The following statements are true:
The microbe must be present in individuals suffering from the disease and absent from healthy individuals.
If organisms from the pure culture are injected into a healthy experimental animal, the disease symptoms should appear.
The microbe must be isolated and grown in pure culture.
Note: The question is incomplete. The complete question is given below:
Evaluate these statements about Koch's postulates, which are used to establish a causative link between a specific microbe and a specific disease. Which of them are true? Select all that apply.
The microbe must be present in individuals suffering from the disease and absent from healthy individuals.
The microbe does not have to be isolated from the experimental animal as long as the disease is present.
If organisms from the pure culture are injected into a healthy experimental animal, the disease symptoms should appear.
The microbe must be isolated and grown in pure culture.
Explanation:
Robert Koch, a German Physician, in 1884 postulated the following four criteria in order to establish a causative relationship between a microbe and a disease;
The microorganism must be found in abundance in all organisms suffering from the disease, but should not be found in healthy organisms.
The microorganism must be isolated from a diseased organism and grown in pure culture.
The cultured microorganism should cause disease when introduced into a healthy organism.
The microorganism must be reisolated from the inoculated, diseased experimental host and identified as being identical to the original specific causative agent.
From the above, the following out of the statements are true:
The microbe must be present in individuals suffering from the disease and absent from healthy individuals.
If organisms from the pure culture are injected into a healthy experimental animal, the disease symptoms should appear.
The microbe must be isolated and grown in pure culture.
