Published on
Last updated on
4 min read

Key takeaways

Hookworm disease describes infection with Ancylostoma or Uncinaria parasites. 

  • Hookworms are intestinal parasites and symptoms vary depending on the different species, age of onset, and severity of the worm burden
  • Mild infections in large, healthy dogs usually have no symptoms
  • Lethargy, diarrhea, black stool, pale gums, weight loss and failure to thrive may result in severe cases
  • Hookworm disease is more common in puppies, and severe infections can result in life threatening anemia
  • Transmission of hookworms occurs through oral ingestion or migration through skin
  • Diagnosis is by fecal analysis
  • Blood work identifies secondary symptoms such as anemia
  • Treatment includes antiparasitic medication alongside symptomatic treatment for anemia where necessary
  • Prognosis varies depending on severity of the worm burden and age of onset but most cases respond to medication and have a good prognosis
Are you concerned?

Connect with a vet to get more information about your pet’s health.

Book an online vet

A closer look: Hookworms in Dogs

Hookworm is an intestinal parasite that feeds on blood from the intestinal wall, then drops off and moves to a new location. This feeding action results in multiple areas of damage to the intestinal wall, ongoing blood loss, and anemia.

A mild hookworm infection in a healthy, large adult dog is unlikely to produce any signs of illness at all. Regular parasite control is recommended to minimize exposure for at-risk dogs and humans, especially children.

Adult hookworms are visible to the naked eye, but only rarely pass in the stool or appear in vomit. Eggs that pass in the stool are microscopic.

Connect with a vet to get more information

With DVM, ICH certifications and great reviews by pet parents like you for this symptom

Risk factors

Coughing and itchiness result from the passage of the worms through the respiratory tract or skin during infection.

Hookworm infection is particularly dangerous in puppies and toy breeds where heavy worm burden results in anemia. Hookworm infection is a common cause of puppy mortality and suspected cases require prompt veterinary attention.

Puppies or immunocompromised patients are at higher risk for severe symptoms than adult dogs.

Hookworms are common throughout the United States. As many as 20% of samples checked in the US are positive for hookworms. Hookworms thrive in warm, wet environments, such as the southeast USA.

Possible causes

Hookworm disease is a result of infection with Ancylostoma or Uncinaria species of parasite. Transmission occurs either orally or through the skin. Oral transmission may be a result of ingestion of worms from the environment, by milk from infected mothers, or by infected raw meat, game, or cockroaches.

Eggs in feces contaminate the environment and the larvae that develop after hatching are able to burrow into the skin when dogs are walking, or lying, in areas where hookworm is present.

Main symptoms

Healthy adult dogs with a low worm burden are unlikely to show any symptoms or experience life-threatening blood loss.

Some species of hookworms feed so aggressively they may cause lethal blood loss in a small puppy or dog.

Testing and diagnosis

Diagnostic tools include:

  • Physical examination
  • Blood work
  • Stool analysis

Steps to Recovery

The primary treatment for hookworm infection is antiparasitic medication. In cases where anemia is also present, fluid therapy and blood transfusion may also be required.

Prognosis in hookworm disease varies depending on the age of onset and severity of the infection, with smaller puppies at highest risk of fatal anemia. Adult dogs with a functioning immune system often eliminate infection without any symptoms or show no signs associated with loss of blood. Treatment is normally effective at clearing the worms but must be given for several months. There are reports of rare cases of drug resistant hookworm disease.

Prognosis in cases that receive prompt veterinary treatment is usually excellent.


Prevention of hookworm disease focuses on routine use of a veterinary approved antiparasitic medication and frequent stool analysis. Good hygiene practices reduce the build up of worms in the environment, especially where groups of dogs gather such as breeding kennels, doggy daycare, or parks.

Are Hookworms in Dogs common?

Prevalence varies by age and location. Hookworm infection is more common in the southeast USA than other American regions.

Typical Treatment

  • Antiparasitic medication
  • Fluid therapy
  • Blood transfusion


Maggie Fisher BVetMed CBiol MIBiol DipEVPC MRCVS; Ken Harkin DVM DipACVIM(SAIM); Dwight Bowman PhD - Writing for Vetlexicon
Malcolm Weir, DVM, MSc, MPH; Ernest Ward, DVM; Updated by Amy Panning, DVM - Writing for VCA Animal Hospitals

Our editorial committee

Our medical review team is responsible for validating and maintaining the quality of our medical information.