The whipworm is the parasitic roundworm Trichuris trichiura — named for its whip-like shape, with a thin thread-like head end and a thicker handle-like tail. Adult worms embed their thin ends in the wall of the large intestine, where they feed on tissue fluids. Infection, called trichuriasis, comes from swallowing eggs in soil contaminated with human faeces. Light infections are silent; heavy burdens cause bloody diarrhoea, anaemia, and in children stunted growth. The eggs are extraordinarily hardy, surviving years in soil, which is why the disease persists where sanitation is poor. Treatment with antiparasitic drugs clears the worms, but only clean water, latrines, and hygiene break transmission.