Health Hygiene & Sanitation

Lesson 34 : Prevention And Control Of Infectious Diseases


Definition: A disinfectant or germicide is a substance which destroys harmful microbes (not usually spores) with the object of preventing transmission of disease. Disinfectants are suitable for application only to inanimate objects. An antiseptic is a substance which destroys or inhibits the growth of micro-organisms. Antiseptics are suitable for application to living tissues. A disinfectant in low concentrations or dilutions can act as an antiseptic. A deodorant is a substance which suppresses or neutralizes bad odours. e.g. lime and bleaching powder. A detergent is a surface cleansing agent which acts by lowering surface tension, e.g. soap which removes bacteria along with dirt. Sterilization is the process of destroying all life including spores. Disinfection is the killing of infectious agents outside the body by direct exposure to chemical or physical agents. It can refer to the action of antiseptics as well as disinfectants.

Types of Disinfection

  1. Concurrent disinfection: It is the application of disinfective measures as soon as possible after the discharge of infectious material from the body of an infected person, or after the soiling of articles with such infectious discharges. Concurrent disinfection consists of usually disinfection of urine, feces, vomit, contaminated linen, clothes, hands, dressings, aprons, gloves, etc throughout the course of an illness

  2. Terminal disinfection: It is the application of disinfective measures after the patient has been removed by death or to a hospital or has ceased to be a source of infection or after other hospital isolation practices have been discontinued. Terminal disinfection is now scarcely practiced; terminal cleaning is considered adequate along with airing and sunning of rooms, furniture and bedding.

  3. Recurrent (prophylactic) disinfection: Disinfection by chlorination of water, pasteurization of milk and hand-washing may be cited as examples of precurrent disinfection.

Natural Agents : Sunlight and Air

Physical Agents: Burning, Hot air, Boiling, Autoclaving, Radiation

Chemical Agents :

  • Phenol and related compounds-Pure phenol or carbolic acid, Crude phenol, Cresol, Cresol emulsions, Chlorhexidine (hibitane), Hexachlorphane, Dettol (chloroxylenol)
  • Quarternary ammonia compounds-Cetrimide and Savlon
  • Halogens and their compounds- Bleaching powder, Sodium hypochlorite, Halazone tablets, Iodine, Iodophors,
  • Alcohols- Ethyl alcohol, Isopropyl alcohol, Formaldehyde, Lime, Ethylene oxide
Last modified: Thursday, 26 April 2012, 9:19 AM