State Koch's Postulates

Robert Hermann Koch was a physician, he gave 4 postulates on relationship between disease and their causative agent.

Explanation

Kochs pastulates are as follows-

Causative agents / microorganism always present in diseased individual, but should not present in healthy one. These causative microorganisms can be isolated and cultured. That cultured microorganism again can cause disease if transferred into healthy individual, and again can be reisolated and cultured. Reisolated microorganisms from this diseased individual will be same and identical as cultured and isolated from previous diseased individual.