Chapter 11, Problem 1NP

Summary Introduction

Introduction:

Infection is the whole process of entry of the disease-causing agents in the body of an organism, their multiplication and the production of toxins by them. Infections can be caused by bacteria, viruses, prions, nematodes, arthropods, and various other infectious agents.

Answer to Problem 1NP

Correct answer:

The progression of infection is promoted by the proper portal of entry, lack of previous exposure to infection, and host immunosuppression. Therefore, options (b), (d), and (e) are correct.

Option (b) is given as “proper portal of entry”, option (d) is given as “no previous exposure to this infection”, and option (e) is given as “host immunosuppression”.

Explanation of Solution

Justify reason for the correct statement:

The way through which infectious agent enters the body of the host is known as the portal of entry. This provides access to the tissues where infectious agents multiply. The portal of entry plays an important role, for example, influenza virus enters the respiratory tract through the inhalation of droplets.

Without prior exposure to the infection, the body does not have antibodies against this pathogen. It takes time to generate antibodies. The infectious agents take advantage of it and multiply at a faster rate.

Immuno-compromised and immune-suppressed individuals have a weak immune system which is not able to generate antibodies and fight against the disease. So infectious agents enter their body easily and infect different tissues.

Hence, options (b), (d), and (e) are correct.

Justify reasons for the incorrect statements:

Option (a) is given as “low microbial virulence”.

Virulence can be defined as the extent of damage that can be caused by any microbe. Low virulence refers to the low extent of the damage. This way, the pathogen cannot multiply within the body of hosts. Hence, it is a wrong answer.

Option (c) is given as “genetic profile of host resistance to microbe”.

Genetic profile of host resistance to infectious agent or microbe is not very important since the body of host responds to each of the microbes in its own manner and first exposure to the microbe is an example that genetic profile is not so important. Hence, it is a wrong answer.

Hence, options (a) and (c) are incorrect.

Conclusion

The progression of an infection depends on the correct portal of entry, no previous exposure to this infection, and host immunosuppression.