White worms in a dog's stool can be a sign of a roundworm infestation, explains WebMD. The worms are a couple of inches long and are thin, resembling spaghetti noodles.
Roundworms live in and feed off the dog's intestines, states WebMD. Although not all dogs demonstrate any symptoms other than the appearance of the worms in the feces, some dogs exhibit other symptoms such as weakness and weight loss. Often, the infected dog gets a pot-belly, demonstrates signs of belly pain, and suffers from diarrhea and vomiting. An owner should consult a veterinarian immediately, as a roundworm infection can infect humans, especially children, resulting in neurological, heart and lung issues.
A dog with roundworm can be effectively treated with deworming drugs such as fenbendazole and moxidectin, according to WebMD. A dog is usually given three doses of the drugs, spaced apart. The first dose kills the adult worms, and the subsequent doses kill any worms that were either eggs or too young to be affected by the first dose.
A dog usually contracts roundworms through its mother or the environment, says WebMD. Dogs that eat small animals or feces contaminated with the parasite swallow the eggs. Once the eggs hatch into larvae, they spread to the liver and intestines.