Concept Questions - Chapter 22
Take some time to write answers to these questions.
If you can answer them, you have a good grasp of the material!

1. Explain how true pathogens differ from opportunists in physiology, virulence, types of infection, and distribution.
Give examples of each.
Explain the adaptation and importance of thermal dimorphism.

2. Why are most fungi considered facultative parasites and fungal infections considered non-communicable?
Give examples of two communicable mycoses.

3. What factors are involved in the pathogenesis of fungi?
What parts of fungi are infectious?
What are the primary defenses of humans against fungi?

4. What is the role of skin testing in tracing fungal infections?
What causes cross-reactions?
For which groups is it most useful?

5. Give an overview of the major steps in fungal identification.
What is one advantage over bacterial identification?
How are in vitro and in vivo tests different?
Describe an immunodiffusion test; the histoplasmin test.
What biochemical and genetic tests can be conducted in identification?

6. What are the general principles involved in treating fungal diseases with drugs?
Why is amphotericin B so toxic?
Name some topical medications and their uses.

7. Differentiate between systemic, subcutaneous, cutaneous, and superficial infections.
What is the initial infection site in true pathogens?
What does it mean if an infection disseminates?

8. Briefly outline the life cycles of Histoplasma capsulatum, Coccidioides immitis, and Blastomyces dermatitidis.
In general, what is the source of each pathogen?
Is disease usually overt or subclinical?
To which organs do these pathogens disseminate?
What causes cutaneous disease? How are cutaneous diseases treated?

9. What are the most common subcutaneous infections?
Why are these organisms not more invasive?
Describe the life cycle of Sporothrix and the disease it causes.
How could one avoid it?

Differentiate between chromoblastomycosis and phaeohyphomycosis.

10. What are the dermatophytoses?

What is meant by the term keratophile?

What do the fungi actually feed upon?

To what do the terms ringworm and tinea refer?

What are the three main genera of dermatophytes, and what are their reservoirs?

11. What are the five major types of ringworm, their common names, symptoms, and epidemiology?

What conditions predispose an individual to these infections?

12. What is the difficulty in ridding the epidermal tissues of certain dermatophytes?
What is necessary in treatment?

13. Briefly describe three superficial mycoses.

14. What is the relationship of Candida albicans to humans?
What medical or other conditions can predispose a person to candidiasis?

Describe the principal infections of women, adults of both sexes, and neonates.
Why should women be screened for candidiasis?
What are the treatments for localized and systemic candidiasis?

If a woman tests positive for infection, besides treating her, what else should be done?

15. Describe the pathology of cryptococcosis.
What specimens could be used to diagnose it?
Which group of people is currently most vulnerable to this disease?
What makes the fungus somewhat unique?

16. Briefly list the major diseases caused by Aspergillus and zygomycetes.
Why are fungus balls not an infection?
Briefly outline the epidemiology and pathology of Pneumocystis carinii.

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