Signs of Common Dog Hookworm

Hookworms are intestinal parasites of dogs and cats, especially young animals with less mature immune systems. Hookworms are some of the most common parasites veterinarians find infecting dogs, and they attach themselves to an animal's intestinal wall with vicious-looking mouths filled with sharp tooth-like cutting plates. Hookworms feed on blood they suck through the bite. Hookworms are about a half-inch long and very thin; 300 hookworms can suck 10 percent of a host's blood every day. Each female hookworm can lay more than 20,000 eggs per day.

  1. Species

    • The hookworm species that infect dogs are Uncinaria stenocephala, Ancylostoma caninum and Ancylostoma braziliense. Generally, U. stenocephala is more prevalent in colder climates and A. braziliense appears more often in semi-tropical and warmer regions. Symptoms of and treatment for all species of hookworm are the same.

    Infection

    • A dog may become infected with hookworms by eating eggs or when hookworm larvae burrow into the dog's skin. The larvae can survive in soil or on damp vegetation as they wait to contact a victim. Less frequently, hookworms migrate from the body of a pregnant animal directly into the fetuses she carries. The parasites may also be transmitted through the milk of nursing mothers. Hookworms can spread among a group of dogs that spend time together, and can become a problem in kennels.

    Symptoms and Signs

    • Because hookworms suck their host's blood, they can cause anemia. Anemic dogs will weaken and have pale gums. A dog may also exhibit gastrointestinal signs. Occasionally, the animal will have black, tarry stools, and vomiting and diarrhea may also be signs of hookworm. An infected dog's coat may be dull and dry. Hookworms may stunt a puppy's growth, and dogs may also lose weight or act depressed. In severe cases of hookworm, larvae may invade the lungs, leading to coughing and pneumonia. If left untreated, hookworm infection can kill a dog. Because the signs of hookworm are so general, only the presence of eggs in the feces is diagnostic for infection.