Explanation:

German physician Robert Koch formulated the series of steps required to prove the cause of any infectious disease.

Koch first explained his method to the scientific community in articles he published on tuberculosis in the late 1800s. The postulates are as follows:

• A microbe suspected of causing a certain disease must be found in ever case of that disease.
• The suspected microbe must be isolated and grown in the laboratory, outside of the host.
• When this suspected pathogen is introduced to a healthy, susceptible host, that host must develop the disease.
• That same pathogen must then again be obtained and reisolated from that experimental host.