Internal parasites can live inside your cat and multiply so watch out for the warning signs of various bugs. Roundworms will cause loss of appetite, or a spaghetti-length worm found in faecal matter or in a pet's vomit. Other indicators include soft stools, mucus in the stool, vomiting or diarrhoea. Tapeworm scan be contracted from a flea. Worms appear as rice-like segments on the pet's anus or in its faecal matter.