [5]. Non-human 
primates may be involved in the sylvatic cycle of dengue in south-eastern Asia, western Africa and South America 
[6]. The virus circulates between humans in rural and urban areas. The primary vectors are the yellow fever 
mosquito (Aedes aegypti) and the Asian tiger mosquito (Aedes albopictus). According to laboratory experiments, 
the time required for the mosquito to become infective after feeding on a viraemic host (i.e. the extrinsic 
incubation period), is about ten days at 27°C (but longer at lower temperatures). The optimal daily mean 
temperature for dengue virus transmission by Ae. albopictus in temperate zones of the northern hemisphere 
is  24–26°C; however, transmission can occur within the temperature range of 12–30°C [7,8]. Dengue is endemic 
in more than 100 countries in Africa, the Americas, South and South-east Asia, and the Western Pacific region 
[9,10]. Dengue viruses are often transported by infected travellers. All four serotypes now co-circulate in many 
places in the world. The number of dengue cases has been increasing considerably over the past few decades, and 
large outbreaks have been reported [9]. Imported cases of dengue are frequently reported in travellers returning to 
the EU from endemic areas [11-13]. These may generate local, mosquito-borne transmission events in non-
endemic areas where competent vectors are present, and the climatic/weather conditions support virus 
multiplication in them [14-16]. 

Chikungunya virus (Alphavirus chikungunya, CHIKV) has three major genetic lineages and, until the spread of the 
East-Central-South African serotype to Asia in 2006 and the Asian type into the Americas in 2013, these three genetic 
lineages reflected the geographical distribution of the virus (West Africa, East-Central-South Africa and Asia). Up to 
28% of CHIKV infections remain asymptomatic [17], but in most cases the disease is characterised by a sudden onset 
of fever, chills, headache, myalgia, nausea, photophobia, incapacitating joint pain and petechial or maculopapular rash 
which develops 3–7 days (1–12 days) after infection [18]. Recovery after the acute phase (about 10 days) is common, 
typically resulting in a life-long immunity against subsequent CHIKV infections [18]. However, the chronic form of 
CHIKV disease, characterised by recurrent joint pain, may develop in about 5−80% of cases [18]. General 
complications are rare and include myocarditis, hepatitis and ocular and neurological disorders. Risk factors for more 
severe disease include intrapartum infection during the perinatal weeks for the neonates, advanced age (>65 years) 
and co-morbidities. In the elderly, arthralgia can evolve to a chronic rheumatoid arthritis syndrome. 
Meningoencephalitis affects primarily neonates. The reported average case fatality for CHIKV disease is low, however, 
excess mortality temporarily associated with different CHIKV disease outbreaks has been observed [19]. Humans are 
the major vertebrate hosts of CHIKV worldwide, although in Africa and Asia wild primates can also be included in the 
transmission cycle. The main vectors of CHIKV to humans are the Ae. aegypti and Ae. albopictus mosquito species. 

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ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Mutations in the E1 and E2 glycoproteins of CHIKV can affect viral fitness for dissemination by Ae. albopictus [20]. 
Virus titres in the blood of humans can be very high at the beginning of the illness, lasting for around six days (three 
to 10 days) [21]. Viraemic humans (both symptomatic and asymptomatic) can infect mosquitoes feeding on them. 
The extrinsic incubation period varies between two and 15 days [22]. Mother-to-child transmission has also been 
reported in women who developed the disease within the final week prior to delivery. There is no evidence that the 
virus is transmitted through breast milk. Transmission of chikungunya virus through transfusion and transplantation 
has not been reported, but asymptomatic blood donors with high titre viraemia have been detected through CHIKV 
nucleic acid amplification test (NAAT) screening [23,24]. 

Zika virus (Orthoflavivirus zikaense, ZIKV) has two genetic lineages: the African lineage and the Asian lineage. 
Over the last two decades, the geographical distribution of ZIKV has expanded to new areas in the Pacific and the 
Americas. Humans infected with ZIKV often remain asymptomatic. However, infections can manifest as ZIKV 
disease after 3–10 days of incubation [25]. ZIKV disease usually involves a short (2–7 days) and self-limiting illness 
with typically mild symptoms of maculopapular rash, with or without mild fever, arthralgia, fatigue, non-purulent 
conjunctivitis/conjunctival hyperaemia, myalgia and headache [25]. However, among women infected during 
pregnancy, congenital central nervous system malformations of the foetus (such as microcephaly) and foetal losses 
were notified during several recent ZIKV disease outbreaks [26]. Unusual increases of Guillain–Barré syndrome 
incidence, coinciding with the ZIKV disease outbreaks, were reported in several countries in the Americas and in 
French Polynesia [25]. Although serological surveys in Africa and Asia have detected specific antibodies in various 
animal species, no animal reservoir for ZIKV is known in Europe. Globally, Ae. aegypti is the main vector of ZIKV, 
but other Aedes species can also transmit the virus. The role of Ae. albopictus as vector was evidenced by the 
autochthonous transmission of ZIKV in France in 2019 [27]. Asymptomatic infected humans develop viraemia levels 
that might infect mosquitoes, however the susceptibility of Ae. albopictus and Ae. aegypti lines to ZIKV strains can 
vary. The extrinsic incubation period (i.e. the time interval between a mosquito feeding on virus-infected blood and 
shedding the virus through its saliva) varies between five and 24 days, depending on temperature and vector 
species. Beyond vector-borne transmission, maternal-foetal transmission can also occur, most probably by trans-
placental transmission and during delivery, when the mother is infected. Sexual transmission has also been 
documented in several instances [26]. It is also suspected that ZIKV can be transmitted through transfusion of 
blood or blood components [28]. 

Epidemiology of dengue, chikungunya virus disease and Zika 
virus disease in Europe 
To date, dengue, chikungunya virus disease and Zika virus disease are not endemic in mainland EU/EEA and the 
vast majority of the cases are reported among travellers infected in endemic countries in the tropics and sub-
tropics. However, when the environmental conditions are favourable, in areas where the competent vectors are 
established, viraemic travel-related cases may lead to local transmission of the virus. The probability of local 
transmission after importation events depends on the abundance and activity of the Ae. albopictus and Ae. aegypti 
population (which varies seasonally and itself depends on factors such as human population density, the availability 
of water-holding containers for the development of the aquatic mosquito larvae, rainfall and temperature). It also 
depends on protective measures (such as protection against mosquito bites and other mosquito control measures), 
and temperature, which governs the speed of reproduction of the viruses inside the mosquitoes (see section 
entitled ‘Aedes-borne viruses’). 

From 2010 to 2024, 579 autochthonous cases of dengue were reported in mainland EU/EEA involving transmission 
by Ae. albopictus, with an increasing number of outbreaks occurring in the most recent years (71 cases in 2022, 
130 cases in 2023 and 304 cases in 2024) [14]. These cases were reported by Italy (305), France (240), Spain 
(24) and Croatia (10). 

From 2007 to 2024, 861 autochthonous cases of chikungunya virus disease were reported in mainland EU/EEA. 
These cases were reported by Italy (829) and France (32) [29,30]. 

From 2016 to 2024, three autochthonous Zika virus disease cases transmitted through local mosquito bites were 
reported by France (Hyères city, Var department) [27]. 

Dengue, chikungunya virus disease and Zika virus disease are notifiable at EU level and therefore surveillance is 
compulsory in EU/EEA countries. The surveillance system adopted can vary, depending on the probability of virus 
activity and resources available [31]. 

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ECDC GUIDANCE 

Laboratory diagnosis of Aedes-borne virus infections 
The recommended and preferred laboratory diagnostic tests for the detection of Aedes-borne virus infections 
depend on several factors, including: i) the clinical information and case history, ii) the available specimen (e.g. 
blood/plasma, urine, saliva, cerebrospinal fluid, amniotic fluid, semen, and breast milk), and iii) the capabilities of 
the laboratory. 

In the acute stage of infection, the direct detection of the virus or its components (i.e. nucleic acid and/or 
antigens) can be attempted. Molecular assays, particularly nucleic acid amplification by reverse-transcription 
polymerase chain reaction (RT-PCR) (using various platforms) are the most widely used methods for the detection 
of viral RNA in diagnostic samples. The advantage of RT-PCR-based techniques are the high sensitivity, high 
specificity, rapidness and availability/easy set-up in most laboratories. Beyond potential test sensitivity or specificity 
issues connected to sequence diversity of the target viruses, probably the most important limitation of molecular 
tests is that the presence of the virus in the patient is limited in time and may rapidly decrease below detection 
limits during the course of the infection. Therefore, the diagnostic window is usually five to seven days after the 
disease onset of dengue, chikungunya virus disease or Zika virus disease. However, it also depends on the type of 
specimen (e.g. DENV RNA is detectable in urine for a longer period than in blood and ZIKV RNA has been detected 
in semen samples several weeks after infection). In general, the positive result of a molecular test is highly 
informative and allows case confirmation, but the negative predictive value of such tests is low, especially during 
later phases of infection.  

The subsequent determination of a partial or complete genome sequence of the virus(es) in the specimen is 
encouraged for the identification of genotype/serotype, molecular epidemiology and test result confirmation/validation 
purposes. Tests for the detection of DENV non-structural protein 1 (NS1) antigen in blood by immunochromatographic 
or enzyme immunoassay techniques are also used for direct diagnosis in patients with acute infection. The isolation of 
Aedes-borne viruses (e.g. in cell cultures) is not used in routine diagnostics nowadays (due to the long turn-around 
time and extensive resources required − e.g. BSL-3 laboratory facilities), however, subsequent isolation of viruses 
from a positive clinical specimen is encouraged for reference and research purposes. 

The indirect diagnosis of Aedes-borne virus infections is based on the demonstration of the immune response to 
the virus antigens, most frequently through the detection of anti-viral antibodies in samples. Several platforms and 
assays are available, including ELISA tests, immunofluorescence assays, and chemiluminescence immunoassays for 
the detection of virus-specific IgM and IgG antibodies in serum or plasma. The overall advantage of serological 
tests is the wide diagnostic window, as antibodies may persist for several weeks or months after infection. The 
timing of the infection can be estimated through the detection of different immunoglobulin types (e.g. IgM and IgG 
antibodies), the determination of the antibody titres, the determination of antibody kinetics in paired sera (e.g. 
seroconversion) or antibody avidity tests. However, the accurate determination of the time of infection is often 
challenging if only serological data are available. One of the main disadvantages of serological tests for the 
diagnosis of Aedes-borne virus infections is the cross-reactivity between related viruses. DENV and ZIKV have 
antigenic structures of viral proteins similar to other viruses in the Orthoflavivirus genus. For the diagnosis of 
autochthonous infections in Europe, cross-reactions with endemic viruses in the area, particularly West Nile virus, 
Usutu virus and the tick-borne encephalitis virus, should be taken into consideration.  

For imported cases, further orthoflavivirus infections (e.g. yellow fever virus (YFV) and Japanese encephalitis virus 
(JEV)) should be excluded. Antibodies against CHIKV may also cross-react with other alphaviruses (e.g. Sindbis 
virus), which may influence test specificity, however, serological cross-reactivity between alpha and flaviviruses is 
not expected. The different serological methods vary in specificity. The ‘gold standard’ for the determination of 
serotype-specific antibodies is usually the virus neutralisation test (or plaque reduction test), simultaneously 
performed on the serum sample with potentially cross-reacting viruses. However, it can be challenging to perform 
such tests in some laboratories, due to technical capabilities (e.g. access to BSL-3 laboratory facilities, availability of 
viruses, cell lines) and capacities. Previous infections or immunisations (e.g. vaccinations against tick-borne 
encephalitis, yellow fever, dengue or Japanese encephalitis) should also be taken into consideration during the 
interpretation of serological results. 

Diagnostic test kits (with CE label) for the most important Aedes-borne viruses (e.g. CHIKV, DENV, YFV, ZIKV) are 
marketed in the EU/EEA; however, availability may vary. Careful planning of procurements and stockpiling can 
ensure sufficient supply of in vitro diagnostics (IVDs). Some laboratories may use assays developed in-house. The 
IVDs should comply with the regulation (EU) 2017/746 on in vitro diagnostic medical devices [32]. Laboratory 
diagnostic capabilities for the above-mentioned diseases should be developed and maintained irrespective of the 
risk levels. The European Reference Laboratory for public health on vector-borne viral pathogens (EURL-PH-VBV) 
provides support for the development and maintenance of laboratory diagnostic capabilities on Aedes-borne viruses 
(e.g. provision of laboratory guidelines, protocols, reference materials, confirmatory services and training) to the 
EU/EEA countries. Diagnostic capabilities should be regularly monitored through quality assurance and external 
quality assessments (EQAs). 

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Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

The demand for laboratory diagnostic tests may rapidly increase during an outbreak. Therefore, the preparedness 
and response plan should describe procedures for the allocation of resources to ensure, and – in case of an 
upsurge in requirements – laboratory capacities. Protocols for sample collection, testing and timely reporting 
should be specified (including the financing of laboratory tests). 

Regular communication between general practitioners, specific clinics (e.g. infectious disease clinics, vector-borne 
disease clinics, travel medicine clinics), hospitals, public health departments and laboratories are essential to 
understand the rationale behind the choice of the laboratory diagnostic method, the availability of assays and the 
expectations and limitations of test results. In outbreak situations, communication and coordination between 
clinicians, virologists, epidemiologists and crisis managers should be enhanced. 

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Methodology of the guidance production 

The number of published scientific reports on public health actions in the context of autochthonous, vector-borne 
transmissions of Aedes-borne viruses in the EU/EEA is low. This public health guidance is based on the knowledge 
and experience of topic experts from the EU/EEA. Experts have been invited to contribute on the basis of their 
independent scientific capacities. ECDC’s National Focal Points for Emerging and Vector-borne Diseases (NFPs) from 
four countries with autochthonous transmission of Aedes-borne viruses (France, Italy, Portugal and Spain) were 
consulted to identify two national experts to be involved in the development of the guidance. For the 
representation of at-risk countries with different epidemiological situations and risk levels, experts were also invited 
from three other countries (Belgium, Germany and Greece, one expert from each) to help develop the document. 
To obtain state-of-the-art information on the virological and laboratory diagnosis aspects of Aedes-borne virus 
infections, two virology laboratory experts were invited, as well as two medical entomologists to provide expert 
opinions on the vector monitoring, management and control issues. All the experts invited provided declarations of 
interest, which were assessed for conflict of interest according to ECDC’s policy on scientific integrity and 
independence [33]. No conflicts of interests were identified for the participants. 

A workshop was organised on 16−18 April 2024 at ECDC (Solna, Sweden) where the aforementioned experts and 
ECDC’s own experts discussed the content of the public health guidance. A draft risk matrix table was developed 
and shared with the participants prior to the workshop. The input from the experts at the workshop was included 
in the draft risk matrix, which was subsequently reviewed by the meeting participants. The other parts of the 
guidance were drafted by ECDC experts in consultation with the external experts, based on published scientific 
papers, national and international reports, protocols and guidelines. 

The draft public health guidance was submitted for a stakeholder consultation between 14 June and 14 September 
2024. The document was shared with the NFPs of the EVD-Net and with the NFPs in the Blood group of the 
Substances of Human Origin (SoHO) network. The input obtained through the stakeholder consultation was 
included in the final version of the guidance. 

8 

 
 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

The risk matrix and suggested public health actions 

Definition of terms used to describe areas of transmission 
for Aedes-borne virus infection 

Risk levels  

Four risk levels (Level 1 to Level 4, and two sub-levels for Levels 2 and 3) for transmission of Aedes-borne viruses 
are defined in a risk area. For each risk level the guidance outlines the relevant surveillance activities, prevention 
and control measures. 

Definition of terms  
• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

A risk area is a geographical area where individuals are exposed to the risk of being infected with locally 
acquired Aedes-borne pathogens. 
Introduction of a vector is any detection of a vector species in the environment in any area where the 
vector has not been established.  
Established status of vectors is attributed when a population of mosquitoes has been observed over-
wintering and reproducing locally in the environment within or near the same locality in at least one 
municipality within the risk area. Evidence for an established population of the species is the presence of 
the insect (at any life stage) in the outdoor environment before the coldest month of the year, and of living 
immature stages or a growing adult population thereafter. 
The mosquito transmission season for Aedes-borne viruses mainly depends on environmental factors, in 
particular temperature. The optimal daily average temperature for dengue and chikungunya virus 
transmission in temperate zones of the northern hemisphere is 24–26°C for Ae. albopictus and 28–29°C for 
Ae. aegypti. However, transmission can occur within the temperature range of 12–30 C for Ae. Albopictus 
and 13–34°C for Ae. aegypti [7,8]. 
Receptivity of a risk area is determined by the presence and density of Ae. albopictus and/or Ae. aegypti 
and other ecological and climatic factors favouring Aedes-borne virus transmission. 
Vulnerability of a risk area is defined by the influx of infected travellers and the capacity of the health 
system to timely detect infections and deploy measures to prevent onward transmission. 
Laboratory capacity for Aedes-borne viral infections refers to the ability of EU/EEA laboratories to handle 
the volume of diagnostic testing, surveillance testing, and research activities required to manage and 
control outbreaks.  
Laboratory capabilities for Aedes-borne viral infections refer to the range and complexity of diagnostic 
tests, surveillance, and research methodologies that EU/EEA laboratories can perform to detect, identify and 
study these infections. 
Monitoring consists of procedures implemented for temporary or continuous observation (e.g. of species 
dynamics) and is not followed by any additional activities. 
Surveillance consists of procedures developed in response to a risk and carried out to support subsequent 
actions. 
Haemovigilance refers to a set of organised surveillance procedures relating to serious adverse or 
unexpected events or reactions in donors or recipients, and the epidemiological follow-up of donors 
(according to Directive 2002/98/EC) [34]. It covers the entire transfusion chain, from the donation and 
processing of blood and its components to their provision and transfusion to patients and their follow-up. It 
includes the monitoring, reporting, investigation and analysis of adverse events related to the donation, 
processing and transfusion of blood, and actions taken to prevent their occurrence or recurrence. 
Biovigilance extends the term haemovigilance beyond blood to incorporate monitoring of adverse events 
and reactions associated with other substances of human origin (SoHO), such as tissue, organs, and cells 
used for transplantation [35]. It should be noted that for this guidance, having systems in place for 
haemovigilance and biovigilance does not imply routine testing for Aedes-borne viruses in SoHO.  

Risk Level 1: An area without established vectors is a risk area where Ae. albopictus and/or Ae. 
aegypti are not (yet) established and autochthonous vector-borne transmission of Aedes-borne viral 
diseases has never been detected. 
Risk Level 2: A predisposed area is a risk area where Ae. albopictus and/or Ae. aegypti are established 
but where vector-borne transmission of the respective pathogen has not been detected in the current 
transmission season. The risk for vector-borne transmission in predisposed areas is influenced by the 
receptivity and vulnerability of the area.  
− 

Risk Level 2a: Predisposed areas with low receptivity and/or vulnerability (e.g. only locally 
established vectors, low vector density, unfavourable climate, low number of travellers from Level 3 
and Level 4 areas). 

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Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

ECDC GUIDANCE 

− 

Risk Level 2b: Predisposed areas with medium to high receptivity and vulnerability (e.g. widely 
established vectors, high vector density, favourable climate, high number of travellers from Level 3 
and Level 4 areas). Areas with sporadic, autochthonous transmissions in the previous years are also 
included in this risk level.  

Classifying areas into Level 2a or 2b can be challenging, because both receptivity and vulnerability may vary 
markedly on the local scale (depending on factors such as population density and land-use), and it is difficult to 
define a clear threshold between low and medium (or medium and high) receptivity, and between low and medium 
(or medium and high) vulnerability. Furthermore, these indicators vary strongly on a seasonal basis.  

In this guidance, it is advised to spatially differentiate between Levels 2a and 2b at the (lowest) spatial resolution 
for which it practically makes sense to differentially apply the recommended actions, and to consider the highest 
seasonal risk (e.g. that of the (late) summer months when mosquito biting densities are at their highest, extrinsic 
incubation periods are shortest and many travellers are returning from summer holidays in affected destinations) in 
order to differentially classify an area into Level 2a or 2b. 

• 

• 

Risk level 3: An affected area is a risk area with autochthonous transmission of Aedes-borne viruses in 
the current transmission season. Two types of affected areas are differentiated according to the number of 
outbreaks/clusters and the traceability of transmission chains: 
− 

Risk Level 3a: There has been at least one confirmed autochthonous case of an Aedes-borne viral 
disease as a result of local mosquito-borne transmission in the area during the current year. 
However, the number of cases/clusters is considered to be low and transmission chains are 
traceable. 
Risk Level 3b: The number of cases/clusters is considered to be high and this is overwhelming 
tracing capacity. 

− 

Risk Level 4: An endemo-epidemic area is a risk area where autochthonous transmission of Aedes-
borne viral diseases is not dependent on importation of the viruses (i.e. over-wintering of viruses). In 
addition, introduction of additional, exotic viruses or strains may also initiate local outbreaks. 

Summary of risk area characteristics 

Risk 
Level 

Risk area type 

Vector 
established 

Autochthonous 
transmission during 
the current season 

1 

2 

3 

4 

Area without established 
vectors 

Predisposed area 

Affected area 

Endemo-epidemic area 

No 

Yes 

Yes 

Yes 

No 

No 

Yes 

Yes 

Presence of 
Aedes-borne 
viruses all over 
the year 
No 

No 

No 

Yes 

10 

 
 
•
•
•

•

ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Public health activities at different risk levels 

Risk level 1 - Area without established vectors 

Description and triggers for re-assessment 
•

Ae. albopictus or/and Ae. aegypti are not established in the area (but may be/have already been
introduced).
Public health actions focus on surveillance of imported cases and mosquito vectors.
Re-assessment frequency: annual.
Re-assessment triggers: establishment of Ae. albopictus or/and Ae. aegypti (according to vector surveillance
data). → Move to Risk Level 2a.

Public health actions and interventions 
Disease surveillance  
•

Surveillance for notifiable Aedes-borne viral diseases and reporting of imported and autochthonous cases at
national and EU level (necessary);
SoHO: generic haemovigilance and biovigilance systems (necessary).

Laboratory diagnosis 
•

Provide professional guidelines for laboratory testing and clinical management of Aedes-borne viral diseases.

The production of guidelines for laboratory testing and clinical management of Aedes-borne viral infections requires 
the formation of an expert committee, possibly interdisciplinary (virologists, laboratory scientists, clinical specialists 
of infectious diseases, and public health experts) who, based on literature reviews and diagnostic and clinical data, 
identify effective diagnostic methods and management/treatment protocols. The laboratory testing guidelines 
should address protocols for sample collection, handling, and storage and recommend appropriate diagnostic 
assays based on performance metrics, such as sensitivity and specificity. The implementation of guidelines should 
include offering support and consultation to laboratories and clinicians and regular updates of the guidelines based 
on new evidence and technological advancements. 
•

Ensure there are laboratory capabilities within the country for diagnosis.

Key components of laboratory capabilities are: (i) range of diagnostic methods, including molecular methods, next-
generation sequencing, serological testing including neutralisation tests, and viral isolation and culture; (ii) number 
of target pathogens included in diagnostic tests; (iii) availability of advanced techniques (e.g. viral genome 
sequencing and analysis to track viral mutations and phylogenetic relationships, use of metagenomic approaches to 
identify novel or co-circulating pathogens in samples); (iv) expertise in bioinformatics for data analysis and 
interpretation; (v) research and development sector conducting studies to understand pathogen biology and to 
develop/update diagnostics tests; (vi) quality assurance and control − i.e. adherence to/development of 
international standards and guidelines (WHO, ECDC) and participation in/organisation of proficiency testing; (vii) 
collaboration with public health authorities, academic institutions and international organisations to share data, 
resources, and expertise; (viii) training and capacity building − i.e. providing training and support to other 
laboratories and public health entities to enhance overall diagnostic capabilities. 
•
•

Ensure that laboratory capacity is sufficient to diagnose imported and potential locally acquired cases.
Monitor the efficacy of laboratory diagnostic methods.

The efficacy of laboratory diagnostic methods can be monitored through the following activities: (i) participation in 
EQA programmes and inter-laboratory comparisons; (ii) adherence to quality control procedures (use of internal 
controls, routine check and validation of reagents and calibration and maintenance of equipment; (iii) validation 
and verification of new methods before implementation; (iv) monitoring and analysis of test results; (v) correlation 
of test results with clinical data and retesting of samples that produce unexpected or critical results; (vi) obtaining 
and maintaining certifications and accreditations from relevant authorities to ensure adherence to best practices. 
•

Ensure that access to laboratory testing is available for patients (including financial aspects of testing costs).

Awareness raising and capacity building 
•

•

Promote awareness among healthcare professionals of Aedes-borne viral diseases so that this will be 
considered in the differential diagnosis of travellers returning from affected areas.
Educate travellers to affected areas on how to reduce the risk (e.g. protect against infection during travel, 
consider pre-travel-vaccination in accordance with national guidelines).

Multi-sectoral collaboration and coordination 
•

Competent SoHO authorities should consider measures to prevent transmission to SoHO recipients through
transfusion or transplantation from donors returning from affected areas.

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Measures for blood, tissues, cells and organ safety could include the implementation of policies for the deferral or 
testing for Aedes-borne viruses of donors who have travelled to or resided in Aedes-borne virus affected areas and 
also the possible use of SoHO pathogen inactivation methods, where applicable. 

• 

Consult with the National Immunisation Technical Advisory Groups (NITAGs) and/or other competent body 
to define vaccination recommendations for residents and/or travellers to affected areas. 

In addition to personal protective measures, vaccination is a supplementary means of protecting against disease. 
As of 2025, two vaccines were available against dengue (Dengvaxia® and Qdenga®) and two against chikungunya 
virus (Ixchiq® and Vimkunya®), having received marketing authorisation from the European Medicines Agency 
(EMA) for use in the EU. There is no vaccine against Zika virus disease available in the EU/EEA. Vaccines should be 
used in accordance with manufactures’ instructions, based on the recommendations from NITAGs or other 
competent bodies (e.g. travel medicine vaccines). Vaccine recommendations will address priority target groups for 
vaccination, vaccination schedule, vaccine co-administrations, programmatic consideration for the deployment of 
the vaccine and risk communication. A strategy for post marketing studies should be clearly defined. 

Vector management (entomological surveillance and control activities) 
• 
• 

Develop a surveillance/monitoring plan for invasive Aedes mosquitoes in the area. 
Monitor the introduction of new invasive Aedes mosquitoes at points of entry. 

Early detection of new invasive mosquitoes increases the opportunity for appropriate and timely response 
measures and Aedes-borne disease prevention. For this purpose, a surveillance network must be set up to allow 
the early detection of an introduction/initial spread of invasive Aedes species before it establishes permanent 
populations and spreads over a wide area. The network should optimise resources by intelligently targeting the 
surveillance operations at as many previously defined high-risk sites as possible and at points of entry. Such points 
of entry could be storage sites for imported used tyres, shelters/greenhouses for imported plants, such as 
Dracaena spp. (Lucky Bamboo), large parking lots at country borders, highways and road axes that originate in 
colonised areas, ports, airports and railway stations. 

• 

Stimulate active and passive monitoring of vectors (e.g. reporting by citizens) 

While active monitoring mostly involves the trapping and reporting of mosquitoes by governmental, academic or 
commercially-run organisations, passive monitoring of vectors could consist of informing the general public (and/or 
children at schools) and requesting feedback from them (e.g. through mobile-phone-based reporting systems 
and/or by asking them to send in collected mosquito specimens for identification). 

• 

Model ecological niche suitability of the area for Ae. albopictus and Ae. aegypti 

While observations on the presence and absence of mosquitoes are essential to gain insight into the distribution 
and spread of invasive Aedes mosquitoes, it is not economically feasible to monitor each location. Ecological niche 
modelling provides estimates of the distribution status for those areas with no information currently available, by 
establishing statistical relationships between vector distribution data and predictor covariates. This technique could 
also help to make estimates of future ecological suitability in a changing climate. 

• 

Develop and apply vector control at points of entry, possibly including disinfection protocols on vessels and 
aircrafts arriving from areas where invasive Aedes mosquitoes are present, to mitigate the risk of 
introducing new vectors.  

Control measures include the use of larvicides in stagnant water, community education programmes, and the 
implementation of disinfection protocols at ports and airports. At points of entry, vector surveillance and control 
measures should aim to prevent the introduction of invasive Aedes mosquitoes by intercepting them before or on 
arrival. This may include implementing inspection and disinfection protocols on vessels and aircraft arriving from 
countries where these vectors are known to have already been established. In addition, the implementation of 
specific measures for high-risk goods coming from these countries could be considered: e.g. the prevention of 
water collection by covering used tyres or storing them indoors, and use of residual adulticidal applications if water 
is detected. For plants transported with water, such as lucky bamboo, consider applying larvicidal treatments to the 
water surrounding the plants and conduct mosquito surveillance both inside and outside greenhouses. 

• 

Identify and deploy appropriate vector control interventions after detecting the introduction of new vector 
species in order to prevent their establishment. 

Rapid and targeted action is essential to prevent the spread of invasive mosquitoes and reduce the risk of their 
establishment. By implementing effective control measures immediately, the potential for these vectors to establish 
and proliferate in new areas can be minimised, safeguarding public health. 

Links to further information on surveillance, preparedness and response (control) actions are provided in Annex 1. 

12 

 
 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Risk level 2 - Predisposed area 

Risk level 2a - Predisposed area with low receptivity 

Description and triggers for re-assessment 
• 
• 

Ae. albopictus or/and Ae. aegypti are established in the area. 
The vector density is generally low (as described in ECDC’s technical report ‘Guidelines for the surveillance 
of invasive mosquitoes in Europe’ [36]. 
The climatic conditions are generally unfavourable for Aedes-borne virus transmission. 
Public health actions focus on surveillance of imported cases and mosquito vectors, prevention and 
preparedness. 
Re-assessment triggers: 
− 

weather conditions becoming favourable for Aedes-borne virus transmission (based on 
meteorological data and potentially modelling). → Move to Risk Level 2b; 
vector densities becoming higher (based on mosquito surveillance data). → Move to Risk Level 2b; 
detection of the first autochthonous case(s) of an Aedes-borne viral disease. → Move to Risk Level 3a. 

− 
− 

• 
• 

• 

Public health actions and interventions 
(Activities in italics have been specified at lower level(s) and are also relevant at this risk level.) 

Disease surveillance  
• 

Surveillance for notifiable Aedes-borne viral diseases and reporting of imported and autochthonous cases at 
national and EU level (necessary). 
SoHO: generic haemovigilance and biovigilance systems (necessary). 

• 

Laboratory diagnosis 
• 

Ensure that laboratory capacity is sufficient (including stock of tests in the event of a surge in demand). 

Key aspects to be considered are (i) use of high-throughput automated systems to increase the volume of testing; 
(ii) availability of resources (i.e. diagnostic equipment such as PCR machines, ELISA readers, sequencers and 
adequate stock of necessary reagents, kits, and other consumables); (iii) staff availability − i.e. sufficient number 
of trained laboratory personnel to perform tests and manage data and ongoing training programmes to keep staff 
updated on new testing protocols and emerging viruses; (iv) adequate infrastructure − i.e. sufficient laboratory 
space to handle increased sample volume during outbreaks and appropriate biosafety levels (BSL-2 to BSL-4); (v) 
operational capacity − i.e. ability to extend operating hours or work multiple shifts during outbreak situations and 
systems in place for rapid scale-up of testing capacity in response to outbreaks; (vi) logistical support − i.e. 
efficient management of supply chains to ensure continuous availability of necessary materials and robust data 
management systems to handle large volumes of test results and epidemiological data. 
• 
• 
• 
• 

Provide professional guidelines for laboratory testing and clinical management of Aedes-borne viral diseases. 
Ensure there are laboratory capabilities within the country for diagnosis. 
Monitor the efficacy of laboratory diagnostic methods. 
Ensure that access to laboratory testing is available for patients (including financial aspects of testing). 

Awareness raising and capacity building 
• 

Implement training courses (e.g. on testing, diagnosis, prevention and case management), information and 
management recommendations. 
Educate travellers coming from affected areas on how to reduce the risk of further transmission (e.g. 
protect against mosquito bites in accordance with national guidelines). 
Conduct public information campaigns on Aedes-borne diseases (e.g. on the need to consult a healthcare 
professional in the event of symptoms) and on the use of personal protective measures against mosquito 
bites and source reduction. 
Promote awareness amongst healthcare professionals of Aedes-borne viral diseases so that this will be 
considered in the differential diagnosis of travellers returning from affected areas. 
Educate travellers to affected areas on how to reduce the risk (e.g. protect against infection during travel, 
consider pre-travel-vaccination in accordance with national guidelines). 
Educate travellers coming from affected areas on how to reduce the risk of further transmission (e.g. 
protect against mosquito bites in accordance with national guidelines). 

Multi-sectoral collaboration and coordination 
• 

Define response and control measures for imported cases of Aedes-borne viral diseases (e.g. vector control 
at the residence of an imported case during the season). 
Consider drafting a preparedness and response plan for autochthonous transmission of Aedes-borne viral 
diseases. 

• 

• 

• 

• 

• 

• 

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ECDC GUIDANCE 

The preparedness and response plan could be based on the risk levels presented in this document and should 
delineate roles and responsibilities for activities such as outbreak investigation, surveillance, vector control, risk 
communication and community engagement, and SoHO safety. Preparedness and response plans are ideally 
reviewed and revised based upon the lessons learned from past outbreaks. 

• 

• 

• 

Establish a multi-sectoral coordination committee (national or regional) for exchange of information 
between affected sectors (e.g. public health, SoHO safety, integrated landscape management, medical 
entomology and vector control), as part of the preparedness plan. 
Consult with competent authorities for SoHO to consider measures to prevent transmission to SoHO 
recipients through transfusion or transplantation from donors returning from affected areas. 
Consult with the NITAGs and/or other competent bodies to define vaccination recommendations for 
residents and/or travellers to affected areas.  

Vector management (entomological surveillance and control activities) 
• 

Develop a surveillance/monitoring plan for Aedes mosquito presence and abundance in the area 
(necessary). 
Monitor the densities of invasive Aedes mosquitoes in the risk area. 

• 

In areas where invasive Aedes mosquito species have become established, surveillance of their abundance and 
further spread is needed for timely risk assessment of pathogen transmission to humans. Where the vector density 
is generally low, and where the climatic conditions are generally unfavourable for Aedes-borne virus transmission, it 
would be most economical to focus on mosquito abundance/density measurements during the month(s) where the 
seasonal density may be expected to be at or near its maximum (density typically peaks during the summer 
months, but it can be bi-modal in areas with hot and dry summers). 

• 
• 

Model disease transmission potential (basic reproduction number) by Ae. albopictus and/or Ae. aegypti. 
Identify and apply appropriate vector control interventions to mitigate geographical spread and density 
increase of vectors. 

Implementing targeted strategies, such as treatment with registered biocides, environmental management and 
community education to remove stagnant water bodies, can effectively reduce the density of vectors. Active 
community involvement is crucial. Encourage citizens to report mosquitoes and participate in local vector control 
activities. Monitoring and adapting these interventions based on local conditions and vector behaviour are critical 
for controlling the spread and maintaining low vector densities, thereby protecting public health. 

• 

• 
• 
• 
• 

• 

Promote awareness among the general population and local authorities of how to control mosquito breeding 
sites. 
Monitor the introduction of new invasive Aedes mosquitoes at points of entry. 
Stimulate active and passive monitoring of vectors (e.g. reporting by citizens). 
Model ecological niche suitability of the area for Ae. albopictus and Ae. aegypti. 
Develop and apply vector control at points of entry, possibly including disinfection protocols on vessels and 
aircrafts arriving from areas where invasive Aedes mosquitoes are present, to mitigate the risk of 
introducing new vectors. 
Identify and deploy appropriate vector control interventions after new vector species introductions have 
been detected to prevent their establishment. 

Links to further information on surveillance, preparedness and response (control) actions are provided in Annex 1. 

14 

 
 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Risk Level 2b - Predisposed area with high receptivity and vulnerability 

Description and triggers for re-assessment 
• 
• 

Vectors of Aedes-borne viruses are established and widespread. 
Vector densities are generally high, according to criteria described in ECDC’s ‘Guidelines for the surveillance 
of invasive mosquitoes in Europe’ [36]. 
The environmental and climatic conditions are favourable for autochthonous transmission of Aedes-borne viral diseases. 
High number of travellers from Level 3 and Level 4 areas. 
Public health actions focus on surveillance of imported cases, possible autochthonous cases and mosquito 
vectors, and prevention and preparedness. 
Re-assessment triggers: 
− 

Environmental conditions becoming unfavourable for Aedes-borne virus transmission (based on 
meteorological data and potentially modelling). → Move to Risk Level 2a. 
Aedes vector densities becoming low (based on mosquito monitoring data). → Move to Risk Level 2a. 
Number of travellers from Level 3 and Level 4 areas becoming low. → Move to Risk Level 2a. 
Detection of the first autochthonous case of Aedes-borne viral disease. → Move to Risk Level 3a. 

− 
− 
− 

Public health actions and interventions 
(Activities in italics have been specified at lower level(s) and are also relevant at this risk level). 

Disease surveillance  
• 

Surveillance for notifiable Aedes-borne viral diseases and reporting of imported and autochthonous cases at 
national and EU level (necessary). 
SoHO: generic haemovigilance and biovigilance systems (necessary). 

Laboratory diagnosis 
• 
• 
• 
• 
• 

Provide professional guidelines for laboratory testing and clinical management of Aedes-borne viral diseases. 
Ensure there are laboratory capabilities within the country for diagnosis. 
Ensure that laboratory capacity is sufficient (including stock of tests in the event of a surge in demand). 
Monitor the efficacy of laboratory diagnostic methods. 
Ensure that access to laboratory testing is available for patients (including financial aspects of testing). 

Awareness raising and capacity building  
• 

Advise infected patients (imported cases) and asymptomatic travellers coming from affected countries/Level 
3-4 areas to take measures to prevent onward transmission. 
Intensify public information campaigns on Aedes-borne diseases (e.g. the need to consult a healthcare 
professional in the event of symptoms) and to reinforce the use of personal protective measures against 
mosquito bites and source reduction/larval control of mosquitoes. 
Intensify awareness among healthcare professionals of Aedes-borne viral diseases for differential diagnosis 
of travellers coming from affected areas, and for locally acquired cases (especially in areas where there 
have been autochthonous transmissions in the past). 
Implement training courses (e.g. testing, diagnosis, prevention and case management), information and 
management recommendations. 
Conduct public information campaigns on Aedes-borne diseases (e.g. on the need to consult a healthcare 
professional in the event of symptoms) and on the use of personal protective measures against mosquito 
bites and source reduction of mosquitoes. 
Promote awareness among healthcare professionals of Aedes-borne viral diseases so that this will be 
considered in the differential diagnosis of travellers coming or returning from affected areas. 
Educate travellers to affected areas on how to reduce risk (e.g. protect against infection during travel, 
consider pre-travel-vaccination in accordance with national guidelines). 
Educate travellers coming from affected areas on how to reduce the risk of further transmission (e.g. 
protect against mosquito bites in accordance with national guidelines). 

Multi-sectoral collaboration and coordination 
• 

Develop a preparedness and response plan for autochthonous Aedes-borne virus transmissions, including 
surveillance activities (e.g. active case finding, population screening, enhanced mosquito monitoring) and 
an integrated vector control plan. 
Allocate resources necessary to enable emergency response (i.e. vector control, communication plan). 
Ensure timely and regular exchange of information between affected sectors through the multi-sectoral 
coordination committee, as part of the preparedness plan. 
Community mobilisation, involvement of a broad range of stakeholders. 
Consult with the NITAGs and/or other competent body to define vaccination recommendations for residents 
and/or travellers to affected areas. 

• 
• 
• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 
• 

• 
• 

15 

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ECDC GUIDANCE 

• 

• 

Define response and control measures for imported cases of Aedes-borne viral diseases (e.g. active case 
finding and vector control at the residence of an imported case during the season). 
Consult with competent authorities for SoHO to consider measures to prevent transmission to SoHO 
recipients through transfusion or transplantation from donors returning from affected areas. 

Vector management (entomological surveillance and control 
activities) 
• 

Monitor the densities and seasonal dynamics of invasive Aedes mosquitoes in the risk area (necessary). 

If invasive Aedes mosquito species are established over wide areas (risk Level 2b and above) they should be 
surveyed to assess the abundance/density of the population and its seasonal dynamics (throughout the year). 
These data, together with other mosquito population parameters (e.g. host preferences), will help to evaluate the 
vectorial capacity of the mosquito population in the local context. 

• 

Based on the preparedness and control plan: consider preparing Aedes vector control activities if 
entomological indicators suggest there is a need. 

Key indicators to monitor include Aedes adult female mosquito density, egg abundance (measured in ovitraps), 
larval and pupal indices and the risk of arbovirus transmission in the area. Evaluation of these indicators is crucial 
when implementing targeted control measures to prevent the spread of Aedes-borne viral diseases. 

• 

Based on the preparedness and control plan: implement larval vector control activities when and where 
appropriate (e.g. drainage catch basins). 

Implementing larval vector control activities, such as targeting drainage catch basins, at appropriate periods and 
locations is crucial for reducing vector populations. This proactive approach helps to disrupt the mosquito life cycle 
effectively, reducing the emergence of adult mosquitoes and minimising the risk of Aedes-borne disease transmission to 
the targeted area. It is noted that larval control − i.e. environmental management, source reduction, larviciding, or 
biological control (community-based and/or top- down approaches) can be conducted when cases are detected, but is 
more effective when it is consistent and routine rather than as a periodic emergency response. 

• 

Based on the preparedness and control plan: consider implementing ground adult vector control activities around 
imported confirmed or probable cases, and probable local cases where epidemiological evidence suggests there is 
a strong likelihood of Aedes-borne disease, during the active vector season. 

Rapid action in the proximity of reported cases helps to prevent further transmission and protects the community 
from outbreaks of Aedes-borne diseases. Adulticidal products mainly fall within the category of pyrethroids, which 
are not recommended for use on a large scale. In the case of virus transmission, ‘peri- domestic’ or ‘perifocal’ 
space spray treatments with insecticides can be carried out in and around households where human infection is 
suspected or has been reported. Different treatment methods (house-to-house application using portable 
equipment, vehicle-mounted fogging, and cold or thermal fogging) are available, but they must be tailored to the 
risk scenario, the area to be covered, accessibility and the Aedes species. 

• 

Monitor the efficacy of control activities against the target mosquito populations, including insecticide 
resistance, if appropriate. 

Regular monitoring of the effectiveness of control activities against target mosquito vectors, including the assessment of 
insecticide resistance where applicable, is critical. This ongoing evaluation ensures that interventions remain efficient. In the 
case of long-term control programmes, rotation of available insecticides should be adopted, as resistance has already been 
detected in some European populations following insecticide-based mosquito management programmes. Adulticide products 
mainly fall within the category of pyrethroids which, in the case of Ae. albopictus controls, are only recommended in specific 
cases (e.g. imported cases) and not as a method for use on a large scale. 

• 
• 
• 

• 
• 

• 

Monitor the introduction of new invasive Aedes mosquitoes at points of entry. 
Model disease transmission potential (basic reproduction number) by Ae. albopictus and Ae. aegypti. 
Identify and apply appropriate vector control interventions to mitigate geographic spread and density 
increase of vectors. 
Promote awareness among the general population and local authorities of the need to control mosquito breeding sites. 
Develop and apply vector control at points of entry, possibly including disinfection protocols on vessels and 
aircrafts arriving from areas where invasive Aedes mosquitoes are present, to mitigate the risk of 
introducing new vectors. 
Identify and deploy appropriate vector control interventions after detecting the introduction of new vector 
species to prevent their establishment. 

Links to further information on surveillance, preparedness and response (control) actions are provided in Annex 1. 

16 

 
 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Risk level 3 - Affected area 

Risk level 3a – Affected area with low number of cases 

Description and triggers for re-assessment 
• 

At least one autochthonous case detected (i.e. confirmed case according to EU case definition [37], or, if 
not applicable, according to national case definition). 
The number of autochthonous cases/clusters is low and transmission chains are traceable. 
Public health actions and interventions focus on surveillance, prevention, response and control. 
Re-assessment triggers: 
− 

45 days passed since the date of onset of the last autochthonous case. (the 45-day period is 
calculated as the sum of the days after symptom onset until viraemia levels are sufficient to infect a 
mosquito (four days), the longevity of an Aedes mosquito in natural circumstances (23 days) and the 
maximum intrinsic incubation period (14 days), with a four-day safety margin for clinical diagnosis of 
new cases.) → Move to Risk Level 2a or 2b. 
The number of autochthonous cases and clusters becoming high, which is overwhelming tracing 
capacity. → Move to Risk Level 3b. 

− 

Public health actions and interventions 

(Activities in italics have been specified at lower level(s) and are also relevant at this risk level.) 

Disease surveillance activities 
• 

Active case finding in the area with confirmed autochthonous transmission (necessary). Ensure timely detection 
and reporting of imported or autochthonous cases at local, regional and national level (necessary). 
Ensure timely reporting of autochthonous cases at EU level (necessary). 
Apply molecular surveillance/genotyping/serotyping of viruses (necessary). 
Reporting of surveillance data of asymptomatic infections through active case finding and blood donation 
screening (if applicable and if testing of donations for the relevant virus is implemented in the area as a 
SoHO safety measure) (necessary). 
Track transmission chains to define the affected areas and transmission dynamics. 
Surveillance for notifiable Aedes-borne viral diseases and reporting of imported and autochthonous cases at 
national and EU level (necessary). 
SoHO: generic haemovigilance and biovigilance systems (necessary). 

Laboratory diagnosis 
• 
• 
• 
• 
• 

Provide professional guidelines for laboratory testing and clinical management of Aedes-borne viral diseases. 
Ensure there are laboratory capabilities within the country for diagnosis. 
Ensure that laboratory capacity is sufficient (including stock of tests in the event of a surge in demand). 
Monitor the efficacy of laboratory diagnostic methods. 
Ensure that access to laboratory testing is available for patients (including financial aspects of testing). 

Awareness raising and capacity building 
• 

Increase awareness among health professionals for the diagnosis of locally-acquired cases too (diagnostic 
strategy; case management; reporting, prevention recommendations). 
Advise infected patients and asymptomatic travellers coming from affected countries/Level 3-4 areas to take 
measures to prevent onward transmission. 
Intensify public information campaigns on Aedes-borne diseases (e.g. the need to consult a healthcare 
professional in case of symptoms) and to strengthen the use of personal protective measures against 
mosquito bites and source reduction/larval control of mosquitoes. 
Implement training courses (e.g. on testing, diagnosis, prevention and case management), information and 
management recommendations. 
Conduct public information campaigns on Aedes-borne diseases (e.g. the need to consult a healthcare 
professional in case of symptoms) and on the use of personal protective measures against mosquito bites 
and source reduction. 
Educate travellers to affected areas on how to reduce the risk (e.g. protect against infection during travel, 
consider pre-travel-vaccination in accordance with national guidelines). 
Educate travellers coming from affected areas on how to reduce the risk of further transmission (e.g. 
protect against mosquito bites in accordance with national guidelines). 

• 
• 
• 

• 
• 
• 

• 
• 

• 

• 

• 

• 

• 

• 

• 

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ECDC GUIDANCE 

Multi-sectoral collaboration and coordination 
• 

• 

• 

• 

Apply response and control measures in the event of confirmed autochthonous and imported cases of 
Aedes-borne viral diseases. 
Based on consultation with the multi-sectoral coordination committee, and according to the preparedness 
and response plan, establish a multi-sectoral outbreak emergency response team and organise regular 
meetings. 
Determine the geographical boundaries for implementation of various response measures in and around the 
affected area.  
Safety of SoHO: consider implementing measures for blood, tissues, cells and organ safety in affected area, 
based on risk assessment. 

The measures could be based on a risk assessment for donor-derived transmission through SoHO. The measures 
implemented could consider the supply of SoHO in the affected area. Measures may include temporary suspension 
of SoHO collection or screening of donors with nucleic acid amplification testing (NAAT) in the affected area, 
implementing deferral policies or NAAT screening of donors who travelled or stayed in the area, pathogen 
inactivation methods for certain SoHO components/grafts, and evaluating the impact of these measures on SoHO 
supplies. The specific measures may vary depending on the size of the affected area and the available supply; for 
example, suspension of collection in a large area may significantly affect supply. In such cases, testing of donors 
may be a more appropriate alternative. 

• 
• 

Review and - if necessary - modify/refine the preparedness and response plan. 
Perform in-action and after-action reviews, identify the reasons for ineffective response actions, if applicable. 

In-action reviews can be conducted quickly during ongoing outbreaks to ensure that the response is running 
optimally. Following the conclusion of outbreaks, after-action reviews offer the opportunity for structured learning 
from the event, so that lessons may be learned and incorporated into future response activities. 

• 

• 

• 

• 

• 
• 

• 

Consult with competent authorities for SoHO to consider measures to prevent transmission to SoHO 
recipients through transfusion or transplantation from donors returning from affected areas. 
Consult with the NITAGs and/or other competent body to define vaccination recommendations for residents 
and/or travellers to affected areas. 
Develop a preparedness and response plan for autochthonous Aedes-borne virus transmissions, including 
surveillance activities and an integrated vector control plan. 
Define response and control measures for imported cases of Aedes-borne viral diseases (e.g. active case 
finding and/or vector control at the residence of an imported case during the season). 
Allocate the resources necessary to enable emergency response (i.e. vector control, communication plan). 
Ensure timely and regular exchange of information between affected sectors through the multi-sectoral 
coordination committee, as part of the preparedness plan. 
Community mobilisation, involvement of a broad range of stakeholders. 

Vector management (entomological surveillance and control activities) 
• 
• 
• 
• 
• 

Implement ground adult vector control activities around cases of Aedes-borne disease. 
Monitor the densities and seasonal dynamics of invasive Aedes mosquitoes in the risk area (necessary). 
Monitor the introduction of new invasive Aedes mosquitoes at points of entry. 
Model disease transmission potential (basic reproduction number) by Ae. albopictus and Ae. aegypti. 
Based on the preparedness and control plan: consider preparing Aedes vector control activities if 
entomological indicators suggest there is a need to do so. 
Based on the preparedness and control plan: implement larval vector control activities when and where 
appropriate (e.g. drainage catch basins). 
Based on the preparedness and control plan: consider implementing ground adult vector control activities 
around imported confirmed or probable cases, and probable local cases where epidemiological evidence 
suggests high likelihood of Aedes-borne disease, during the active vector season. 
Monitor the efficacy of control activities against the target mosquito populations, including insecticide 
resistance, if appropriate. 
Promote awareness among the general population and local authorities about controlling mosquitoes 
breeding sites. 
Develop and apply vector control at points of entry, possibly including disinfection protocols on vessels and 
aircrafts arriving from areas where invasive Aedes mosquitoes are present, to mitigate the risk of 
introducing new vectors. 
Identify and deploy appropriate vector control interventions after detecting new vector species introductions 
to prevent their establishment. 

• 

• 

• 

• 

• 

• 

Links to further information on surveillance, preparedness and response (control) actions are provided in Annex 1. 

18 

 
 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Risk level 3b – Affected area with high number of cases 

Description and triggers for re-assessment 
• 

The number of autochthonous cases/clusters is high, which is overwhelming tracing capacity and targeted 
vector control interventions. 
Public health actions and interventions are focusing on response and control. 
Re-assessment triggers: 
− 
− 
− 

The number of autochthonous cases and clusters are decreasing. → Move to Risk Level 3a. 
Sufficient capacities for the tracing of transmission chains. → Move to Risk Level 3a. 
Autochthonous transmissions have occurred throughout the year, without importation of new 
viruses. → Move to Risk Level 4. 

Public health actions and interventions 

(Activities in italics have been specified at lower level(s) and are also relevant at this risk level). 

Disease surveillance  
• 
• 
• 
• 
• 

Active case finding in the area with autochthonous transmission if applicable. 
Ensure timely detection and reporting of imported or autochthonous cases at local, regional and national level. 
Ensure timely reporting of autochthonous cases at EU level (necessary). 
Apply molecular surveillance/genotyping/serotyping of viruses (necessary). 
Reporting of surveillance data for asymptomatic infections through active case finding and blood donation 
screening (if applicable and if donations are tested for the relevant virus in the area as a SoHO safety 
measure) (necessary). 
Surveillance for notifiable Aedes-borne viral diseases and reporting of imported and autochthonous cases at 
national and EU level (necessary). 
SoHO: generic haemovigilance and biovigilance systems (necessary). 

Laboratory diagnosis 
• 
• 
• 
• 
• 

Provide professional guidelines for laboratory testing and clinical management of Aedes-borne viral diseases. 
Ensure there are laboratory capabilities within the country for diagnosis. 
Ensure that laboratory capacity is sufficient (including stock of tests in the event of a surge in demand). 
Monitor the efficacy of laboratory diagnostic methods. 
Ensure that access to laboratory testing is available for patients (including financial aspects of testing). 

Awareness raising and capacity building 
• 

Increase awareness among health professionals for the diagnosis of locally-acquired cases too (diagnostic 
strategy; case management; reporting, prevention recommendations). 
Advise infected patients and asymptomatic travellers coming from affected countries/Level 3-4 areas to take 
measures to prevent onward transmission. 
Intensify public information campaigns on Aedes-borne diseases (e.g. the need to consult a healthcare 
professional in case of symptoms) and to strengthen the use of personal protective measures against 
mosquito bites and source reduction/larval control of mosquitoes. 
Conduct public information campaigns on Aedes-borne diseases (e.g. the need to consult a healthcare 
professional in case of symptoms) and on the use of personal protective measures against mosquito bites 
and source reduction. 

Multi-sectoral collaboration and coordination 
• 

Review the response and control strategies and, depending on the resources available and cost-
effectiveness, consider modifying the preparedness and response plan (e.g. prioritise places to treat; treat 
whole neighbourhoods). 
Implement the modified preparedness and response plan. 
Apply modifications in the response and control measures for autochthonous and imported cases of Aedes-
borne viral diseases. 
Safety of SoHO: consider implementing measures for blood, tissues, cells and organ safety in affected area, 
based on risk assessment. 
Consult with competent authorities for SoHO to consider measures to prevent transmission to SoHO 
recipients through transfusion or transplantation from donors returning from affected areas. 
Consult with the NITAGs and/or other competent body to define vaccination recommendations for residents 
and/or travellers to affected areas. 
Based on consultation with the multi-sectoral coordination committee, and according to the preparedness and 
response plan, establish a multi-sectoral outbreak emergency response team and organise regular meetings. 

• 
• 

• 

• 

• 

• 

• 

• 
• 

• 

• 

• 

• 

19 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

ECDC GUIDANCE 

• 

• 
• 
• 

Determine the geographical boundaries for implementation of various response measures in and around the 
affected area. 
Perform in-action and after-action reviews, identify the reasons for ineffective response actions, if applicable. 
Allocate the resources necessary to enable emergency response (i.e. vector control, communication plan). 
Ensure timely and regular exchange of information between affected sectors through the multi-sectoral 
coordination committee, as part of the preparedness plan. 

Vector management (entomological surveillance and control 
activities) 
• 

Intensify ground adult mosquito control (space spraying or residual spraying) with multiple applications in 
areas of active transmission. 

Intensifying ground adult mosquito control through methods such as space or residual spraying with multiple 
applications is essential in high-risk areas with an increased number of locally acquired cases. This approach not 
only quickly reduces the adult mosquito populations but also serves to prevent further transmission of Aedes-borne 
diseases in the targeted area. 

• 
• 
• 

• 

• 
• 

• 

Monitor the introduction of new invasive Aedes mosquitoes at points of entry. 
Model disease transmission potential (basic reproduction number) by Ae. albopictus and Ae. aegypti. 
Based on the preparedness and control plan: implement larval vector control activities when and where 
appropriate (e.g. drainage catch basins).  
Monitor the efficacy of control activities against target mosquito populations, including insecticide 
resistance, if appropriate.  
Promote awareness among the general population and local authorities on controlling mosquito breeding sites. 
Develop and apply vector control at points of entry, possibly including disinfection protocols on vessels and 
aircrafts arriving from areas where invasive Aedes mosquitoes are present, to mitigate the risk of 
introducing new vectors.  
Identify and deploy appropriate vector control interventions after detecting new vector species introductions 
to prevent their establishment. 

Links to further information on surveillance, preparedness and response (control) actions are provided in Annex 1. 

20 

 
 
 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Risk level 4 - Endemo-epidemic area 

Description and triggers for re-assessment 
• 

Autochthonous transmission of Aedes-borne viral diseases in subsequent years, independent from the 
importation of new viruses. 
Aedes-borne viruses are frequently introduced and result in further, autochthonous transmissions and outbreaks. 
Public health actions and interventions are focusing on surveillance, response and control. 

Public health actions and interventions 

(Activities in italics have been specified at lower level(s) and are also relevant at this risk level.) 

Disease surveillance activities 
• 

Apply targeted surveillance (e.g. testing patients with fever) at the beginning of the seasonal enhanced 
circulation for the timely detection of outbreaks. 
Ensure timely detection and reporting of imported or autochthonous cases at local, regional and national level. 
Ensure timely reporting of autochthonous cases at EU level (necessary). 
Apply molecular surveillance/genotyping/serotyping of viruses (necessary). 
Reporting of surveillance data on asymptomatic infections through active case finding and blood donation 
screening (if applicable and if donations are tested for the relevant virus in the area as a SoHO safety 
measure) (necessary). 
Surveillance for notifiable Aedes-borne viral diseases and reporting of imported and autochthonous cases at 
national and EU level (necessary). 
SoHO: generic haemovigilance and biovigilance systems (necessary). 

Laboratory diagnosis 
• 
• 
• 
• 
• 

Provide professional guidelines for laboratory testing and clinical management of Aedes-borne viral diseases. 
Ensure there are laboratory capabilities within the country for diagnosis. 
Ensure that laboratory capacity is sufficient (including stock of tests in the event of a surge in demand). 
Monitor the efficacy of laboratory diagnostic methods. 
Ensure that access to laboratory testing is available for patients (including financial aspects of testing). 

Awareness raising and capacity building 
• 

Organise regular public information campaigns and improve education on Aedes-borne diseases to 
strengthen use of personal protective measures against mosquito bites and source reduction/continued 
larval control of mosquitoes. 
Increase awareness among health professionals at the beginning of the high intensity transmission season 
every year. 
Conduct/intensify public information campaigns on Aedes-borne diseases (e.g. the need to consult a healthcare 
professional in case of symptoms) and on the use of personal protective measures against mosquito bites and 
source reduction at the beginning of the high intensity transmission season every year. 
Increase awareness among health professionals for the diagnosis of locally-acquired cases too (diagnostic 
strategy; case management; reporting, prevention recommendations). 
Advise infected patients and asymptomatic travellers coming from affected countries/Level 3-4 areas to take 
measures to prevent onward transmission. 
Intensify public information campaigns on Aedes-borne diseases (e.g. the need to consult a healthcare 
professional in case of symptoms) and to strengthen the use of personal protective measures against 
mosquito bites and source reduction/larval control of mosquitoes. 

Multi-sectoral collaboration and coordination 
• 

Consult with the NITAGs and/or other competent body to define vaccination recommendations for residents 
and/or travellers to affected areas. 
Safety of SoHO: consider implementing measures for blood, tissues, cells and organ safety in affected area, 
based on risk assessment. 
Review the response and control strategies and, depending on the available resources and cost-
effectiveness, consider modifying the preparedness and response plan (e.g. prioritise places to treat; treat 
whole neighbourhoods). 
Implement the modified preparedness and response plan. 
Based on consultation with the multi-sectoral coordination committee, and according to the preparedness and 
response plan, establish a multi-sectoral outbreak emergency response team and organise regular meetings. 
Determine the geographical boundaries for implementation of response measures in and around the affected area. 
Perform in-action and after-action reviews, identify the reasons for ineffective response actions, if applicable. 
Allocate resources necessary to enable emergency response (i.e. vector control, communication plan). 

• 
• 

• 
• 
• 
• 

• 

• 

• 

• 

• 

• 

• 

• 

• 

• 
• 

• 
• 
• 

21 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

ECDC GUIDANCE 

• 

• 

Ensure timely and regular exchange of information between affected sectors through the multi-sectoral 
coordination committee, as part of the preparedness plan. 
Apply response and control measures in the event of autochthonous and imported cases of Aedes-borne 
viral diseases. 

Vector management (entomological surveillance and control activities) 
• 

Consider testing the presence of viruses in mosquitoes to determine minimum infection rates. 

The infection rates of mosquitoes are often very low, and therefore it makes sense to test pools of mosquitoes, 
rather than individual mosquitoes. When a pool tests positive, it is not possible to quantify if one or more 
mosquitoes in that pool was positive. Therefore, the minimum infection rate is calculated by the number of positive 
pools divided by the total number of mosquitoes tested (x 1000). Cost-effectiveness of the entomo-virological 
surveillance may be considered before implementation. 

• 
• 
• 
• 
• 

• 

• 

• 

• 

Monitor the densities and seasonal dynamics of invasive Aedes mosquitoes in the risk area. 
Monitor the introduction of new invasive Aedes mosquitoes at points of entry.  
Model disease transmission potential (basic reproduction number) by Ae. albopictus and Ae. aegypti. 
Implement ground adult vector control activities around cases of Aedes-borne disease. 
Based on the preparedness and control plan: implement larval vector control activities when and where 
appropriate (e.g. drainage catch basins). 
Monitor the efficacy of control activities against the target mosquito populations, including insecticide 
resistance, if appropriate.  
Promote awareness among the general population and local authorities of the need to control mosquito 
breeding sites. 
Develop and apply vector control at points of entry, possibly including disinfection protocols on vessels and 
aircrafts arriving from areas where invasive Aedes mosquitoes are present, to mitigate the risk of 
introducing new vectors.  
Identify and deploy appropriate vector control interventions after detecting new vector species introductions 
to prevent their establishment. 

Links to further information on surveillance, preparedness and response (control) actions are provided in Annex 1. 

22 

 
 
ECDC GUIDANCE 

Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Knowledge gaps and limitations  

Pathogen-host interactions 
In general, there is a lack of knowledge about the susceptibility of EU/EEA population to severe Aedes-borne virus 
infections: The immunological landscape of the EU/EEA population in relation to Aedes-borne viruses remains 
poorly characterised. Factors such as pre-existing flavivirus immunity, which may contribute to ADE or cross-
protection, need thorough investigation. In particular, the impact of simultaneous or sequential infections (or 
vaccination) with multiple orthoflaviviruses, or with other pathogens endemic to Europe, on disease severity and 
immune responses is not well understood. In addition, the impact of demographic shifts, particularly the ageing 
population and increasing prevalence of chronic diseases, on infection outcomes is not well understood. Genetic 
factors, such as polymorphisms in Fc receptors or cytokine genes, which may influence disease severity, require 
comprehensive study in the European context. There is also limited knowledge of the long-term sequelae of Aedes-
borne viral infections in European populations. The potential for chronic health effects, particularly neurological and 
autoimmune complications, following acute infections also needs further investigation in the context of European 
healthcare systems and population demographics. 

Diagnosis 
There is a need for improved diagnostic capabilities, including the development of multiplex assays for 
simultaneous detection of multiple Aedes-borne viruses and the validation of point-of-care diagnostics suitable for 
field use in Europe. 

Surveillance and response 
The disease surveillance systems in the EU/EEA are predominantly based on the detection of symptomatic cases. 
However, asymptomatic infections with certain Aedes-borne viruses (e.g. DENV, ZIKV) may reach 80% and asymptomatic 
viraemic individuals can also transmit the virus to mosquitoes. Active case finding during an outbreak or serosurveillance 
studies after an outbreak may give a more precise indication of the number of people infected. The entomological 
surveillance in many countries is limited or fragmented both spatially and temporally, which reduces the usefulness of the 
mosquito surveillance data for trend analysis, timely risk assessment and alerting. 

Detailed analysis of the locally acquired dengue and chikungunya virus disease outbreaks in the EU could identify 
the effectiveness and efficiency of the applied public health measures for outbreak mitigation, containment and 
elimination. 

Prevention and treatment 
The development of national vaccine recommendations is a competency of the NITAGs, albeit with some 
particularities with regard to the vaccine recommendations for travellers. Few countries have issued 
recommendations concerning dengue and chikungunya vaccines for the protection of travellers and/or outbreak 
management purposes. The effectiveness of Qdengua® vaccine against DENV-3 and DENV-4 serotypes in 
seronegative individuals still needs to be documented. Vaccines against chikungunya virus have received marketing 
authorisations based on immunogenicity study results and there is currently a lack of data on the 
efficacy/effectiveness of the vaccines. Deployment of the above vaccines as part of outbreak management should 
be closely monitored in terms of safety, effectiveness and vaccination coverage.  

The development of broad-spectrum antivirals targeting conserved viral proteins (e.g. NS3 or NS5) of Aedes-borne 
viruses is a research priority. The potential for repurposing existing drugs, such as nucleoside analogues or host-
targeting antivirals, requires exploration. In addition, combination therapies to mitigate the risk of antiviral 
resistance should be investigated. 

Vector ecology and vector management 
While Ae. albopictus is established in several parts of the EU and laboratory experiments indicate vectorial capacity 
for several arboviruses beyond DENV, CHIKV and ZIKV (e.g. YFV, Rift Valley fever virus), its ability to transmit these 
viruses under natural conditions in the EU remains unknown.  

The potential establishment of Ae. aegypti in mainland EU/EEA could significantly alter arbovirus transmission 
dynamics. Predictive modelling incorporating climate change scenarios, urbanisation patterns and human mobility 
is needed to assess the risk and potential impact. The competitive interactions between Ae. aegypti and 
established Ae. albopictus populations and their implications for virus transmission need investigation. 

23 

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ECDC GUIDANCE 

In addition, little is known about the vectorial capacity of local Aedes species native to Europe for various 
arboviruses. The potential for virus adaptation to new vector species and the impact on transmission dynamics 
require further investigation. Detailed entomological studies, including vector competence assays and field-based 
transmission studies, are needed. 

There is a sub-optimal understanding of the socio-economic drivers of Aedes-borne virus transmission in Europe. 
The role of factors such as urbanisation patterns, international trade and travel in facilitating vector spread and 
virus introduction needs more comprehensive analysis to inform policy decisions. The specific adaptations of Aedes 
mosquitoes to European urban environments, including their breeding preferences and dispersal patterns, are also 
not fully characterised. This knowledge is crucial for developing targeted control strategies and predicting 
transmission hotspots. The impact of climate change on vector competence and extrinsic incubation periods of 
Aedes-borne viruses in European Aedes populations should also be investigated, as well as the potential role of 
vertical transmission in over-wintering and maintenance of Aedes-borne viruses in temperate European climates. 

Effectiveness of control interventions for Aedes-borne viral infections in the European context also need further 
assessment. The most effective methods for promoting sustained behaviour change and community participation in 
vector control efforts in diverse European cultural contexts are not well defined and neither is the efficacy of vector 
control methods, such as the use of insecticide, the more innovative sterile insect technique, or Wolbachia-based 
approaches. The cost-effectiveness and sustainability of these interventions in different ecological settings within 
the EU/EEA need rigorous evaluation. The influence of the mosquito microbiome on vector competence for Aedes-
borne viruses in European Aedes populations, and the potential for microbiome manipulation as a control strategy, 
could also be investigated. There are also gaps in knowledge on the impact of insecticide resistance on vector 
control efficacy, and in particular the prevalence and mechanisms of insecticide resistance in European Aedes 
populations, and their implications for current and future vector control strategies. 

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Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

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Ten Bosch QA, Clapham HE, Lambrechts L, Duong V, Buchy P, Althouse BM, et al. Contributions from the 
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Valentine MJ, Murdock CC, Kelly PJ. Sylvatic cycles of arboviruses in non-human primates. Parasit Vectors. 
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13.  Gossner CM, Hallmaier-Wacker L, Briet O, Haussig JM, de Valk H, Wijermans A, et al. Arthropod-borne 
diseases among travellers arriving in Europe from Africa, 2015 to 2019. Euro Surveill. 2023 Feb;28(7)  

14.  European Centre for Disease Prevention and Control (ECDC). Local transmission of dengue virus in mainland 
EU/EEA, 2010-present. Stockholm: ECDC; 2025. Available at: https://www.ecdc.europa.eu/en/all-topics-
z/dengue/surveillance-and-disease-data/autochthonous-transmission-dengue-virus-eueea 

15.  Gossner CM, Ducheyne E, Schaffner F. Increased risk for autochthonous vector-borne infections transmitted 

by Aedes albopictus in continental Europe. Euro Surveill. 2018 Jun;23(24)  

16.  Rezza G. Climate change and the spread of Aedes mosquito-borne viruses in Europe. Pathog Glob Health. 

2024 Jun;118(4):358-9  

17.  Appassakij H, Khuntikij P, Kemapunmanus M, Wutthanarungsan R, Silpapojakul K. Viremic profiles in 

asymptomatic and symptomatic chikungunya fever: a blood transfusion threat? Transfusion. 2013 Oct;53(10 
Pt 2):2567-74  

18.  Staples JE, Hills SL, Powers AM. Chikungunya. In: US CDC Yellow Book: Health Information for International 

Travel. Atlanta: CDC; 2024. Available at: https://wwwnc.cdc.gov/travel/yellowbook/2024/infections-
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t%20pains 

19.  Brito C, Falcão MB, de Albuquerque M, Cerqueira-Silva T, Teixeira MG, Franca RFO. Chikungunya: From 

Hypothesis to Evidence of Increased Severe Disease and Fatalities. Viruses. 2025 Jan 3;17(1)  

20.  Thannickal SA, Battini L, Spector SN, Noval MG, Álvarez DE, Stapleford KA. Changes in the chikungunya virus 
E1 glycoprotein domain II and hinge influence E2 conformation, infectivity, and virus-receptor interactions. J 
Virol. 2024 Jul 23;98(7):e0067924  

21.  Thiberville SD, Moyen N, Dupuis-Maguiraga L, Nougairede A, Gould EA, Roques P, et al. Chikungunya fever: 

epidemiology, clinical syndrome, pathogenesis and therapy. Antiviral Res. 2013 Sep;99(3):345-70  

22.  Manore CA, Hickmann KS, Xu S, Wearing HJ, Hyman JM. Comparing dengue and chikungunya emergence and 

endemic transmission in A. aegypti and A. albopictus. J Theor Biol. 2014 Sep 7;356:174-91  

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ECDC GUIDANCE 

23.  Gallian P, de Lamballerie X, Salez N, Piorkowski G, Richard P, Paturel L, et al. Prospective detection of 

chikungunya virus in blood donors, Caribbean 2014. Blood. 2014 Jun 5;123(23):3679-81  

24.  European Centre for Disease Prevention and Control (ECDC). Factsheet for health professionals about 
chikungunya. Stockholm: European Centre for Disease Prevention and Control; 2015. Available at: 
https://www.ecdc.europa.eu/en/chikungunya/facts/factsheet 

25.  Musso D, Gubler DJ. Zika Virus. Clin Microbiol Rev. 2016 Jul;29(3):487-524  

26.  Baud D, Gubler DJ, Schaub B, Lanteri MC, Musso D. An update on Zika virus infection. Lancet. 2017 Nov 

4;390(10107):2099-109  

27.  Giron S, Franke F, Decoppet A, Cadiou B, Travaglini T, Thirion L, et al. Vector-borne transmission of Zika virus 

in Europe, southern France, August 2019. Euro Surveill. 2019 Nov;24(45)  

28.  Barjas-Castro ML, Angerami RN, Cunha MS, Suzuki A, Nogueira JS, Rocco IM, et al. Probable transfusion-

transmitted Zika virus in Brazil. Transfusion. 2016 Jul;56(7):1684-8  

29.  European Centre for Disease Prevention and Control (ECDC). Local transmission of chikungunya virus in 

mainland EU/EEA, 2007–present. Stockholm: ECDC; 2025. Available at: 
https://www.ecdc.europa.eu/en/infectious-disease-topics/chikungunya-virus-disease/surveillance-and-
updates/local-transmission 

30.  Riccardo F, Venturi G, Di Luca M, Del Manso M, Severini F, Andrianou X, et al. Secondary Autochthonous 

Outbreak of Chikungunya, Southern Italy, 2017. Emerg Infect Dis. 2019 Nov;25(11):2093-5  

31.  European Centre for Disease Prevention and Control (ECDC). Introduction to the Annual Epidemiological 
Report. Stockholm: ECDC; 2024. Available at: https://www.ecdc.europa.eu/en/surveillance-and-disease-
data/annual-epidemiological-reports/introduction-annual 

32.  European Union (EU). Regulation (EU) 2017/746 of the European Parliament and of the Council of 5 April 

2017 on in vitro diagnostic medical devices and repealing Directive 98/79/EC and Commission Decision  
2010/227/EU, (2017). Available at: https://eur-lex.europa.eu/legal-content/EN/ALL/?uri=CELEX:32017R0746 

33.  European Centre for Disease Prevention and Control (ECDC). ECDC policy on scientific integrity and 

independence. Stockholm: ECDC; 2023. Available at: https://www.ecdc.europa.eu/en/publications-data/ecdc-
policy-scientific-integrity-and-independence 

34.  European Union (EU). Directive 2002/98/EC of the European Parliament and of the Council of 27 January 

2003 setting standards of quality and safety for the collection, testing, processing, storage and distribution of 
human blood and blood components and amending Directive 2001/83/EC, (2003). Available at: https://eur-
lex.europa.eu/eli/dir/2002/98/oj/eng 

35.  World Health Organization (WHO). A guide to establishing a national haemovigilance system. Geneva: WHO; 
2016. Available at: https://iris.who.int/bitstream/handle/10665/250233/9789241549844-eng.pdf?sequence=1 

36.  European Centre for Disease Prevention and Control (ECDC). Guidelines for the surveillance of invasive 

mosquitoes in Europe. Stockholm: ECDC; 2012. Available at: 
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37.  European Union (EU). Commission Implementing Decision (EU) 2018/945 of 22 June 2018 on the 

communicable diseases and related special health issues to be covered by epidemiological surveillance as well 
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content/EN/TXT/?uri=CELEX%3A32018D0945&qid=1750850583311 

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Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

Annex 1. Links to further information on 
surveillance, preparedness and response 
(control) actions against Aedes-borne viral 
diseases and their vectors 

Disease surveillance 
ECDC Annual Epidemiological Reports: https://www.ecdc.europa.eu/en/publications-data/monitoring/all-annual-
epidemiological-reports 

ECDC Surveillance Atlas of Infectious Diseases: https://www.ecdc.europa.eu/en/surveillance-atlas-infectious-
diseases 

Surveillance systems overviews: https://www.ecdc.europa.eu/en/surveillance-and-disease-data/annual-
epidemiological-reports/introduction-annual 

Information on Aedes-borne viral diseases 
Chikungunya virus disease – ECDC webpage: https://www.ecdc.europa.eu/en/chikungunya-virus-disease 

Dengue – ECDC webpage: https://www.ecdc.europa.eu/en/dengue 

Factsheet on Zika virus disease. – ECDC Factsheet: https://www.ecdc.europa.eu/en/zika-virus-
infection/facts/factsheet 

Factsheet for health professionals on chikungunya – ECDC Factsheet: 
https://www.ecdc.europa.eu/en/chikungunya/facts/factsheet 

Factsheet for health professionals on dengue – ECDC Factsheet: https://www.ecdc.europa.eu/en/dengue-
fever/facts 

Zika virus disease – ECDC webpage: https://www.ecdc.europa.eu/en/zika-virus-disease 

Laboratory diagnosis 
Laboratory testing for dengue virus – WHO interim guidance: 
https://iris.who.int/bitstream/handle/10665/381187/B09394-eng.pdf?sequence=1 

Preparedness and response 
Global strategic preparedness, readiness and response plan for dengue and other Aedes-borne arboviruses, 
2024−2025 – WHO plan: https://www.who.int/publications/m/item/global-strategic-preparedness--readiness-and-
response-plan-for-dengue-and-other-aedes-borne-arboviruses 

Vector management (entomological surveillance and control 
activities) 
AIM-COST guideline list – A collection of guideline documents used for monitoring/surveillance and control of 
Aedes invasive mosquitoes in Europe and neighbouring countries. https://www.aedescost.eu/GuidelineList 

A spatial modelling method for vector surveillance – ECDC technical report: 
https://www.ecdc.europa.eu/en/publications-data/spatial-modelling-method-vector-surveillance  

Aedes aegypti – ECDC Factsheet for experts: https://www.ecdc.europa.eu/en/disease-vectors/facts/mosquito-
factsheets/aedes-aegypti 

Aedes albopictus – ECDC Factsheet for experts: https://www.ecdc.europa.eu/en/disease-vectors/facts/mosquito-
factsheets/aedes-albopictus 

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ECDC GUIDANCE 

Aedes japonicus – ECDC Factsheet for experts: https://www.ecdc.europa.eu/en/disease-vectors/facts/mosquito-
factsheets/aedes-japonicus 

Aedes koreicus – ECDC Factsheet for experts: https://www.ecdc.europa.eu/en/disease-vectors/facts/mosquito-
factsheets/aedes-koreicus 

AedesRisk – A tool to support the decision-making process for surveillance and vector control of dengue, 
chikungunya and Zika virus disease in Europe: https://shinyapps.ecdc.europa.eu/shiny/AedesRisk/ 

ARBOCARTO – A software package for predictive mapping of population densities of Aedes mosquitoes: 
https://www.arbocarto.fr/en 

Determining discriminating concentrations of insecticides for monitoring resistance in mosquitoes – Report of a 
multi-centre laboratory study and WHO expert consultations: 
https://www.who.int/publications/i/item/9789240045200 

ECDC Guidelines for the surveillance of invasive mosquitoes in Europe: 
https://www.ecdc.europa.eu/en/publications-data/guidelines-surveillance-invasive-mosquitoes-europe 

Guidelines for laboratory and field testing of mosquito larvicides – WHO guidelines: 
https://apps.who.int/iris/handle/10665/69101 

Integrated Aedes management for the control of Aedes-borne diseases – Journal article: 
https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0006845  

Invasive mosquito surveillance effort over 2015–2019 – ECDC map: https://www.ecdc.europa.eu/en/publications-
data/invasive-mosquito-surveillance-effort-2015-2019  

Manual on prevention of establishment and control of mosquitoes of public health importance in the WHO 
European Region (with special reference to invasive mosquitoes) – WHO manual: 
https://iris.who.int/handle/10665/343056 

Monitoring and managing insecticide resistance in Aedes mosquito populations – WHO Interim guidance for 
entomologists: http://apps.who.int/iris/bitstream/10665/204588/2/WHO_ZIKV_VC_16.1_eng.pdf 

Moskeytool – Key to help to identify mosquitoes of the Euro-Mediterranean area: 
https://www.onehealthsecure.com/entomology-tools-0/moskeytool 

Mosquito alert: leveraging citizen science to create a GBIF mosquito occurrence dataset – Journal article: 
https://doi.org/10.46471%2Fgigabyte.54 

Mosquito maps – Landing page of ECDC and EFSA mosquito distribution maps: 
https://www.ecdc.europa.eu/en/disease-vectors/surveillance-and-disease-data/mosquito-maps 

Organisation of vector surveillance and control in Europe – ECDC Technical Report: 
https://www.ecdc.europa.eu/en/publications-data/organisation-vector-surveillance-and-control-europe 

Practical management plan for invasive mosquito species in Europe: Asian tiger mosquito (Aedes albopictus) – 
Journal article: 
https://www.sciencedirect.com/science/article/pii/S1477893920301599?casa_token=IiwoLEYWz2sAAAAA:HE_3ogJ
nIpW2-RX1Wf2LwE4cYt_a53P3pOYOEH8PCtViHkQZOFn9Vcgst52eh-fdr7O_Urgn 

Recommendations for standard operating procedures (SOPs) development for vector (mosquito) surveillance and 
control activities at ports and airports – Project report of EU Healthy Gateways: 
https://www.healthygateways.eu/Portals/0/plcdocs/D9_2_EU_HG_SOPs.pdf?ver=2023-02-01-181716-890 

Reducing Aedes albopictus breeding sites through education: A study in urban area. – Journal article: 
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0202451 

Seasonal active surveillance for invasive mosquitoes over 2017–2019 – ECDC map: 
https://www.ecdc.europa.eu/en/publications-data/seasonal-active-surveillance-invasive-mosquitoes-2017-2019 

Seasonal monitoring of Aedes albopictus: practical applications and outcomes – Journal article: 
https://www.izs.it/vet_italiana/Collana_di_Monografie/Mon23_5_Gavaudan.pdf 

Techniques to detect insecticide resistance mechanism – WHO field and laboratory manual: 
https://apps.who.int/iris/handle/10665/83780 

The importance of vector abundance and seasonality – ECDC technical report: 
https://www.ecdc.europa.eu/en/publications-data/importance-vector-abundance-and-seasonality  

Two invasions at once: update on the introduction of the invasive species Aedes aegypti and Aedes albopictus in 
Cyprus–a call for action in Europe. – Journal article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10540676/ 

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Guidance for assessing the risk of locally-acquired Aedes-borne viral diseases in the EU/EEA 

VEClim – An example of an applied model of disease risk: https://veclim.com/Methods/Mobile/TigerMosquito  

Vector distribution modelling – ECDC technical report: https://www.ecdc.europa.eu/en/infectious-disease-
topics/related-public-health-topics/disease-vectors/prevention-and-control 

Vector surveillance and control at ports, airports, and ground crossings – WHO guidelines: 
https://www.who.int/publications/i/item/9789241549592 

VectorNet: collaborative mapping of arthropod disease vectors in Europe and surrounding areas since 2010 – 
Journal article: https://www.eurosurveillance.org/content/10.2807/1560-7917.ES.2023.28.26.2200666 

VectorNet – The European network for medical and veterinary entomology: https://www.ecdc.europa.eu/en/about-
us/partnerships-and-networks/disease-and-laboratory-networks/vector-net 

29 

European Centre forDisease 
Prevention and Control (ECDC)

Gustav III:s Boulevard 40 
16973 Solna, Sweden

Tel. +46 858 60 10 00
ECDC.info@ecdc.europa.eu

www.ecdc.europa.eu