Correct Response: A. Of the three sexually transmitted diseases reported to the Center for Disease Control in 2014, chlamydia was by far the most common. It can be dangerous because the initial infection goes undetected in most of the women and about half of the men who contract the disease. If untreated, chlamydia can cause complications such as pelvic inflammatory disease and infertility in women and infections of the urethra and epididymis in men. Although untreated syphilis (B) can progress to a tertiary stage that can lead to heart problems, blindness, and dementia, it is currently much less prevalent in the United States than chlamydia, and also easier to detect at earlier stages. Untreated gonorrhea (C) can cause some of the same complications as untreated chlamydia. However, it is currently less common in the United States than chlamydia. Herpes simplex (D) is also a very common sexually transmitted infection in the United States and there is currently no cure. However, herpes does not usually cause the severe health complications that many other sexually transmitted infections cause.
