Which of the following is not one of Koch's postulates?
a. The same pathogen must be present in every case of the disease.
b. The pathogen must be isolated and grown in pure culture from the diseased host.
c. The pathogen from pure culture must cause the disease when inoculated into a healthy, susceptible laboratory animal.
d. The disease must be transmitted from a diseased animal to a healthy, susceptible animal by direct contact.
e. The pathogen must be isolated in pure culture from an experimentally infected lab animal.

Verified step by step guidance

1. Identify the four original Koch's postulates.
2. Review each option provided in the problem.
3. Compare each option to the original Koch's postulates.
4. Determine which option does not align with the original postulates.
5. Select the option that is not one of Koch's postulates.

Key Concepts

Koch's Postulates

Koch's postulates are a set of criteria established by Robert Koch to identify the causative agents of infectious diseases. They include the requirement that the same pathogen must be present in every case of the disease, must be isolated and grown in pure culture, and must cause the disease when introduced to a healthy host. These postulates laid the foundation for microbiology and infectious disease research.

Pathogen Isolation

Pathogen isolation refers to the process of separating a specific microorganism from a mixed culture or from the tissues of an infected host. This is crucial for studying the pathogen's characteristics and confirming its role in disease. Pure culture techniques allow researchers to analyze the pathogen's behavior, virulence, and response to treatments.

Experimental Infection

Experimental infection involves deliberately introducing a pathogen into a healthy, susceptible host to observe the resulting disease. This method is essential for establishing a causal relationship between a pathogen and a disease, as it demonstrates that the isolated pathogen can reproduce the disease symptoms. It is a key step in validating Koch's postulates.