Trichomonas infection, also known as trichomoniasis, is a sexually transmitted infection (STI) caused by the protozoan parasite Trichomonas vaginalis. It is one of the most common curable STIs and primarily affects the Can You Catch STDs From Sex Toys? Home STD Tests myLAB Box Trichomoniasis: Symptoms, Causes, Treatments, and Key Facts Trichomoniasis Why Routine STD STI Testing Is Important Scarlet SEX ED SUNDAY: Trichomoniasis Trichomoniasis (commonly known as 'trike' or 'trich') is an STI caused by a parasite that can cause inflammation and infection of the urethra, vagina, and cervix