Who is this man on the left our header art? That is Robert Koch, one of the most important people in the history of microbiology and exactly the kind of person who is deserving of the first post in a blog on infectious disease.
Koch is most famous for what are now termed ‘Koch’s Postulates’ which are a series of rules or parameters used to establish whether a particular microorganism is the causative agent in a particular disease.
- The microorganism must be found in abundance in all animals suffering from the disease, but should not be found in healthy animals
- The microorganism must be able to be found within the diseased organism, collected and grown in pure culture
- The cultured microorganism should be able to be used to inoculate a new, healthy animal and the result of the inoculation should be the same disease as seen in originally sick animals
- The microorganism must be reisolated from the inoculated animal and identified as being identical to the original specific causative agent.
These postulates are the foundation of infectious disease research as they set the boundaries on our definition of infectious disease. But that doesn’t mean that all infectious pathogens played by the rules.
Even in Koch’s time some organisms were known to be ‘carried’ by the host without the host showing any signs of disease, this violates Koch’s first postulate. The second postulate can also be tricky as not all infectious diseases can be readily cultured even now. We can even run into problems with the third postulate as the animal to be inoculated will obviously be a different animal to the one the microorganism was isolated from originally. The animal to be inoculated may have a stronger immune system or a genetic advantage when dealing with this microorganism, the organism itself may change whilst being cultured and become less virulent and even the different nutritional backgrounds of he animals may contribute to different outcomes that may violate Koch’s Postulates.
Despite all this it is considered that Koch’s Postulates speak to the majority of cases and if a body of work supports the postulates in principle the microorganism can be said to be the causative agent of disease.
For his troubles Koch was awarded the Nobel Prize for medicine in 1905 and worldwide is celebrated for his work in the fields of agricultural anthrax, solid media technology, Tuberculosis, Malaria and a number of parasitic worms.
I want to say a very heartfelt thank you to the artist who put the header together for us. Her name is Cazy and I contacted her after she helped me out with some other photoshop work. Do you like her work? If you do you can check out more of her work (and maybe able to contact her) at http://s970.photobucket.com/albums/ae186/cazylein/png/?albumview=grid
If you dont well what are you waiting for, check out the artwork tab at the top of the page and design us a header and maybe you can be our featured artist!