A 24-year-old woman is diagnosed with human papillomavirus (HPV) after having her annual ...

C
HPV types 16 and 18 can cause cervical and penile cancer.

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C
Most of the organisms discussed in Chapter 22 exist in the environment. As environmental or-ganisms, these bacteria are rarely encountered in human specimens or infections. When they are encountered, they are found on contaminated medical devices or are isolated from patients who are immunocompromised or otherwise debilitated.

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D
HBsAg is the most reliable marker for the identification of an HBV infection. The antigen be-comes evident in the patient's serum weeks before any biochemical evidence associated with liver damage is observed. (Biochemical liver assays may show only minimal elevation.) HBsAg remains in the serum during the acute and chronic stages of HBV. The presence of HBsAg 6 months after acute infection indicates that the patient is a chronic carrier. Immunoglobulin M (IgM) anti-HBcAb to hepatitis B core antigen (HBcAg) appears early in the course of disease during the acute infection. Anti-HBsAg indicates the patient is in convalescence and has devel-oped immunity. Finally, the presence of the extracellular form of HBcAg (HBeAg) indicates high infectivity and a chronic carrier state.

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B
Dengue virus is the most prevalent arbovirus in the world, with more than 100 million people infected annually. The virus is endemic in Latin America, Puerto Rico, and Mexico. The majority (>90) of the cases reported in the United States are related to travel. Humans are the main reservoir for this virus, with person-to-person transmission occurring via a mosquito vector.

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B
Chancroid is the sexually transmitted disease caused by H. ducreyi. Although small outbreaks of this disease have occurred in the United States, this disease is more commonly recognized among socioeconomically disadvantaged populations that inhabit tropical environments.