<unk>  is a highly prevalent single-celled parasite that infects the gastrointestinal tract of humans and animals.  Many different types of<unk>  exist, and they can infect humans, farm animals, birds, rodents, amphibians, reptiles, fish, and even cockroaches.
Blastocystis
Cryptosporidium
Echinococcus
Ehrlichia
Cryptosporidium hominis
Acanthamoeba
Plasmodium
Oesophagostomum