The nematelminths (from Greek nematodes: 'filament', and helmin: 'worms') are worms of cylindrical body, tapered at the extremities.
Many species are of free life and live in aquatic environment or terrestrial; others are plant and animal parasites, including humans. There are over 10,000 species of this type of worms cataloged, but calculations indicate the existence of many other species, still unknown.
Unlike flatworms, nematelmints have complete digestive tract with mouth and anus. They usually have separate sexes, and the differences between male and female can be quite clear, as in the case of major human parasites.
In general the male is smaller than the female of the same age and its rear end is hooked. These animals are surrounded by a thin and delicate protective film, which is very smooth and resistant.
Roundworm (Ascaris lumbricoides)
Previous portion of Ancylostoma duodenaleshowing mouth with lacerating denticles.
Diseases Caused by Nematodes
Hookworms, roundworms, pinworms and branches are some examples of nematelmints that parasitize humans. Let's get to know them better.