Definition: Classifications of how different infections are spread

  • person-to-person spread
  • air-borne
  • water-borne
  • food-borne
  • vector-bore


  • direct contact
  • indirect contact

Examples of directly and indirectly transmitted infections, Giesecke
Direct Transmission Indirect Transmission
Mucous membrane to mucous membrane - sexually transmitted disease Water - hepatitis A
Across placenta - toxoplasmosis "Proper" air-borne - chicken-pox
Transplants, including blood - hepatitis B Food-borne - salmonella
Skin to skin- herpes type I Vectors - malaria
Sneezes, coughs - influenza Objects - scarlet fever (e.g. on toys in nursery)