View images of tapeworms Worm attaches to wall of intestine by specialized head segment called the scolex , with suckers or hooks that attach firmly to intestine. Majority of cases are asymptomatic. Many hosts only discover the infection by finding tapeworm segments in stool samples or finding motile proglottids emerging from the anus. Roundworms are members of the Nematode phylum. Nematodes are incredibly abundant in soil, water, and living in and on the surfaces of other organisms.
Some species are parasitic on humans.
View individual Ascaris worms . All inhabit the small bowel. Very common in warmer developing countries. Common with low standards of hygiene, poor sanitation. View life cycle of Ascarid worms Further Reading Visit the Atlas of Parasitology for extensive material on parasites Visit the Photographic list of parasites at Ohio State University.