#1 Tape Worms
If a tapeworm larva is eaten, it can grow into a full-blown adult that feeds off of the intestinal wall. This little guy can live in a human gut for nearly 30 years. They like to live in people’s intestines and are transferred from animals, mostly cows and pigs. This happens either through the consumption of infected meat or unwashed vegetables.
#2 Liver Flukes
Liver flukes are parasites that infect the bile ducts and liver. They are one of a number of flatworms that breed in freshwater snails. One way they can infect humans is through the consumption of freshwater fish that share the same environment.
#3 Hook Worms
Hookworms make an interesting journey through the human body. They enter through the feet and can sometimes leave itchy rashes at their entry point. They will travel along the bloodstream until they can enter the lungs. Once in the lungs, they irritate lung tissue enough that the infected host coughs them up into their mouth. If even a little bit of that bloody, wormy phlegm gets swallowed, the hookworm is happily in its desired home: the small intestine.
Pinworms are a parasite that can spread very easily. They are generally the most common parasitic infection in North America. They live on the human anus, so it takes just one scratch, and then anything that person touches can be covered with pinworm eggs. If someone swallows an egg, they become infected.