Tina and her partner have been unable to conceive since marrying four years ago. Their doctor believes the infertility is a result of pelvic inflammatory disease from the most common STI. Which infection is most likely the cause?

After a recent checkup, Marcus learned from the doctor that he has contracted a protozoan STI. What is the most probable diagnosis?

Which stage of syphilis is marked by the appearance of a painless ulcer at the site of infection?

Maria, age 42, has recently been diagnosed with cervical cancer. Her doctor explains that it is likely connected to a sexually transmitted infection she contracted in her twenties. Which infection is most strongly associated with cervical cancer?

Which of the following vaginal infections is the result of an overgrowth of the yeast, which is usually present in low numbers?