By Catherine Barnette, DVM
Hookworms are an intestinal parasite (worm) that lives in the small intestines of dogs and other animals. The most common species of hookworm is Ancylostoma caninum, although there are other species of hookworms that can also infect dogs. This parasite primarily causes problems in young puppies, but it can also affect adult dogs.
Hookworms get their name from their body shape. These small worms (only half an inch long) have a body that bends to form a hook shape. They use their mouthparts, which contain either teeth or cutting plates, to attach to the intestinal wall. Once attached, hookworms begin sucking blood from their host. This can lead to anemia (lack of red blood cells), which is the most common problem associated with hookworms. In addition to causing anemia, severe hookworm infestations can cause significant intestinal inflammation and damage.
What Causes Hookworms in Dogs?
To better understand what causes hookworms in dogs, it’s helpful to think about the hookworm life cycle in dogs first.
When a dog has a hookworm infection, adult female hookworms lay eggs, which are then passed in the dog’s feces (stool). Within a day or two of being passed in the environment, the eggs develop into larvae and mature to an infective stage. Infective hookworm larvae remain active in the soil for up to several months, which means they can reinfect the same dog or infect other pets and even people.
There are a few ways that a dog can become infected with hookworms:
- Ingestion of hookworm larvae: If a dog eats contaminated feces (or grass/leaves contaminated by infected feces), hookworm larvae enter the intestinal tract. In two to four weeks, these larvae will mature and create an adult intestinal hookworm infection.
- Skin contact with hookworm larvae: If a dog walks through (or lays on) contaminated stool or soil, infective larvae can migrate across the skin and enter the body’s tissues. These tissue larvae remain inactivated, in cysts, until they are activated by a chemical signal. The death of adult intestinal hookworms signals inactivated larvae to mature and travel to the intestines, creating a new infection.
- From mother to puppies: In female dogs, pregnancy signals inactivated larvae to mature and travel to the mammary glands. The larvae are passed in the milk to the nursing puppies.
Hookworms are a zoonotic parasite, meaning that they can infect both animals and humans. Cases of hookworms in humans from dogs can occur. If a human ingests soil contaminated by dog feces (for example, in the case of a young child who plays in contaminated soil and eats without washing his hands), an intestinal infection can develop. Like dogs, humans can also be infected through skin contact with contaminated soil. Hookworm larvae can penetrate unprotected skin, causing a rash called cutaneous larva migrans.
Hookworm Symptoms in Dogs
The signs of hookworms in dogs are variable. Severe signs are typically seen in young puppies, due to the puppies’ small size and the significant effects of blood loss in growing animals. In newborn puppies, severe anemia and death can occur as early as one week after birth, before the adult hookworms even begin laying eggs. In older puppies, anemia can cause lethargy, poor appetite, and failure to gain weight appropriately. If you look closely at the gums of an anemic puppy, you may notice that they are pale or white, instead of having the normal healthy pink color. Even in older puppies, hookworms can be fatal.
In adult dogs, the signs of hookworms vary depending on the severity of the infection. Like puppies, the most common effect of hookworms in adult dogs is anemia. Adult dogs with anemia are often lethargic, reluctant to exercise, and may demonstrate shortness of breath. Additionally, some dogs may develop dark, tarry stools due to intestinal inflammation caused by hookworm infection.
Diagnosing Hookworms in Dogs
Your veterinarian will diagnose hookworms by examining a sample of your dog’s feces under a microscope to look for eggs.
Clients often ask, “can you see hookworms in dog poop?” Unfortunately, the answer is no. A dog can have a severe hookworm infestation without shedding any adult worms. Therefore, veterinarians rely on microscopic examination for eggs or fecal antigen testing to diagnose hookworms. Antigen tests look for worm proteins that can be detected if your dog has an infection.
In addition to fecal parasite testing, which is performed specifically to look for hookworms, dogs with signs of anemia may also undergo blood tests to assess the severity of their anemia and look for evidence of other illnesses. Dogs with severe gastrointestinal signs may also need abdominal X-rays to rule out other causes of these signs.
How to Treat Hookworms in Dogs
All dogs diagnosed with hookworms should receive veterinary care immediately. Your veterinarian is the best person to advise you on how to get rid of hookworms in dogs. Unfortunately, there are no home remedies for hookworms in dogs and a delay in treatment can have serious effects on your pet. In addition to helping your dog recover quickly, prompt treatment of infected animals decreases the likelihood that other people or animals will encounter infectious hookworms in dog stool.
Hookworm Medicine for Dogs
Hookworms can be effectively treated with a number of common dog dewormers but not all, so it’s worth checking. It is important to remember, however, that these treatments are not effective against all stages of hookworms. Therefore, it is not uncommon for pets to develop an apparently “new” infection after deworming.
Given how common and problematic hookworm infections can be, veterinarians recommend that pets receive regular deworming for hookworms and other intestinal parasites.
In most cases, monthly deworming is accomplished by administering a heartworm preventive that also offers protection against common intestinal worms. Interceptor® Plus (milbemycin oxime/praziquantel), for example, is a tasty monthly chew that treats and controls tapeworm, hookworm, roundworm, and whipworm infections in dogs while also preventing heartworm disease.
See important safety information below for Interceptor® Plus.
Cost to Treat Hookworms in Dogs
The cost of treating hookworms in dogs can vary significantly, depending on the size of the dog, the severity of the disease, and local pricing factors. While a dog showing minimal signs may require only oral dewormer, a puppy with severe anemia may require hospitalization and blood transfusions. In the case of intestinal parasites, protection is nearly always less costly than treatment.
- Office visit and fecal parasite testing: $75-$125
- Dewormer to eliminate hookworm infection: $25-$100
- Additional diagnostics and hospitalization (may be required in severely ill dogs): $500-$2,000
- Monthly parasite protection (to prevent heartworms and control intestinal worms): $8-$12/month
Hookworm Prevention in Dogs
Pet parents can take a number of steps to decrease their dog’s likelihood of developing a hookworm infection, including:
- Keep dogs on a leash when outdoors, to minimize the likelihood of the dog finding and eating objects off the ground. This can decrease the likelihood that they will become infected by hookworms in dog stool.
- Pick up dog stool regularly, to decrease the likelihood of environmental contamination.
- Observe community leash laws and restrictions in designated public spaces where dogs might not be allowed, such as children’s play areas.
- Use a monthly parasite protection medication, such as Interceptor® Plus, to control intestinal worm infections, in addition to heartworms.
Interceptor Plus Indications
Interceptor Plus prevents heartworm disease and treats and controls adult roundworm, hookworm, whipworm, and tapeworm infections in dogs and puppies 6 weeks or older and 2 pounds or greater.
Interceptor Plus Important Safety Information
Treatment with fewer than 6 monthly doses after the last exposure to mosquitoes may not provide complete heartworm prevention. Prior to administration of Interceptor Plus, dogs should be tested for existing heartworm infections. The safety of Interceptor Plus has not been evaluated in dogs used for breeding or in lactating females. The following adverse reactions have been reported in dogs after administration of milbemycin oxime or praziquantel: vomiting, diarrhea, decreased activity, incoordination, weight loss, convulsions, weakness, and salivation. For complete safety information, please see Interceptor Plus product label or ask your veterinarian.
Disclaimer: The author received compensation from Elanco US Inc., the maker of Interceptor Plus, for her services in writing this article.
Interceptor is a trademark of Elanco or its affiliates.
© 2020 Elanco. PM-US-20-0720
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