What are Koch's Postulates?

1 Answer
Oct 25, 2016

Koch's postulates are four criterion designed to establish a causative relationship between a microbe and a disease.


The postulates were formulated by Robert Koch and Friedrich Loeffler (1884).
Koch's postulates are the following :

  • The micro organism must be found in abundance in all organisms suffering from the disease, but shloud not be found in healthy organisms.
  • The micro organism shloud be isolated from a diseased organism and grown in a pure culture.
  • The cultured micro organism should cause disease when introduced into a healthy organism.
  • The micro organism should be re isolated from the innocolated , diseased experimental host and identified as being identical to the original specific causative agent.

Koch's postulates were developed in the 19 th century as general guidelines to identify pathogens that could be isolated with the techniques of a the day.
A body of evidence that satisfies Koch's postulates is sufficient but not necessary to establish causation.