Early, immature forms of tapeworms can be present in some types of infected beef, pork, and fish. Cooking the fish and meat long enough will kill the tapeworms. Tapeworms are usually acquired when people eat meat or fish that has not been cooked enough. The tapeworms produce eggs in the intestines which then get passed out of the body in the feces (poop). If human feces wind up in the environment (due to poor sewage, for example) the tapeworm eggs may wind up in soil, grass, and water. When this happens, other animals, such as cows, dogs, pigs, and fish may consume the tapeworm eggs.
The tapeworms can then break out of the eggs when they are inside the animal's intestines. The first form of the tapeworm (known as a hexacanth) attaches itself to the wall of the intestine and continues to grow and develop. The tapeworm will develop into an adult when it is passed on to live in another organism. For example, the tapeworm can be in preadult form when it lives in a human and can develop into an adult form when it is passed on to a dog. From the above information, you can see that tapeworms can live in more than one animal at different points in their lives.
Another way that people acquire tapeworms is by touching feces that have tapeworm eggs in them and later putting their fingers in their mouths. Although it may seem like common sense not to do this, it can happen by accident.
Another way that people acquire tapeworms is by touching feces that have tapeworm eggs in them and later putting their fingers in their mouths. Although it may seem like common sense not to do this, it can happen by accident. I am not sure what is the largest. The site I have sent will show you what they look like.