Final answer:
Pinworms, associated with the condition called enterobiasis, are parasites that infect the human intestine, primarily affecting children. Transmission occurs through the fecal-oral route, and the main symptoms include itching around the anus and sleep disturbances.
Step-by-step explanation:
Pinworms, known scientifically as Enterobius vermicularis, are classified as parasites. These tiny nematodes (helminths) are the most common intestinal worms in humans, particularly in children in the United States. They are multicellular organisms that can generally be seen without a microscope, though their eggs and larvae are microscopic. Pinworm infections are typically transmitted via the fecal-oral route, where eggs are ingested and hatch in the small intestine. Adult worms primarily reside in the colon, and females lay eggs around the perianal area at night, causing itching and facilitating the spread of the infection.