Vector-borne diseases are diseases caused by bacteria, parasites and viruses that are transmitted by the bite of infected arthropod vectors, such as mosquitos, ticks, sand flies and fleas. Vectors can transmit pathogens from animals to humans, between humans and between animals. The presence of the diseases depends on the presence of vectors and animal/human reservoirs, which is influenced by many factors, such as climate change, international travel, trade and land use.

In Europe, the highest disease burden in humans is caused by tick-borne diseases, such as Lyme borreliosis. But mosquito-borne diseases are emerging.  

Tick-borne diseases are spread by the bite of infected ticks. Lyme borreliosis (or Lyme disease) is the most common disease transmitted through ticks. Other diseases include anaplasmosis and tick-borne encephalitis.

Mosquito-borne diseases are spread by the bite of an infected mosquito. Examples are West Nile fever, chikungunya, dengue, zika and malaria. For more information, consult the specific webpage on mosquito-borne diseases, or by disease under ‘Health topics A-Z’. 

Other vectors that can transmit pathogens and cause disease are e.g. fleas, lice, mites, sand flies, biting flies and Culicoides. Leishmaniosis, plague and rickettsiosis are examples of such infectious diseases transmitted by these vectors. These diseases are rare (and travel-related) or absent in Belgium.