Dear Diane..

The pictures are not clear. You should take a picture of the total body of the parasite. Then list in your question the scientific name of the host, the sight of infection and the habitat of the host. if you can prepare a permanent slides for the parasites, that is better. Good luck

your pictures are not clear , but i think it belong to nematoda

I think Nematod. But is not clear

Were you able to identify any eggs?

First of all identify by key. Another method is fecal culture, for example Harda and Murray culture for carnivores, which ultimately identify the cultured infant parasite and diagnose with their posterior end and tail.

@Alan Hecht, no eggs in this sample. But in others there were Toxoxara sp, Trichuris sp, Dipyllidium caninum, Isospora sp., strongyloides sp

Yes,I'm agree with you Dr Alan hecht

The pictures are blurred, but it should be a nematod