Vector
Parasitology · Epidemiology · Entomology
Say it: VEK-tur
In disease biology, a vector is a living organism, often a bloodsucking insect or tick, that carries a pathogen from one host to another.
Also: vectors
Definition
What is a vector?
A vector is a living organism that carries an infectious agent from one host to another, such as from an infected animal or person to a healthy one. Most vectors are bloodsucking arthropods: a mosquito, tick or fly picks up a pathogen while feeding on an infected host and passes it on at a later bite. Mosquitoes carry malaria, dengue, Zika and yellow fever; ticks carry Lyme disease; sandflies carry leishmaniasis; tsetse flies carry sleeping sickness; and fleas carry plague. Freshwater snails act as vectors for schistosomiasis.
In many cases the pathogen must develop or multiply inside the vector before it can be passed on, as Plasmodium does inside Anopheles mosquitoes, so the vector is a true stage in its life cycle rather than a passive carrier. Vector-borne diseases make up a large share of the world's infectious disease, and their range is shifting as climate, travel, trade and urban growth change where vectors can live. Control often targets the vector itself, with bed nets, insecticides and removal of breeding sites.
In molecular biology the word has a second meaning: a DNA molecule, such as a plasmid or a modified virus, used to carry a gene into a cell for cloning or gene therapy.
Word parts
Where does the word “vector” come from?
- vect-
- carryLatin vehere, vectus
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Terms that go with it
- PlasmodiumPlasmodium is a genus of single-celled parasites, spread by Anopheles mosquitoes, that infect liver and red blood cells and cause malaria.
- ParasiteA parasite is a living thing that makes its home on or inside a host organism and feeds from it, usually causing the host harm.
- PathogenA pathogen is a microbe or other agent, such as a virus, bacterium, fungus, parasite or prion, that can cause disease in a host.
- ZoonosisA zoonosis is an infectious disease that passes between animals and people, caused by a virus, bacterium, parasite or fungus carried by animals.
- PlasmidA plasmid is a small, usually circular DNA molecule that copies itself independently of the main chromosome, found mostly in bacteria.
- Public healthPublic health is the science and practice of preventing disease and injury and promoting health across whole communities rather than individual patients.
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