Question

Question 5 (1 point) Robert Koch's postulates don't apply to all diseases caused by microbes because: All of the answers shown Some microbes can't be cultured in laboratory media some microbes cause different symptoms under different conditions Some microbes don't cause the same disease in laboratory animals Some microbes can't be observed

Answer 1

Koch's Postulates

• The bacteria must be present in every case of the disease.
• The bacteria must be isolated from the host with the disease and grown in pure culture.
• The specific disease must be reproduced when a pure culture of the bacteria is inoculated into a healthy susceptible host.
• The bacteria must be recoverable from the experimentally infected host.

There are some exceptions to the postulates such as

1) Some microorganisms can't be cultivated into the culture media. For example :- Treponema pallidum(syphilis), Mycobacterium leprae(leprosy), Rickettsia, Chlamydia, viruses.

2) one disease may involve several pathogens. For example :- Meningitis can be caused by Bacteria, fungus, virus

3) One pathogen can cause several diseases. For example :- Streptococcus pyogenes - Scarlet fever, sore throat, skin infections etc.

4) Some microorganisms don't cause same disease in the test animals. For example :- leprosy doesn't occur in animals.

So, all the options given in the questions are the exceptions to the Koch postulates & hence option (a)"All of the answers shown" are correct

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