Vector-borne diseases

Introduction

A vector is a living organism that transmits an infectious agent from an infected animal to a human or another animal. Vectors are frequently arthropods, such as mosquitoes, ticks, flies, fleas and lice.
Vectors can transmit infectious diseases either actively or passively:

  • Biological vectors, such as mosquitoes and ticks may carry pathogens that can multiply within their bodies and be delivered to new hosts, usually by biting.
  • Mechanical vectors, such as flies can pick up infectious agents on the outside of their bodies and transmit them through physical contact.

Diseases transmitted by vectors are called vector-borne diseases. Many vector-borne diseases are zoonotic diseases, i.e. diseases that can be transmitted directly or indirectly between animals and humans. These include for example Lyme disease, tick-borne encephalitis, West Nile virus, Leishmaniosis and Crimean-Congo haemorrhagic fever.
Many vector-borne diseases are considered as emerging infectious diseases in the European Union:

  • a disease that appears in a population for the first time, or
  • that may have existed previously but is rapidly increasing in incidence or geographic range.

Some vectors are able to move considerable distances. This may affect the transmission ranges of vector-borne zoonotic diseases. Vectors can be introduced to new geographic areas for example by:

  • travel of humans and international trade;
  • animal movement, for instance of livestock;
  • migratory birds;
  • changing agricultural practices;
  • or the wind.

Other factors may play a role in their establishment and persistence in new areas, including climatic conditions.

Storymaps

EFSA has produced 36 interactive storymaps that provide user-friendly information on vector-borne diseases – from their geographical spread, to the risk of introduction in the EU to prevention and control measures. The storymaps have been developed as part of a scientific opinion that will support risk managers to prioritise control measures.

The tool that experts developed to carry out their risk assessments (Mintrisk) is publicly available and includes the data and information used by the experts to reach their conclusions. The storymaps are under revision and new versions will be updated by the end of 2021.

 36 interactive story maps

If you have any comments on the storymaps, send them to: vbd [at] efsa.europa.eu

Role

EFSA and its Panel on Animal Health and Welfare provide independent scientific advice and scientific assistance on human health and animal health-related aspects of vector-borne zoonotic diseases. EFSA monitors and analyses the situation on zoonoses, zoonotic micro-organisms, antimicrobial resistance, microbiological contaminants and food-borne outbreaks across Europe.

EFSA works with European Centre for Disease Prevention and Control (ECDC), sharing information on present and future projects on vectors and vector-borne zoonotic diseases.

Based on data collected by the EU Member States, EFSA and ECDC produce annual European Union summary reports on vector-borne zoonoses in animals and food-borne outbreaks caused by these micro-organisms.

VectorNet

VectorNet is a joint initiative of EFSA and ECDC, which started in May 2014, and is now in its second iteration (2019-2023). VectorNet supports the collection of data on vectors and pathogens in vectors, related to both animal and human health.

ECDC and EFSA maintain a common database on the presence and distribution of vectors and pathogens in vectors in Europe and the Mediterranean basin, through a network of medical and veterinary experts and organisations.

The project also provides ad-hoc scientific advice to ECDC and EFSA on technical questions about vector surveillance and vector-borne diseases in humans and animals.

The project will contribute to improving preparedness and response to vector-borne diseases in the European Union. Stay up to date on the latest activities of VectorNet and subscribe to our newsletter.

Vector maps

The VectorNet project database of ECDC and EFSA provides information on the European distribution of several mosquitoes, ticks, sandfly and biting midges species, which can be vectors of pathogens affecting human or animal health. The maps are based on confirmed data (published and unpublished) provided by experts, and do not represent the official position of the countries.

Mosquito maps The maps show the current known distribution of several invasive and native mosquito species in Europe at 'regional' administrative level (NUTS3).
Tick maps The maps show the current known distribution of several tick species in Europe at 'regional' administrative level (NUTS3).
Sandfly maps The maps show the current known distribution of several sandfly species in Europe at 'regional' administrative level (NUTS3).
Biting midge maps The maps show the current known distribution of several biting midge species in Europe at ‘regional’ administrative level (NUTS3).

Please contact vectornet [at] ecdc.europa.eu if you have relevant information pertaining the vector distribution maps.

EU Framework

According to EU legislation, many infectious diseases have to be notified by Member States to either national authorities or the European Commission. They are managed by various control, eradication and prevention measures. EU policy on communicable diseases focuses on surveillance, rapid detection and rapid response.

An EU network for the epidemiological surveillance and control of communicable diseases has been in place since 1999. EU surveillance includes some important vector-borne zoonotic diseases, such as malaria, the West Nile virus and yellow fever. In addition, ECDC has a specific programme on emerging and vector-borne diseases.

In the area of animal health, one of the key elements of the Community Animal Health Policy is the early detection of exotic, new and emerging disease threats.