This is a study developed by researchers from the Universidad Peruana Cayetano Heredia, the Universidad Mayor de San Marcos and other local and foreign institutions. Researchers are performing this research in human beings and animals, in order to determine the best way to understand and eliminate a parasite called Echinococcus granulosus (tapeworm). The parasite grows and develops in the dogs´ bowel. The tapeworm produces eggs which are eliminated among the feces and remain in the environment. Individuals may accidentally ingest the eggs through contaminated food or drinks and develop a disease called cystic hydatid disease. This disease mainly affects the human lungs and liver. The parasite grows in the shape of a water bag and it can jeopardize human life. It also affects sheep, goats, llamas and alpacas. The study will enroll almost 840 volunteers who are older than 5 years of age. It will last about 3 years.