Table 1.
Selection of Human and Livestock Helminth Infections and Life Cycle Stages with Potential to Be Studied Using Organoids
| Organ | Helminth | Host | Life cycle stage relevant to organoid models |
|---|---|---|---|
| Stomach (abomasum) | Haemonchus contortus (barber's pole worm) | Sheep | L3 larvae invade epithelium of abomasum and mature to adults that remain attached |
| Small intestine | Ascaris lumbricoides; A. suum (roundworm) | Human; pig | L3 larvae hatch from ingested eggs, invade epithelium, L4 larvae/adults in lumen |
| Toxocara canis, T. cati (roundworm) | Human, dog, cat, rodents, rabbit, birds | L2 larvae hatch from ingested eggs, invade epithelium, L3/L4/ L5 and adults in lumen | |
| Heligmosomoides polygyrus | Mouse | Ingested L3 larvae invade epithelium and submucosa; re-emerge as adults into lumen | |
| Trichinella spiralis (pork worm) | Human, pig, mouse | L1 larvae invade epithelium and mature to adults | |
| Necator americanus, Ancylostoma duodenale (hookworms); Nippostrongylus brasiliensis | Human; mouse, rat | L4 larvae/adult worms in lumen (L3 enter through skin) | |
| Strongyloides stercoralis (thread worm); S. venezuelensis, S. ratti | Human, dog; mouse, rat | L4 larvae/adult worms in lumen (L3 enter through skin) | |
| Taenia saginata, T. solium (tapeworms); T. taeniaeformis, T. crassiceps | Human, pig, ruminants; mouse, rat | Ingested larvae (cysticerci) attach to epithelium, grow to adults | |
| Echinococcus granulosus, E. multilocularis (tapeworms) | Human, dog, cat, cattle, horse, sheep, pig, rodents | Eggs ingested by the first host hatch releasing oncospheres (larvae) that penetrate the epithelium and submucosa. Cysts and protoscolices that are ingested by a second host attach to epithelium and develop into adults |
|
| Fasciola hepatica, F. gigantica (liver fluke) | Human, sheep, cattle, mouse | Newly excisted juvenile (larvae) penetrate the intestinal wall of the duodenum into peritoneal cavity | |
| Small and large intestine | Schistosoma mansoni, S. japonicum (blood fluke) | Human, mouse | Adults in mesenteric veins produce eggs which transit intestinal wall to lumen |
| Large intestine | Trichuris trichiura; T. muris; T. suis (whipworm) | Human; mouse; pig | L1 larvae invade caecal/large intestinal epithelium and mature to adults |
| Skin |
N. americanus, A. duodenale; N. brasiliensis |
Human; mouse, rat | Free-living L3 larvae penetrate unbroken skin |
| S. stercoralis; S. venezuelensis, S. ratti | Human, dog; mouse, rat | Free-living L3 larvae penetrate unbroken skin | |
|
S. mansoni, S. haematobium, S. japonicum |
Human, mouse | Free-swimming cercariae in freshwater penetrate unbroken skin | |
| Lung | T. canis, T. cati | Human, dog, cat, cattle, horse, sheep, pig, rodents | L2/L3 larvae transit lung where may encapsulate or migrate through trachea and oesophagus to gut |
|
N. americanus, A. duodenale; N. brasiliensis; Ascaris spp |
Human; mouse, rat; pig | Developing L3/L4 stages transit lung, migrate through trachea and oesophagus to gut | |
| S. stercoralis; S. venezuelensis, S. ratti | Human, dog; mouse, rat | L3 larvae transit lung, migrate through trachea and oesophagus to gut | |
|
S. mansoni, S. haematobium, S. japonicum |
Human, mouse | Schistosomulae (larvae) develop prior to migration to vascular niche | |
| E. granulosus | Human, dog, cat, cattle, horse, sheep, pig, rodents | Oncospheres (larvae) circulate to the lungs where they develop into cysts and protoscolisces | |
| Liver | T. canis, T. cati | Human, dog, cat, cattle, horse, sheep, pig, rodents | L2 larvae transit liver where may encapsulate or migrate to the lung |
| S. mansoni, S. japonicum | Human, mouse | Eggs frequently trapped in liver, pathogenic | |
| E. granulosus, E. multilocularis | Human, dog, cat, cattle, horse, sheep, pig, rodents | Oncospheres (larvae) circulate to the liver where they develop into cysts and protoscolisces | |
| F. hepatica, F. gigantica | Human, sheep, cattle, mouse | Migrating juvenile and adults | |
| Brain | T. solium, Mesocestoides corti | Human, mouse | Cysts form in brain |
| Bladder | S. haematobium | Human, mouse | Eggs from adults breach barrier to reach urinary tract |
| Lymphatics/blood vessels | Brugia malayi (and other lymphatic filariae) | Human | Adults live in lymphatic system, microfilariae in peripheral blood |