Hookworms are parasitic worms that infect the gastrointestinal (GI) tract of dogs and cats. Pets become infected after eating or drinking something contaminated with hookworm eggs (e.g. soil, other animal's stool or feces, etc.). Adult hookworms attach to the intestinal wall lining and feed on the dog or cat's blood. Anemia, or low red blood cells, may occur. In some pets infected with high numbers of worms, anemia from blood loss can be life-threatening.

Symptoms and Identification

Dogs and cats with mild hookworm infections, or those infected with only a few worms, may not show any symptoms. Diarrhea or loose stool and a pot-bellied appearance is common, especially in puppies and kittens. The diarrhea may have blood in it or appear very dark. Sometimes worms will be present in the stool.

If the pet is infected with many worms, symptoms of anemia can be seen. Pale skin and gums, poor appetite, decreased activity, and/or not moving much are common symptoms of hookworm anemia.

Hookworm infection is most easily diagnosed by examining the pet's stool under a microscope to look for hookworm eggs. Fresh stool is best.

Affected Breeds

Any dog or cat breed can be infected. Young animals (i.e. those about 6 months of age) are more likely to be infected than older pets, and these infections are often more serious.


For pets with mild or no symptoms, a dewormer (e.g. pyrantel pamoate) may be the only treatment needed. In some cases, the treatment must be repeated in a few weeks to ensure all the worms are gone. Veterinarians will often recheck a stool sample to confirm the treatment worked.

In pets that have anemia, hospitalization and a blood transfusion may be necessary. Pets, especially the very young, may become ill very quickly. Treating sick pets at the first sign of illness can help improve their outcomes.

Veterinary Cost

The cost of a fecal and deworming medication ranges from $50-150, depending on the severity of infection and the pet's size. Blood transfusions and hospitalization can be very costly, ranging from $500-1,500 in some cases.


Many heartworm prevention products also prevent intestinal parasites like hookworms. As long as the pet remains on a preventive medication, hookworm infections are very rare. Immediate removal of stool or fecal material can also help prevent infection.

Rarely, pregnant or nursing pets can accidentally infect their young. Deworming the mother at certain intervals can prevent infection in the babies. Always ask a veterinarian for advice and recommendations before trying to give a pregnant or nursing pet any medication.

Humans can become infected with hookworms too. Symptoms more commonly involve migration or movement of the worms under the skin after contact with contaminated soil (e.g. sandboxes). Preventing pets from developing infection also serves to protect people as well. Yearly fecal examinations by the veterinarian will confirm that a pet is healthy and free of hookworms.


1. CAPC: Intestinal Parasites - Hookworms. Companion Animal Parasite Council, 2012.

2. Blagburn BL: Update on Treatment and Control of Parasites and Parasitic Diseases of Companion Animals. Atlantic Coast Veterinary Conference 2005.

3. Ballweber LR: Zoonotic Helminths. Western Veterinary Conference 2004.

4. Huspeni TC: Pets, People, and Parasites: The Dating Game. Atlantic Coast Veterinary Conference 2010.

5. Weese JS: Peregrine A Parasitic Diseases. Companion Animal Zoonoses Wiley-Blackwell 2011 pp. 36-40.

6. Jarvinen JA: Hookworms (Ancylostomiasis). Blackwell's Five Minute Veterinary Consult, Canine, and Feline, 5th ed. Wiley-Blackwell 2011 pp. 590.