A woman pets her dog while holding a tennis ball in her hand
A woman pets her dog while holding a tennis ball in her hand

Hookworms in Dogs: What You Need to Know

Hookworms are a serious threat to all dogs but can be especially dangerous to young puppies. It’s important for pet owners to understand what hookworms are, how they affect your dog, and what you can do to prevent them. Keep reading to learn how to protect your dog from the dangers of hookworm infection.

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Image of hookworms in intestines

What Are Hookworms in Dogs?

Hookworms are tiny intestinal parasites that live in your pet’s digestive system. There are 3 species of hookworms that affect dogs (Ancylostoma caninum, Ancylostoma brazilense, and Uncinaria stenocephala). 


As their name suggests, hookworms hook themselves to your dog’s intestinal lining and feed on their blood. This causes internal blood loss, which is a danger to all dogs, but particularly to young puppies who may not survive without a blood transfusion.. 

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Image of microscopic hookworm eggs

What Do Hookworms Look Like?

Adult hookworms are very small, at only 10-20 millimeters in length. They may look like tiny, thin strings in your dog’s feces. However, it’s important to note that you won’t always be able to see hookworms. The only way to diagnose a hookworm infection is to have your dog examined by a licensed veterinarian.


When hookworms reproduce, their microscopic eggs are ejected into your dog’s digestive system. The eggs then pass into your pet’s environment via your dog’s feces. The hookworm larvae that hatch from the eggs live in the soil and can infect your dog again through contact.1

How Do Dogs Get Hookworms?

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There are many ways your dog can become infected with hookworms. Understanding the various means of transmission is necessary to protect your dog from hookworm infection. 


  • Direct Contact to Skin: If your dog comes in contact with hookworm infected soil or vegetation, the larvae  can burrow through your dog’s skin and infect them.1
  • Oral Ingestion: Your dog can also contract hookworms if they consume infected soil. This can happen if they eat grass or groom or lick themselves when covered in infected dirt or feces.1 
  • In Utero or While Nursing: Infected mothers can pass hookworms to their puppies either in utero or through the mother’s milk when nursing.2 


Hookworms thrive in warm, moist, and dark environments, like underneath leaves or in moist sandy areas. This also applies to overcrowded environments, like unsanitary kennels with poor sanitation habits, or areas where proper hygiene isn’t followed.

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What Are the Signs of Hookworms?

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With so many ways for your dog to become infected with hookworms, it’s important to always be on the lookout for signs of infection. There are many indicators that your dog has contracted hookworms, including:2


  • Anemia
  • Weight loss or failure to gain weight 
  • Skin irritation  
  • Dehydration 
  • Bloody diarrhea
  • Weakness
  • Loss of appetite 


If your dog exhibits any of these signs, make an appointment with your vet immediately.

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How Are Hookworms Diagnosed?

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The only way to properly diagnose a hookworm infection is to take your dog to a licensed veterinarian. If your vet suspects that your dog has an infection, they will perform something called a fecal float. In this test, the vet will examine a stool sample from your dog to look for hookworm eggs.2


Young puppies should be tested for hookworms more frequently than older dogs. The Companion Animal Parasite Council (CAPC) recommends that your puppy be tested at least 4 times in the first year of life, and then twice per year as they advance into adulthood.2

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What Are the Dangers of Infections?

Hookworms attach to your dog’s intestinal lining and feed on their blood. This results in internal blood loss, which can be a serious threat to dogs. In older dogs, this can result in weight loss or diarrhea. In young puppies, the effects can be even more severe, often requiring a blood transfusion.1

Infection to Humans

You might be wondering, are hookworms a danger to humans as well as to dogs? It is possible for hookworms to infect humans if they encounter infected soil. This can happen while gardening or walking barefoot through your yard.


However, although hookworms can technically infect you, they won’t mature in humans. They may burrow into your skin and cause itching, which is a condition known as cutaneous larva migrans (CLM), or “creeping eruption.” Because maturation cannot occur in humans, the hookworm larvae will typically die within a few weeks, but the itch will persist much longer.    

How to Treat Hookworms in Dogs

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Working closely with your veterinarian is the best way to treat a hookworm infection in your dog. Typically, your vet will prescribe an anthelmintic, or dewormer. This type of medication is typically given orally and is designed to kill adult hookworms. Because it only targets adult worms, your vet may recommend another treatment 2 to 4 weeks later. This will kill any new adult hookworms that have developed from larvae.2


In the case of a severe hookworm infestation, your dog may require a blood transfusion to treat the blood loss. This is especially common in young puppies with hookworm infection. 

A veterinarian shows a client information about their pet's health A veterinarian shows a client information about their pet's health

Hookworm Prevention for Dogs

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Preventing hookworm infection in dogs is just as important as treating it. There are several steps pet owners can take to reduce the risk of hookworms, including:


  • Clean up your dog’s poop immediately. Hookworm eggs pass through feces, so picking it up immediately can prevent the eggs or larvae from infecting the surrounding soil.
  • Practice proper kennel hygiene. Hookworms thrive in moist, warm, and unsanitary environments. Cleaning up after your dog and disinfecting their environment on a regular basis can help prevent hookworm infection.
  • Use caution when boarding your dog. If you must board your dog or send them to doggy daycare, pay attention to the surroundings. Don’t take your dog to a facility if it seems dirty or overcrowded. 
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A woman feeds her golden retriever puppy a heartgard chew | HEARTGARD® Heartworm Protection

Treat All Pets in Your Home

Another important step for pet owners is to treat all pets with a parasite control product. 


HEARTGARD Plus chews treat and control all 3 species of hookworms and are approved for use in puppies as young as 6 weeks of age with no minimum weight requirement.