Final answer:
Trichomoniasis is a common sexually transmitted infection (STI) caused by the protozoan parasite Trichomonas vaginalis, which is transmitted sexually.
Step-by-step explanation:
Trichomoniasis is a common STI caused by the protozoan parasite Trichomonas vaginalis. Sexual route is the method of transmission of trichomoniasis. It is the most common nonviral STI and can cause a range of symptoms including urinary discomfort, irritation, and discharge. This infection also increases the risk of transmitting or acquiring HIV and is associated with pregnancy complications, such as preterm birth.