A 32-year-old gender nonbinary person is evaluated for a 3-day history of abdominal cramping and non-bloody diarrhea. They deny fever, chills, urethral symptoms, anorectal pain, anal discharge, and other systemic symptoms. They engage in receptive anal intercourse as well as anilingus (oral-anal contact) and report having four cisgender male sex partners in the past 6 months. They rarely use condoms. They tested negative for HIV approximately 4 months prior. On further discussion, they report two of their sex partners have recently had similar symptoms.