They may become anemic due to the parasites' blood sucking. Veterinarians diagnose strongyle infection from microscopic observation of eggs in the feces. Blood tests are often used to assess the seriousness of an infection. Frequent deworming treatments are recommended to reduce the risk of serious problems from these parasites and should be decided upon following consultation with your veterinarian. Colic, coughing, and diarrhea may also result from ascarid infection.
Foals acquire infective ascarid eggs from feces that other horses have passed.
Infective eggs, swallowed in contaminated hay or water, hatch in the intestinal tract. The young worms burrow through the intestinal wall, taking about a week to make their way to the lungs. From there the young worms travel up the trachea to the mouth, to be swallowed a second time. They mature in the intestine in two to three months, then lay eggs that are passed in the feces to start the cycle anew. Female ascarids can lay up to 200,000 eggs per day.