An intense inflammation occurs in the intestine as the eggs pass through it. Diarrhea, with mucous and often blood, results. Dogs lose their appetite and may become emaciated. The wall of the intestine may become very thickened. Cirrhosis of the liver can occur if the eggs are laid in its small veins and then enter the liver itself.
Diagnosis is made by finding the eggs in the feces.
Flotation methods are not effective for concentrating these eggs. Best results are obtained by smearing a small amount of feces and water on a microscope slide and examining it. The logical approach to prevention is keeping dogs out of the water. With hunting dogs, this is impossible. Keeping dogs out of the water in the morning when the infective forms emerge from the snails is not effective since these forms can live 24 hours - there will always be some present.