The Trichomonas vaginalis parasite exists all over the world, according to BioMed Central. It is a pear-shaped or amoeba-like organism about 10 to 20 nanometers long and 2 to 14 nanometers wide. It has five flagella, or whip-like extensions, and a tail-like axostyle to help it move.
Trichomonas vaginalis is anaerobic, which means it can survive without oxygen, explains BioMed Central. Eaten by white blood cells called macrophages, its only known host is the human, and it feeds on vaginal epithelial cells and red blood cells. It also consumes bacteria. The parasite causes a disease called vaginitis. It is more prevalent in women, but it can also affect men.