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Ch. 15 - Microbial Mechanisms of Pathogenicity
Tortora - Microbiology: An Introduction 14th Edition
Tortora14th EditionMicrobiology: An IntroductionISBN: 9780138200398Not the one you use?Change textbook
All textbooksTortora 14th EditionCh. 15 - Microbial Mechanisms of PathogenicityProblem 10
Chapter 15, Problem 10

Which of the following statements is true?
a. The primary goal of a pathogen is to kill its host.
b. Evolution selects for the most virulent pathogens.
c. A successful pathogen doesn't kill its host before it is transmitted.
d. A successful pathogen never kills its host.

Verified step by step guidance
1
Step 1: Understand the concept of pathogen-host interaction, where the pathogen's goal is to survive and reproduce, often by transmitting to new hosts rather than killing the current host immediately.
Step 2: Analyze option (a): 'The primary goal of a pathogen is to kill its host.' Consider that killing the host too quickly can limit transmission opportunities, so this is generally not true.
Step 3: Analyze option (b): 'Evolution selects for the most virulent pathogens.' Remember that evolution favors traits that maximize transmission, which may not always mean maximum virulence; extremely virulent pathogens may reduce their own spread.
Step 4: Analyze option (c): 'A successful pathogen doesn't kill its host before it is transmitted.' This aligns with the idea that pathogens must keep the host alive long enough to spread to new hosts, making this statement likely true.
Step 5: Analyze option (d): 'A successful pathogen never kills its host.' While some pathogens may not kill their hosts, others can be lethal but still successful if transmission occurs before death; thus, this statement is too absolute to be true.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Pathogen-Host Relationship

Pathogens interact with their hosts in ways that balance survival and reproduction. Killing the host too quickly can limit the pathogen's ability to spread, so many pathogens evolve strategies to coexist without immediate host death.
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Symbiotic Relationships

Virulence and Evolution

Virulence refers to the degree of damage a pathogen causes. Evolution tends to favor pathogens that optimize transmission, which may not always mean maximum virulence; overly virulent pathogens risk killing hosts before spreading.
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Virulence

Transmission and Pathogen Success

A pathogen's success depends on effective transmission to new hosts. Therefore, pathogens that allow their hosts to survive long enough to spread the infection are more likely to persist and evolve.
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Introduction to Pathogenic Toxins
Related Practice
Textbook Question

Which of the following does not represent the same mechanism for avoiding host defenses as the others?

a. Rabies virus attaches to the receptor for the neurotransmitter acetylcholine.

b. Salmonella attaches to the receptor for epidermal growth factor.

c. Lymphocryptovirus (mononucleosis) virus binds to the host receptor for complement protein.

d. Surface protein genes in N. gonorrhoeae mutate frequently.

e. none of the above

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Textbook Question

The Opa gene is used to identify this endotoxin-producing bacterium that grows well in the high- CO₂ conditions inside phagocytes.

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Textbook Question

Which of the following genera is the most infectious?

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Textbook Question

How can viruses and protozoa avoid being killed by the host’s immune response?

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