Worms
They have cutting plates and teeth in their mouth. Hookworms are able to infect both dogs and cats, with cat infections rare in the UK. The hookworm lives in the small intestine, attaching to the intestinal wall and feeding on blood.
Hookworm eggs are in the environment, in the faeces passed by infected dogs. Other animals are then infected by ingesting the eggs, either in the faeces, or when ingesting another host. The eggs will then develop into adult hookworm within the intestine. Larvae are also able to penetrate the skin, usually around the foot, causing infection.
Foxes can also be infected with fox hookworm, and so dogs can also be at risk of contracting this from fox faeces.
Symptoms of hookworm infection include diarrhoea, anaemia, anorexia and lethargy.