Ascariasis is an intestinal infection caused by a parasitic roundworm. Roundworms are typically quite large, measuring upto 18cm (7 inches) in length and are found in large numbers. When a dog's body becomes infected with roundworms, they can cause abdominal swelling (distention), colic, gastrointestinal issues and even intestinal rupture.
There are two species that commonly infect dogs: Toxocara canis and Toxascaris leonina. Adult roundworms live in the stomach and intestines and can grow to 7 inches (18 cm) long. A female may lay 200,000 eggs in a day. The eggs are protected by a hard shell. They are extremely hardy and can live for months or years in the soil.
Common symptoms of ascariasis are:
Poor nursing (in females)
Coughing (caused when the roundworm larvae have migrated into the dog's lungs)