Ch. 24 - Pathogenic DNA Viruses

Bauman - Microbiology with Diseases by Taxonomy 6th Edition

Bauman6th EditionMicrobiology with Diseases by TaxonomyISBN: 9780134832302Not the one you use?Change textbook

Bauman 6th Edition

Ch. 24 - Pathogenic DNA Viruses

Problem 4

Chapter 24, Problem 4

Which of the following statements is true concerning variola major?
a. It carries a mortality rate of less than 1%.
b. It affects internal organs before appearing on the skin.
c. The causative virus has been totally eradicated from Earth.
d. The skin lesions it causes are smooth, waxy, tumorlike nodules on the face.

Verified step by step guidance

Step 1: Understand what variola major is. Variola major is the more severe form of the virus that causes smallpox, a serious infectious disease.

Step 2: Review the mortality rate associated with variola major. Historically, variola major had a high mortality rate, often much greater than 1%, so statement (a) can be evaluated based on this fact.

Step 3: Consider the pathogenesis of variola major. The virus typically affects internal organs early in infection before the characteristic skin rash appears, which relates to statement (b).

Step 4: Reflect on the current status of the variola virus. Smallpox, caused by variola virus, was declared eradicated worldwide by the WHO in 1980, which is relevant to statement (c).

Step 5: Analyze the description of the skin lesions caused by variola major. The lesions are typically pustular and not described as smooth, waxy, or tumorlike nodules, which helps assess statement (d).

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Key Concepts

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

Variola Major and Smallpox

Variola major is the virus responsible for the severe form of smallpox, characterized by a high mortality rate historically ranging from 20% to 30%. It causes a systemic infection with distinctive skin lesions and was a major cause of death before eradication efforts.

Pathogenesis and Clinical Presentation of Variola Major

Variola major initially infects internal organs and the bloodstream before causing the characteristic skin rash. The lesions progress through stages from macules to papules, vesicles, pustules, and finally scabs, typically appearing as firm, deep-seated pustules rather than smooth or waxy nodules.

Eradication of Smallpox Virus

The variola virus, which causes smallpox, was declared eradicated in 1980 following a global vaccination campaign led by the WHO. No naturally occurring cases exist today, and the virus is only kept in secure laboratories for research purposes.

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What observation led scientists to understand the relationship between shingles and chickenpox?

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You have been given a large grant to do postgraduate research on live smallpox viruses. Where in the world would you find samples?

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Textbook Question

What was the difference in the effects of variola major and variola minor?

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Textbook Question

The initial flat, red skin lesions of poxviruses are called____.

a. macules

b. papules

c. pustules

d. pocks

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Most of the world’s population in less developed and developing countries have been infected with EBV human herpesvirus 4 by age one and show no ill effects, even where medical care is poor. In contrast, individuals in industrialized countries are ordinarily infected after puberty, and these older patients tend to have more severe reactions to infection despite better overall health and access to medical care. Explain this apparent paradox.

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