Download Principles of Disease 1. Define pathogen, infection, and disease. 2

Biology 240
Clark College
Kibota 1
Principles of Disease
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Define pathogen, infection, and disease.
Compare and contrast normal microbiota (also called normal or resident flora) and
opportunistic pathogens.
Why do usually nonpathogenic bacteria sometimes become pathogenic?
a.
Know that some nonpathogenic bacteria become pathogenic if they are introduced
into the wrong locations in the human body.
b. Know that some strains of nonpathogenic bacteria are genetically-altered (via
transformation by plasmid or transduction by lysoegnic bacteriophage) to gain ability
to produce toxins.
Understand and describe the following steps (mechanisms) that underlie pathogenicity:
a.
Host colonization
i.
Compare and contrast nonspecific and specific adherence.
• What are adhesins?
ii. Know that bacterial invasion may often involves invasion into host tissues and
less frequently involves invasion into host cells.
• Know that invasion is mediated by specific compounds called invasins.
• Know the actions of the following invasins:
o Hyaluronidase
o Collagenase
o Streptokinase, Staphylokinase
o Neuraminidase
b. Evasion of host defenses
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How do bacteria avoid phagocytosis?
• Know the actions of streptolysins and staphylococcal leukocidins.
ii. How do bacteria evade other immunological responses (e.g., antibody activity)?
c.
Toxin production
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Compare and contrast bacterial exotoxins and endotoxins.
• For exotoxins, what are A+B toxins, superantigens, and toxoids?
• For endotoxins, what are the roles of Lipid A and O polysaccharide?
Differentiate between a communicable and a noncommunicable disease.
Categorize diseases according to frequency: sporadic, endemic, epidemic, pandemic.
Define herd immunity.
Describe pathogen level, immune activity, and symptoms during each disease phase
(incubation, prodromal, illness, decline, convalescence).
Explain and recognize examples of disease transmission.
Define nosocomial infections and explain their importance.
List several methods of disease transmission in hospitals.
Explain how nosocomial infections can be prevented.
List five probable reasons for emerging infectious diseases. Name an example for each.