I have seen some worm in feces images which looked similar, maybe flukes. It is sometimes amost impossible to make an id of worms because they may have been killed and partly digested or damaged on their way out of the gut. If you need to know if these are parasites then get a parasite collection bottle with preservative and send to a lab. Or get one of the molecular exams of stools which ids parasites and other organisms in the gut by their DNA, Metametrix Lab is one.