21. Principles of Disease

Compare pathogenicity with virulence.

Which of the following genera is the most infectious? <IMAGE>

If C. tetani is relatively sensitive to penicillin, why doesn’t penicillin cure tetanus?

Compare and contrast cat-scratch disease and toxoplasmosis.

Why is C. perfringens likely to grow in gangrenous wounds?

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DRAW IT Show the location of the following diseases: common cold, COVID-19, diphtheria, coccidioidomycosis, influenza, pneumonia, scarlet fever, tuberculosis, and whooping cough.

Compare and contrast mycoplasmal pneumonia and viral pneumonia.

Complete the following table.

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A patient has been diagnosed as having pneumonia. Is this sufficient information to begin treatment with antimicrobial agents? Briefly discuss why or why not.

List the causative agent, mode of transmission, and endemic area for the diseases histoplasmosis, coccidioidomycosis, blastomycosis, and Pneumocystis pneumonia.

A patient with nausea, vomiting, and diarrhea within 5 hours after eating most likely has

a. shigellosis.

b. cholera.

c. E. coli gastroenteritis.

d. salmonellosis.

e. staphylococcal food poisoning.

DRAW IT Diagram the pathway taken by E. coli to cause cystitis. Do the same for pyelonephritis. Diagram the pathway taken by N. gonorrhoeae to cause PID.

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How are urinary tract infections acquired?

Name one organism that causes pyelonephritis. What are the portals of entry for microbes that cause pyelonephritis?

Explain why E. coli is frequently implicated in cystitis in females.