Vector transmission occurs most often from insect bites from mosquitoes, flies, fleas, and ticks. There are two sub-categories of vectors: "mechanical" (an insect transmits the pathogen to a host without the insect itself being affected) and "biological" (reproduction of the pathogen occurs within the vector before the pathogen is transmitted to a host). To give a few examples, "Morbillivirus" (measles) is transmitted from an infected human host to a susceptible host as they are transmitted by respiration through airborne transmission. "Campylobacter" (campylobacteriosis) is a common bacterial infection that is spread from human or non-human reservoirs by vehicles such as contaminated food and water. "Plasmodium falciparum" (malaria) can be transmitted from an infected mosquito, an animal (non-human) reservoir, to human host by biological vector transmission.