Then she stood there staring in amazement at the fish's insides. The little girl, Judy Sakanari, grew up to be a scientist at the University of California at San Francisco where she studies parasites that are found in fish. A parasite is an animal that lives on or inside another animal known as its host, and is dependent on the host for its food to survive. But now she regularly examines fish for parasites. One parasite she studies is a worm about an inch long that is found in fish.
Many animals have parasites.
Dogs and cats can have parasites like ticks and fleas on their skin and roundworms and tapeworms inside. Humans can also get infected with parasites. One of the larger questions I am interested in answering is how parasites cause disease in humans. Unlike the relationship between a parasite and its host, some relationships among animals are mutually beneficial. That means each needs the other, but each also helps the other.