Hookworms in Dogs

Written by Small Door's medical experts

Hookworms are parasites that pose particular dangers to puppies, as infections can lead to fatal complications. Knowing the signs of hookworms will help you identify a possible infection while it can still be treated.

In This Article

What are hookworms in dogs?

Hookworms are a type of intestinal parasite that attaches to the intestinal walls of infected animals. If left untreated, a hookworm infestation can be fatal, especially in puppies.

The most common species of hookworm in dogs is Ancylostoma Caninum. Researchers estimate that a dog can lose up to 0.1mL of blood from a single hookworm, and that blood loss can eventually lead to potentially fatal cases of anemia in puppies.

Signs and symptoms of hookworms in dogs

Symptoms of hookworms are most commonly seen in puppies, although hookworms can affect adult dogs as well. These symptoms may include:

  • Anemia

  • Diarrhea

  • Melena (dark, tarry stool)

  • Anorexia

  • Overall weakness

  • Dermatitis

  • Pneumonia and lung damage

Hookworms are especially dangerous for young puppies and can have long-term effects on their growth. Hookworms attach to the intestinal wall, and heavy parasite loads can lead to potentially fatal anemia as well as ulceration at the feeding sites. It leads to a dark, bloody stool called melena, which occurs when the digested blood passes through the gastrointestinal tract.

Hookworms also lead to overall weakness and loss in condition. In severe cases, it can even lead to lung damage and pneumonia.

Healthy adult dogs do not always show signs of hookworms. However, these dogs do pose a potential threat for puppies, as they can introduce hookworm into the puppy’s environment. Sometimes, dermatitis can result in a dog’s paws from migrating hookworm larvae.

How do dogs get hookworms?

Dogs often contract hookworms as puppies, either through their mother’s milk or contact with infected environments.

Common causes of hookworms include:

  • Ingestion of larvae from the environment

  • Milk of infected lactating females

  • Skin penetration by larvae

Hookworm eggs pass through the feces of infected dogs into the environment, where they hatch in warm, moist soil. Dogs can ingest the larvae from the environment, or in some cases, can become infected after lying in infected dirt, as the larvae can penetrate the skin and migrate through the body to the intestines. In puppies, skin penetration poses an additional risk, as the larvae first migrate to the lungs, where they are then coughed up and swallowed. This can lead to lung damage and pneumonia.

Another common route of transmission in puppies is through the colostrum or milk of infected mothers. Female dogs do not always present with symptoms of hookworms. In fact, larvae in adult females can remain dormant in their somatic tissues until they are activated by pregnancy.

What environment are hookworms most common in?

Hookworms are typically found in environments that are warm and moist. These conditions, along with overcrowding and poor sanitation can allow hookworms to thrive and cause severe infection in dogs.

Diagnosing hookworms in dogs

Veterinarians diagnose hookworms in dogs based on clinical signs, like anemia, and evidence of hookworm eggs in fecal analysis. Your veterinarian will most likely ask you to bring in a fresh sample of your dog’s poop, which will be analyzed for eggs. In heavy parasite loads, adult worms may even show up in fecal flotations.

Hookworm eggs are small, thin-walled, and oval-shaped with two to eight circular structures within the egg. Unlike some parasite eggs, they are not visible to the naked eye. Eggs are not always present in fecal samples, especially in very young puppies, as the hookworms have not had a chance to complete their life cycles yet. In these cases, veterinarians often suggest treating anyway, as the medication for treating hookworms is relatively benign and the benefits outweigh potential risks.

In severe cases, your veterinarian may also recommend additional diagnostic testing, like bloodwork, ultrasounds, or radiographs to determine the extent of the damage caused by the hookworms.

Treatment for hookworms in dogs

Treating for hookworms include deworming medications like fenbendazole, pyrantel, and milbemycin. These medications are generally considered safe and do not carry many side effects, and fenbendazole is approved for use in young puppies.

To treat a hookworm infection, veterinarians recommend deworming pregnant females to reduce the risk of transmission through mammary tissue. Sanitary living conditions will also reduce the risk of infection, as hookworm eggs will be unable to hatch. You can ensure sanitary living conditions by regularly cleaning kennels and living spaces and by picking up poop immediately. These steps lower the risk of hookworm larvae entering the environment and reinfecting dogs.

Puppies that are at high risk of infection can be started on treatment at 2 weeks of age and can be continued until 12 weeks of age, at which time you can put them on a monthly preventative. In severe cases, puppies may need supportive care. Pneumonia and lung damage will require additional treatment protocols, as will cases of severe anemia. Your veterinarian may recommend hospitalization, supportive fluids, and blood or plasma transfusions as needed.

Is there a cure for hookworms in dogs?

There is a cure for hookworms. Dewormers and monthly preventatives can not only cure hookworms but also eliminate the risk of future infections.

Are hookworms contagious for humans or other pets?

Hookworms are a zoonotic disease, which means they can be spread between animals and humans. Your dog cannot transmit hookworms to you directly, but hookworm eggs can pass through your dog’s feces and into the environment. If humans contract the disease from the environment, the larvae will penetrate the skin and result in cutaneous larva migrans. It’s especially dangerous in small children, as larva migrans in the eyes can lead to blindness. If you’re concerned you may have contracted hookworms from your pet, seek the advice of your doctor.

What is the cost of treating hookworms in dogs?

Hookworms are relatively inexpensive to treat. You can expect to pay for the cost of the office visits, the medication, and follow-up fecal analysis to make sure the infection is clearing. You may also want to calculate the cost for monthly preventatives that treat hookworms, as these will prevent future infections.

Recovery and management of hookworms in dogs

Your dog’s recovery time from hookworms will depend on your dog’s age, overall health, and the severity of the infection. Hookworms can be fatal in puppies, but overall most cases of hookworm infections have a good prognosis.

The most significant management issue with hookworms is reducing the risk of infecting the environment. Picking up poop immediately from the yard minimizes the risk of larvae infecting the soil, and regularly cleaning and disinfecting kennels and runs will help prevent eggs from hatching. Maintaining good hygiene practices will also lower the chances of a zoonotic infection in humans.

Preventing hookworms in dogs

Hookworms are entirely preventable. Puppies should be routinely dewormed (at Small Door we recommend deworming at least twice by 16 weeks of age) and should have fecal samples tested every four weeks. Breeders should also consult with their veterinarians to determine the best deworming schedule for dams, puppies, and other dogs in the household that harbor a potential transmission risk.

You can also protect your dog from hookworms by giving them a monthly preventative that treats hookworms. Several brands of heartworm preventatives are combination preventatives, and also treat hookworms. Monthly preventatives eliminate the risk of your dog contracting these parasites, which in turn lowers the risk of a potential human infection. Learn more about why monthly heartworm preventatives, and flea and tick preventatives are important, and speak to your veterinarian to determine which preventatives are most suitable for your dog.

Is there a vaccine for hookworms?

Hookworms are not a viral disease. There is no vaccine for hookworms, but there are monthly preventatives that will prevent it.

Summary of hookworms in dogs

Hookworms are an intestinal parasite that can cause anemia, weakness, lung damage and pneumonia. While adults may not always show symptoms, hookworms are particularly dangerous for young puppies and can have long-term effects on their growth or even be fatal. Thankfully, hookworms are a preventable condition that can be kept at bay with appropriate deworming schedules and monthly preventatives. Speak to your veterinarian today about how you can protect your dog from hookworms.

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