Which type of transmission involves a living organism carrying a disease from one infected person to another?

The correct answer is vector-borne transmission because it specifically refers to the mechanism where a living organism, often an insect or another animal, carries pathogens from one host to another. In this context, the "vector" (such as mosquitoes, ticks, or fleas) serves as a vehicle for the disease-causing organism, effectively facilitating its transmission between infected and susceptible individuals.

Vector-borne transmission is significant in the study of infectious diseases because it highlights the role of biological agents in disease spreading. For instance, diseases like malaria, dengue fever, and Lyme disease are primarily transmitted through vectors that bite and subsequently transfer pathogens.

This distinguishes it from other forms of transmission. Airborne transmission involves the spread of pathogens through aerosols that can remain suspended in the air and be inhaled, while common vehicle transmission occurs through shared contaminated substances, like food or water. Droplet transmission relates to the spread of pathogens via respiratory droplets expelled during coughing or sneezing. Each of these transmission methods does not involve a living organism as a direct carrier between infected persons.