Hookworms get their name from their hook-like teeth. Hookworms are one of the most dangerous intestinal parasites of dogs and cats because they feed on blood. These parasites use their sharp teeth to attach to the interior lining of the host’s intestine where they can consume copious amounts of blood. A heavy infestation of hookworms in a puppy or kitten can cause severe blood-loss anemia, leading to death.

These worms may move from one site to another in the intestine, leaving bleeding ulcers at each previous bite wound.

Hookworms are very common in dogs and cats. One subspecies of hookworms, Ancylostoma caninum, crosses the mammary tissue of the dam and infects puppies as soon as they nurse.  Kittens are usually infected through the environment. Because they are so common, all puppies and kittens should be routinely dewormed early in life. Hookworms are very small and are very difficult to see with the naked eye. It is rare that a pet owner identifies these worms in the animal’s stool. They are more easily identified through laboratory testing.

There are several ways an animal can be infected with hookworms. Puppies are most often infected while nursing. The larval worm from the dam passes through the mammary gland and into the milk and is ingested by the baby. Puppies and kittens as well as adult animals can also be infected by ingesting the larva of the hookworm. Eggs are passed in the stool of infected animals, which then develop into infective larva in the environment. These larva may be ingested, but they also have the ability to invade the skin of pets (and humans) who come in contact with contaminated soil. The larva then migrate to the intestine where they complete their life cycle. Finally, dogs and cats can become infected if they eat another infected animal. Even 100% indoor pets are at risk, as some insects pests (e.g. cockroaches) can carry infective larva and may be eaten by the pet inside the home.

photoHookworms are a zoonotic disease, meaning people can also be infected.

Hookworms are a zoonotic disease, meaning people can also be infected. Infection most often occurs when the larva of the worm comes in contact with exposed skin when the person digs or walks barefoot through contaminated soil. Humans are not the normal host for these worms, but they can cause a severe skin irritation when the larva migrate through the skin. Thankfully, the hookworm cannot complete its life cycle in a person, and the larva will die within the skin after several weeks. Treatment by a physician can shorten the course of disease. In people, the disease is called Cutaneous Larva Migrans. Thorough hand-washing after outdoor activities and wearing shoes anywhere infected animals may have been will help prevent transmission.

The life cycle of a hookworm takes approximately three-four weeks to complete.

© Novartis Animal Health 2014

A diagnosis of hookworm infection is made by fecal floatation. Treatment is usually effective and straightforward. Treatment generally consists of a general dewormer and environmental cleaning. Indoors, the floor should be vacuumed and cleaned with an all-purpose cleaner. Litter boxes and bedding should be scrubbed and laundered. All animals in the house should be dewormed together to ensure all infected animals are treated. All stool should be removed from outdoor areas, and care should be taken to avoid visiting areas where large numbers of animals visit, as soil in these environments may harbor parasite eggs for many years.
Thankfully, prevention is easy. Most monthly heartworm preventions for dogs and cats also protect against hookworm infection. These products work by eliminating any parasites the animal has contracted within the last 30 days, so it is important to use them regularly year-round for full protection. Animals who have not been on routine heartworm prevention can be dewormed with a general dewormer. Annual or bi-annual fecal floatation testing should also be performed to ensure no failure of preventative medications.

For more information on hookworms, visit the Companion Animal Parasite Council’s (CAPC) webpage on hookworms.