Hello Everyone,
Today I will be talking about River's Postulate.
Diseases at one time were thought to be caused by wrath of the gods, configuration of stars or miasmas. After a real struggle that occurred not so many years ago, certain maladies were shown to be induced either by small animals or minute plants, e.g., protozoa, fungi, bacteria and spirochetes. Indeed, the victory was so great that most workers in time began to consider that all infectious diseases, including those whose incitants had not been discovered, must be caused by agents similar to those already recognized.
In my previous post I have mentioned about Koch's postulates.
In order to prove an infectious etiology for a disease Koch’s postulates require that one isolate a bacterium from a diseased animal or plant and when reintroduced it causes the same disease. Rivers’ postulates basically require the same for viral diseases.
However virus detection is not straight forward and proper identification has a bearing on relating a particular virus to particular disease. In classical sense, Koch’s postulates can not be applied to viral disease because unlike bacterial cells, viruses cannot be cultivated in pure cultures. to overcome circumvent this problem Thomas M River in 1937 expanded Koch’s postulates to include viruses as follows:
It is obvious that Koch's postulates have not been satisfied in viral diseases. Moreover, it is equally evident that proof of the etiological significance of viruses has been obtained without their satisfaction. Such a statement, however, does not imply that certain conditions do not have to be met before the specific relation of a virus to a disease is established. The conditions are:
(a) A specific virus must be found associated with a disease with a degree of regularity.
(b) The virus must be shown to occur in the sick individual not as an incidental or accidental finding but as the cause of the disease under investigation.
Nevertheless, there are certain differences. In the first place, it is not obligatory to demonstrate the presence of a virus in every case of the disease produced by it. Secondly, the existence of virus carriers is recognized. Finally, it is not essential that a virus be grown on lifeless media or in modified tissue cultures.
Thank you,
with love
-Dixy
Today I will be talking about River's Postulate.
Diseases at one time were thought to be caused by wrath of the gods, configuration of stars or miasmas. After a real struggle that occurred not so many years ago, certain maladies were shown to be induced either by small animals or minute plants, e.g., protozoa, fungi, bacteria and spirochetes. Indeed, the victory was so great that most workers in time began to consider that all infectious diseases, including those whose incitants had not been discovered, must be caused by agents similar to those already recognized.
In my previous post I have mentioned about Koch's postulates.
In order to prove an infectious etiology for a disease Koch’s postulates require that one isolate a bacterium from a diseased animal or plant and when reintroduced it causes the same disease. Rivers’ postulates basically require the same for viral diseases.
However virus detection is not straight forward and proper identification has a bearing on relating a particular virus to particular disease. In classical sense, Koch’s postulates can not be applied to viral disease because unlike bacterial cells, viruses cannot be cultivated in pure cultures. to overcome circumvent this problem Thomas M River in 1937 expanded Koch’s postulates to include viruses as follows:
- Filtrates of infectious material shown not to contain bacterial or other cultivable organisms must produce the disease or it's counterpart ,
- or filtrates must produce certain Antibodies in appropriate animals.
This is known to as River's Postulate.
It is obvious that Koch's postulates have not been satisfied in viral diseases. Moreover, it is equally evident that proof of the etiological significance of viruses has been obtained without their satisfaction. Such a statement, however, does not imply that certain conditions do not have to be met before the specific relation of a virus to a disease is established. The conditions are:
(a) A specific virus must be found associated with a disease with a degree of regularity.
(b) The virus must be shown to occur in the sick individual not as an incidental or accidental finding but as the cause of the disease under investigation.
Nevertheless, there are certain differences. In the first place, it is not obligatory to demonstrate the presence of a virus in every case of the disease produced by it. Secondly, the existence of virus carriers is recognized. Finally, it is not essential that a virus be grown on lifeless media or in modified tissue cultures.
Thank you,
with love
-Dixy
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