The term “pest” is a very broad term that basically defines organisms that are an annoyance to humans because they are in places we don’t want them to be, like our homes. Examples of pests include: ants, bed bugs, lice, mosquitoes, and wasps.
Vectors are organisms that transmit disease to humans. Examples of vectors include: mosquitoes, ticks, and fleas. In most circumstances, vectors are pests.