A disease spreads through vector-borne transmission when it's transferred to a person by a mosquito or another blood-sucking arthropod.
A vector is a carrier, and borne means "transported by." When diseases are carried and transmitted by insects, scientists call that vector-borne transmission. Mosquitoes are responsible for a huge amount of vector-borne transmission to humans, including dengue and malaria. Other arthropods that act as vectors are ticks, flies, and fleas, which transmit illnesses like Lyme disease and the bubonic plague.