Table 1.
Major helminth parasites including species implicated in modulating colitis
| Phylum | Species | Notes |
|---|---|---|
| Cestodes (Tapeworms) | Echinococcus granulosus | Causes hydatid cysts of the liver following ingestion of eggs from dogs. |
| Hymenolepis diminuta | Small tapeworm of rats; other members of genus can infect humans. | |
| Taenia saginata, T. solium | Human tapeworms, transmitted through undercooked beef or pork; can cause cysticercosis and neurocysticercosis. | |
| Nematodes (Roundworms) | Ancylostoma caninum, A. ceylanicum, A. duodenale | Hookworms of dogs and humans, larvae in soil penetrate skin and home to gut via the lungs. |
| Anisakis simplex | Parasite of marine mammals; larvae in fish can infect humans if eaten raw. | |
| Ascaris lumbricoides | Common roundworm of human; infects ~800 million people; direct fecal-oral transmission through eggs in environment. | |
| Brugia malayi | Lymphatic filarial parasite, mosquito-borne, causes elephantiasis | |
| Heligmosomoides polygyrus | Mouse intestinal nematode related to hookworm, widely used model system. | |
| Necator americanus | Human hookworm; together with A. duodenale infects ~600 million people. | |
| Strongyloides stercoralis | Threadworm, infects intestinal tract and causes strongyloidiasis. Can autoinfect the host, hence lifelong infection. | |
| Toxascaris leonina | Large roundworm of cats and canids, closely related to Ascaris in humans. | |
| Trichinella spiralis | Pork worm, contracted from undercooked meat, larvae invade muscle cells of the host. | |
| Trichuris trichiura | Whipworm in large intestine; infects ~600 million people. Related species from pigs (T. suis) used in helminth therapy. | |
| Wuchereria bancrofti | Lymphatic filarial parasite, mosquito-borne, causes elephantiasis. | |
| Trematodes (Flukes) | Clonorchis sinensis | Liver fluke prevalent in Asia, can cause cholangiocarcinoma. |
| Schistosoma japonicum | Causes schistosomiasis japonica, hepatosplenic disease; transmitted through intermediate snail host releasing water-borne invasive cercarial larvae. | |
| Schistosoma mansoni | Widespread cause of schistosomiasis, together with S. hematobium and S. japonicum, afflicting ~200 million people. |