Pinworms are also called Enterobius vermicularis. They live in the human rectum and are a quarter of an inch long. When an individual sleeps, the female worms travel from the intestines through the anus and deposit eggs around the skin of the anus. This is why people experience itching during the night. It is said that excess saliva secretion stimulated by parasites causes stasis (the normal flow of a body liquid or intestinal content stops), which create the right environment for bacterial overgrowth during sleep.
Giardia is a widespread parasite that can be found in soil, food, water or surfaces contaminated with feces. The symptoms are abdominal discomfort with excessive gas and foul-smelling stool.
Trichomonas vaginalis is a one cell parasite that causes Trichomoniasis. The infection can be manifested in the urethra in man, and in the vagina in women. Trichomoniasis can produce in women a foul-smelling discharge, which may be green/yellow, and profuse or light, or white, and scant.