Hydatid disease is most frequently associated with sheep herding, but humans should wear gloves when handling scat, and avoid allowing their pets to lick them on the mouth, in order to decrease the possibility of becoming infected by a tapeworm-infested dog or cat. Yet, even if the parasite does find a way into a human host, infection does not always lead to serious health effects. Cysts may exist in humans for many years before symptoms become apparent and, occasionally, there are never any signs of illness. The cysts can become extremely problematic, however, if they grow to large sizes, develop on the brain, or rupture.