MICROBIOLOGY
ASSESSMENT #1
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Microbiology Assessment #1 – Virology:
1. A 22-year-old female presents to the physician with a painful vesicular eruption on her left
labium majus. She describes the pain as burning and stinging. She has a fever of 101F and left-sided
inguinal lymphadenopathy. Which of the following best describes the viral etiology?
A) DNA; enveloped; linear
B) DNA; enveloped; circular
C) DNA; non-enveloped; linear
D) DNA; non-enveloped; circular
E) RNA; enveloped; linear
F) RNA; enveloped; circular
G) RNA; non-enveloped; linear
H) RNA; non-enveloped; circular
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The answer is A.
This patient has an acute genital herpes infection.
This may be due to either HSV1 or HSV2. The literature has in the past supported a propensity for
HSV1 to cause herpes labialis (oral herpes) and HSV2 genital herpes, but the relationship is not
absolute and considerable overlap exists.1, 2, 3
Primary herpes infection
• Primary (first-time) infection often presents more severe than subsequent flareups, and is
frequently accompanied by fever and regional adenopathy.4
• Systemic symptoms, including headache, fever, myalgia, and backache occur in about 70% of
women and 40% of men.4, 5
The herpesviridae are double-stranded linear, enveloped, DNA viruses.6
This is in contrast to hepatitis B, which is a double-stranded circular, enveloped, DNA virus.7
The USMLE really likes this distinguishing structural detail between herpesviridae and
hepatitis B.
Bottom line: On your USMLE: Herpes is “DNA, enveloped, linear.” Hepatitis B is “DNA,
enveloped, circular.”
1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2564733/
2) https://www.ncbi.nlm.nih.gov/pubmed/62191/
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3) https://www.ncbi.nlm.nih.gov/pubmed/204741/
4) https://www.ncbi.nlm.nih.gov/books/NBK47449/
5) https://www.ncbi.nlm.nih.gov/pubmed/6344712
6) https://www.ncbi.nlm.nih.gov/pubmed/28528442
7) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3940099/