In countries like India, these constitute an important public health problem because infestation by hookworms is the cause of anemia in a significant number of children A wide variety of worms infest humans, these range from half-inch pinworms to tape worms as long as 30 feet. The more important among them are the pinworms, the roundworms, and the hookworms. Any worm infestation can lead to respiratory or cardiovascular complications. These are very small worms, the size of about 2-4 mm, white in color and generally seen in clumps. It is characterized by the intense itching it produces in the anal area.
Pinworms live in people's lower intestinal tracts.
The female worm leaves the anus to deposit eggs in the anal area at night and induces severe itching. The consequent scratching transfers the eggs to the host's fingers. If inadvertently eaten, the eggs reach the intestines - hatch in the intestines and thus the cycle continues. It lives in the small intestine, lays enormous quantities of eggs that are excreted in the feces. The eggs remain viable for a long time in the soil and can enter the body in unwashed or raw food.