Structure of the male whipworm Trichuris trichiura, a nematode parasite of humans, computer illustration. The front of the worm (upper left) is narrow and pointed like a hair or whip. The rear is five or six times wider. Adult worms live in the intestine with the front end buried in the intestine wall. The worms can live for several years, usually without causing much harm to the host. When the infestation is severe, heavy diarrhoea, dysentery and anaemia can result. Worms intestine is coloured dark red, testis, vas deferens and ejaculatory duct are blue, nerve ring is purple. Non-labelled image.