1. Larvae in muscle ........ Trichinella sp.
2. Ova in feces .......... Go to: 4 & 5
3. Adult worms seen in feces .......... Go to: 12 & 13

4. Ova with bipolar plugs ........ Trichuris suis
5. Ova without bipolar plugs ........ Go to: 6 & 7

6. Ova Embryonated or Larvated ........ Go to: 8 & 9
7. Ova NOT Embryonated or Larvated ........ Go to: 10 & 11

8. Ova larvated, round to oval with a slightly rough shell ........ Metastrongylus sp.
9. Ova embryonated, short oval to ellipsoid with smooth shell ........ Strongyloides ransomi

10. Ova round or oval with a rough coat around the shell and a single-cell stage ........ Ascaris suum
11. Ova ellipsoid, smooth shelled with morula stage ........ Strongyle-type ova (Oesophagostomum sp.)

12. Large nematode, body generally smooth. Anterior end is rounded with large lips ........ Ascaris suum
13. Large worm, body generally wrinkles. Anterior end possesses a rounded proboscis with hooks ........ Macracanthorhynchus ingens*
*Note: Macracanthorhynchus ingens is an Acanthocephalan (thorny-headed worm ) NOT a Nematode