1. Pathogen: The microbes that cause disease are called pathogens. Example: Bacteria, virus, etc.
2. Vector: A vector is an organism that carries disease causing microbes (pathogens) from one host to another. They are the carriers of infection. Example: Mosquito, housefly, etc.
3. Droplet infection: Droplet infection is an infection transmitted from one individual to another by droplets of saliva or nasal moisture during coughing, sneezing, speaking and spitting.
4. Infectious diseases: The diseases which spread from an infected person to a healthy person through air, water, foQd, soil or physical contact are called communicable diseases. Example: Common cold, chickenpox, etc.
