Hook worms are intestinal parasites that are quite common in cats and dogs, especially kittens and puppies. They can also infect humans. Hook worms (also written as “hookworms”) can be found throughout North America, but some types of hook worm are more likely to be found in tropical and semitropical regions. There are several types of hook worm including: A. caninum (canine hook worm), A. braziliense (canine and feline hookworm), U. stenocephala (Northern canine hook worm), and A. tubaeforme (feline hook worm). A. braziliense is more common in tropical and subtropical regions and U. stenocephala is more common in colder northern areas. A. caninum is more likely to infect dogs, foxes, and humans while A. braziliense is more likely to infect dogs, foxes, human skin and cats. U. stenocephala infects dogs, cats, and foxes and A. tubaeforme is more likely to infect cats.

Animals can be infected with hook worms in several ways. They can be infected by ingesting contaminated soil or water; by consuming an infected host; though the skin (larvae can penetrate the skin); or by infecting fetuses through the milk or in the uterus. Hook worm larvae may travel on leaves or other vegetation and even through raindrops. The hook worm waits patiently in or on its transport for the perfect host to come along. The host will either ingest the hook worms or the hook worm will burrow through the host’s skin.

Hook worms that burrow through the host’s skin migrate through the bloodstream and into the trachea and lungs where they are coughed up and swallowed. Once the hook worm attaches itself to the host’s intestinal wall, it will mature, mate, and produce eggs. This completes the life cycle. In some cases, hook worm larvae will migrate to the host’s fat tissues or muscles where it will become dormant. Ingested hook worms will pass down into the intestine and mature. They will remain in the intestine until treated. In some cases, these hook worms may migrate through the host’s tissues and into the trachea where they will be coughed up and swallowed. In some cases, hook worms will end up in the fat and muscle tissues of the host.

Hook worms feed off the host’s blood, which can cause anemia. Anemia is just one of the symptoms of hook worms. Hook worms also cause abdominal pain, pale gums, weakness and fatigue, vomiting, and diarrhea. In pets, hook worms also cause stunted growth, a dull coat, pneumonia, and an emaciated appearance. If left untreated in dogs, cats, foxes, etc., hook worms may also cause death.

In humans, hook worms can cause cutaneous larva migrans also called “creeping eruption.” Because hook worms usually penetrate through the human skin, it will produce lesions under the skin. The lesions appear as red lines under the skin and they may erupt at the skins surface. The lesions cause severe itching, but fortunately, in most hook worm cases that affect humans, the larvae will die in several weeks, and the condition will disappear. In severe cases, however, the larvae may migrate into the tissues, which may cause painful muscles and/or lung disease.

Hook Worm Diagnosis and Treatment

Hook worms is diagnosed by examining the pet’s feces or by evaluating signs of infection. In humans, the doctor will examine the skin for lesions and/or evaluate signs of infection. Hook worms in animals may be treated using a wide variety of oral treatments. These include:

Advantage Multi
Cestex
Droncit
Drontal Plus
Drs. Foster & Smith ProWormer-2
D-Worm
Hartz Advanced Care Liquid Wormer
Heartgard Plus
Interceptor
Iverhart MAX
Iverhart Plus
Nemex-2
Panacur-C
SafeGuard
Sentinel
Sergeants Worm Away
Tri-Heart Plus
Virbantel

It is important to have your pet examined at least once a year, but ideally twice a year for various types of diseases and parasites. If you suspect that your pet may be infected with hook worms, please contact your veterinarian immediately.