Modes of transmission refer to the ways in which infectious agents, such as bacteria and viruses, spread from one host to another. Common modes include direct contact, where pathogens are transferred through physical touch, and indirect contact, where they spread via contaminated surfaces or objects. Airborne transmission occurs when pathogens are carried through the air in droplets or dust particles. Another mode is vector-borne transmission, where insects like mosquitoes or ticks carry pathogens from one host to another. Additionally, some diseases can be transmitted through food or water that has been contaminated. Understanding these modes helps in preventing the spread of infections.