Trichomoniasis (or “trich”) is a very common sexually transmitted disease (STD). It is caused by infection with a protozoan parasite called Trichomonas vaginalis. Although symptoms of the disease vary, most people who have the parasite cannot tell they are infected. How common is trichomoniasis?
https://www.cdc.gov/std/trichomonas/STDFact-Trichomoniasis.htm