Large and small roundworms - generalities

27.5 Large and small roundworms - generalities Large and small roundworms irritate and damage the lining of the stomach and the intestine, resulting in poor food absorption and growth. Some roundworms damage the liver and lungs as their larvae migrate throughout the body. Large roundworms may block the intestines. Lungworms (a type of small roundworm) irritates the animal’s airways, cause coughing, increased risk of lung infection, and a general unhealthy appearance. All of these effects are especially serious in young animals.