Hate cleaning up the lawn after your pet? Then you might be putting your entire family at risk of acquiring intestinal worms. Roundworms are often found in dog feces and can easily migrate into whichever patch of lawn Scout prefers to do his business. The danger kicks in when your kid picks up a football that's come into contact with the infected soil, then touches his mouth with his hands. The roundworms travel to his intestines, lay their eggs, and spread like wildfire, leading to symptoms ranging from breathing trouble to weight loss and diarrhea. What's worse is that roundworms can cause ocular larva migrans, which occur when worm larvae attack the retina, leading to blindness. A study conducted in a pediatric hospital in the 1970s found that 37 percent of the children admitted with retinal disease tested positive for the larva.