Question

1. What is an infectious dose? Would a more virulent organism have a higher or lower infectious dose? What can affect the infectious dose of a microbe?

Answer 1

• Infectious dose:The amount of pathogen or dose that required to infect the host is known as infectious dose.
• If a organism if more virulent that means the organism can harm the host more.So that it would need a lower infectious dose to harm the host.
• There are mainly on two parameters which can affect the infectious dose of a microbe-

(a) Mode of action: The degree of virulence of any pathogen or microbe depends on the mechanism of action of the microbe or pathogen. That means how it is infecting the host locally or distance place.If the pathogen or microbe acts distance place from the place of infection then it can harm the host more effectively or we can say that the pathogen is more virulent.

(b)Immunity of the host: The degree of of virulence of the microbe also depends on the immunity of the host. If the host is immune against that microbe then the microbe will be unable to infect the host that much manner if the host have not been immune against the microbe.