Medicine Net explains that trichomoniasis is a parasite that thrives in warm and moist conditions. This parasite cannot live long outside of a host. Even if someone that has trichomoniasis sits on a toilet and leaves the parasite behind, it is extremely unlikely to live long enough to be a concern.
Trichomoniasis can be contracted by both men and women, although the symptoms of the disease may vary. Women typically have the more prevalent and frequent symptoms.