CLINICAL MEDICINE

Detailed explanation-1: -Viroids: the smallest and simplest agents of infectious disease.

Detailed explanation-2: -Viruses are the smallest common pathogen. They are so small in fact that many of them actually infect bacteria. They are different from other pathogens because they cannot reproduce on their own.

Detailed explanation-3: -There are things out there even smaller than viruses. The two that scientists have discovered are called prions and viroids. A prion is (as far as we know) just a protein. Prions are proteins that can invade cells and somehow direct their own duplication, making more of the isolated proteins.

Detailed explanation-4: -Viruses are the smallest of all the microbes. They are said to be so small that 500 million rhinoviruses (which cause the common cold) could fit on to the head of a pin. They are unique because they are only alive and able to multiply inside the cells of other living things.

Detailed explanation-5: -Among all the microbes, viruses are the smallest. Viruses are living only inside the host body and are non-living outside. Viruses are pathogens and cause diseases in living organisms. Viruses have the smallest size such as 0.02 microns.