This unpleasant material very often contains a parasitic roundworm, Toxocara Canis, which can cause blindness in humans.
The unseen eggs remain where dogs carrying the toxocara roundworm have defecated, long after the feces have disappeared.
Toxocara canis is the common roundworm of dogs, which is occasionally found in humans.
This is caused by a parasitic roundworm in the fox, toxocara canis, which can cause blindness in young children.
Toxocara cati is a white roundworm which most frequently infects young kittens, being passed via the mother's milk.