kochs postulates

Koch’s Postulates or Koch’s Laws

According to Koch’postulates a microorganism can accepted as the causative agent of an infectious diseases only if the following conditions are satisfied –

  1. Postulates I (Association)

The microorganism must be found in abundance in all organism suffering from disease. (should be regularly found in the lesions of disease).

  1. Postulate II (Isolation)

The organism must be isolated from the diseased animal and grown in pure culture. (should possible to isolate the organism in pure culture from the lesions.)

  1. Postulate III (Inoculation)

The isolated microorganism should cause the same disease when inoculated into healthy animal. ( Inoculation of pure culture into suitable laboratory animal should produce the lesion of diseases.

  1. Postulate IV ( Reisolation)

The microorganism must be reisolated from the inoculated host and identify as being identical to original specific causative agent.

( It should be possible to reisolate the organism in pure culture from the lesions produce in the experimental animals.

Robert koch criteria for providing the causal relationship between microorganism and a specific disease are known as Koch’s postulates.