Koch's Postulates
to Identify the Causative Agent of an Infectious Disease


Koch's Postulates

Four criteria that were established by Robert Koch to identify the causative agent of a particular disease, these include:

  1. the microorganism or other pathogen must be present in all cases of the disease

  2. the pathogen can be isolated from the diseased host and grown in pure culture

  3. the pathogen from the pure culture must cause the disease when inoculated into a healthy, susceptible laboratory animal

  4. the pathogen must be reisolated from the new host and shown to be the same as the originally inoculated pathogen

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