Biological specificity of disease

Koch’s contribution to medical biology continues when he further established the fact of “Biological Specificity”. Now what actually Biological Specificity” means? It actually shows that a particular disease can be produced by a particular bacterium only. Other bacteria either do not produce any disease or may produce another form of disease following inoculation. He established this by trying to produce “Anthrax” disease from different types of spore forming bacillus like hay bacillus.
In the same time another interesting thing happened. J. Joubert, a person with profound medical knowledge collaborated with Pasteur and they together also started working with anthrax, a serious problem at that time. They were unaware of Koch’s advancement but the conclusions made by them were similar to that of Koch, further confirming Koch’s theory.

Koch’s postulate

Robert Koch thus has established the relationship between a specific microorganism and a specific disease. The criteria for this can be generalized as: -

1. The microorganism must be present in every case of the disease;
2. The microorganism must be isolated from the diseased host and grown in pure culture;
3. The specific disease must be reproduced when a pure culture of the microorganism and inoculated into a healthy susceptible host and
4. The microorganism must be recoverable once again from the experimentally infected host.

These criteria has been generalized as Koch’s postulate to show respect to Koch’s work.