Dog pests are parasites that can cause discomfort and disease to our canine companions. Ticks are small, blood-sucking arachnids that attach themselves to the skin of a dog and feed on their blood. LICE are tiny insects that live in the fur of a dog and feed on their skin and blood. Fleas are small, wingless insects that jump from host to host and feed on the blood of a dog. All three of these pests can be difficult to eradicate and can cause serious health problems for dogs if left untreated.