WBR0465

Author	[[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Yazan Daaboul, M.D. and Alison Leibowitz [1])]]
Exam Type	ExamType::USMLE Step 1
Main Category	MainCategory::Microbiology
Sub Category	SubCategory::Genitourinary
Prompt	[[Prompt::A 60-year-old woman presents to the physician’s office with post-coital bleeding. A cervical smear is performed, and the patient's pathological findings are shown in the image below. The physician then explains to the patient that her condition is most likely caused by a sexually transmitted virus. Which of the following characteristics best describes the virus responsible for this patient's condition? ]]
Answer A	AnswerA::Double-stranded, non-enveloped DNA virus
Answer A Explanation	AnswerAExp::The human papilloma virus (HPV) is a double-stranded, non-enveloped DNA virus.
Answer B	AnswerB::Double-stranded, enveloped DNA virus
Answer B Explanation	AnswerBExp::Herpesviruses, adenoviruses, and poxviruses are double-stranded, enveloped DNA viruses.
Answer C	AnswerC::Single-stranded, non-enveloped DNA virus
Answer C Explanation	AnswerCExp::Parvoviruses are single-stranded, non-enveloped DNA viruses.
Answer D	AnswerD::Single-stranded, enveloped RNA virus.
Answer D Explanation	AnswerDExp::flaviviruses, togaviruses, retroviruses, coronaviruses, orthomyxoviruses, paramyxoviruses, rhabdoviruses, filoviruses, arenaviruses, bunyaviruses, and delta virus are all examples of single-stranded, enveloped RNA viruses.
Answer E	AnswerE::Double-stranded, non-enveloped RNA virus
Answer E Explanation	AnswerEExp::Reoviruses are double-stranded, non-enveloped RNA viruses.
Right Answer	RightAnswer::A
Explanation	[[Explanation::The patient presents with an abnormal pap-smear that displays the presence of koilocytes, which are abnormal cells infected by the human papilloma virus (HPV). The image illustrated above depicts a normal cervical cell on the left, and a koilocyte on the right. Characteristically, koilocytes contain large nuclei with a perinuclear halo. HPV is a sexually transmitted, double-stranded, non-enveloped DNA virus. Among the most significant HPV types are HPV types 16, 18, 31, 33, and 45, which predispose to the development of cervical cancer. In contrast, HPV types 6, 11, 42, 43, and 44 frequently result in genital warts and HPV types 1 and 4 are associated with development of skin warts. Educational Objective: Koilocytes, with characteristic enlarged nuclei with perinuclear halos, are cells infected with HPV. HPV is a sexually transmitted virus manifesting in over 100 forms, some of which predispose to cervical cancer and others to genital warts. References: First Aid 2014 page 158]]
Approved	Approved::Yes
Keyword	WBRKeyword::Koilocytes, WBRKeyword::Pap smear, WBRKeyword::Papsmear, WBRKeyword::Cervical smear, WBRKeyword::DNA virus, WBRKeyword::HPV, WBRKeyword::Papilloma virus, WBRKeyword::Papillomavirus
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