Vectors are organisms that transmit pathogens and parasites from one infected person (or animal) to another, causing serious diseases in human populations.
These diseases are commonly found in tropical and sub-tropical regions and places where access to safe drinking-water and sanitation systems is problematic.
Vector-borne diseases account for 17% of the estimated global burden of all infectious diseases. The most deadly vector-borne disease, malaria, caused an estimated 627,000 deaths in 2012.
However, the world's fastest growing vector-borne disease is dengue, with a 30-fold increase in disease incidence over the last 50 years.
Source: World Health Organization