Contagious: Contagious refers to diseases that can be easily transmitted from person to person through direct contact, respiratory droplets, or touching contaminated surfaces.
Transmission Pathways: Transmission pathways are the routes or methods by which diseases spread among individuals. Examples include airborne transmission, waterborne transmission, or vector-borne transmission.
Diffusion: In geography, diffusion refers to the process of spreading ideas, innovations, behaviors, or phenomena across space and time. It can also apply to the spread of diseases.