Equis ISSN 2398-2977
Infective nematode larvae - free living nematodes: key for differentiation
Contributor(s): Sheelagh Lloyd
Key for differentiation of infective nematode larvae and free living nematodes from horse feces
- Without protective sheath → 2.
- With protective sheath → 3.
- Rhabditiform esophagus (dilated posteriorly into a bulb) = Free living nematode .
- Not a rhabditiform esophagus. Esophagus is filariform and is nearly half the length of the body = Strongyloides westeri .
- Gut comprising 8 cells = Cyathostomins ( Cyathostomum, Cylicocyclus, Cylicodontophorus, Cylicostephanus).
- Gut comprising 12 cells, button on tail = Gyalocephalus* .
- Gut comprising 16 cells → 4.
- Gut comprising >16 cells → 7.
- Without long sheath tail = Trichostrongylus axei .
- With sheath tail → 5.
- Very large larva with large, well defined, triangular cells = Oesophagodontus* .
- Not large triangular cells → 6.
- Medium length larva with clearly defined slightly rectangular cells, sheath without long tail = A cyathostomin Poteriostomum.
- Very long thin larva, ill-defined cells that are slightly rectangular. Small tri-lobed process on larval tail = Strongylus equinus.
- Gut comprising 18-20 cells → 8.
- Gut comprising 28-32 well defined rectangular cells, very long broad larva, short esophagus = Strongylus vulgaris .
- Cells well defined and regular, broad larva of medium length = Triodontophorus.
- Cells elongated and ill-defined, small thin larva, very blunt tail = Strongylus edentatus.
* Related to Triodontophorusspp Triodontophorus spp .