Largest parasitic nematode

Also known as roundworms, the largest parasitic species of nematode in the world is Placentonema gigantissimus, which can reach a length of 7.62 m (25 ft) and inhabits the placenta of sperm whales. The largest parasitic nematode of humans is probably the Guinea worm or 'fiery serpent of the Israelites' Dracunculus medinensis, a subcutaneous species whose females measure up to 1.21 m (4 ft) long. The nematode (roundworm) species range in size from microscopic to about 10 cm (4 in) long with the exception of Placentonema gigantissima. This 8-m-long nematode is said to have 32 ovaries. Roundworms are cylindrical shaped animals with simple bodies consisting of an interior gut and a muscular outer wall, separated by a fluid-filled cavity called a pseudocoel.The outer wall secretes an elastic cuticle that is molted four times during the animal lifetime. Dracunculus medinensis causes the disease known as dracunculiasis, and the parasite is often referred to as the guinea worm or fiery serpent. This parasite and the disease that it causes have been mentioned in the ancient writings of Greek, Roman, and Arabian scholars. It is commonly found in Asia, the Middle East, Arabia, and northern and equatorial Africa.