This is a parasite of the stomach of ruminants and is a serious problem in cattle and sheep raising operations. It is often called the "barber-pole worm", because it feeds on blood and the red intestine and white ovaries of the female spiral in a manner resembling a barber-shop sign (if you are old enough to remember those). Adults are 20-30 mm long. Heavy infections can kill a host, but if they survive an immunity will develop. Newly-arrived larvae developing in the mucosa of the intestine stimulate an immune attack on the adults, which live in the lumen but are exposed to components of the immune system because they suck blood. Heavy infections, with thousands of worms per host, are common. Pasture can become heavily contaminated with eggs and larvae, and the infective third-stage larvae can survive desiccation for extended periods because they retain the cuticle of the second stage.