Among the intestinal worms that can plague dogs, hookworms are less widely known than most. However, these tiny worms can cause significant damage to a dog's intestines. All dog owners should understand the alarming ways pets (and humans) can become infected with hookworms and how to address an infection.
What are Hookworms?
Hookworms are an intestinal parasite that live within the digestive tract of a dog. These small worms have hook-like mouth parts (hence their name) that they use to latch onto the walls of the intestines. They feed on the blood of their host, and a single worm can ingest up to 0.2 milliliters (almost ¼ teaspoon) of blood each day. This may not seem like much, but when multiple worms feed over an extended period, this can have detrimental effects on a dog. To facilitate feeding, hookworms also secrete an anticoagulant to keep the blood from clotting. This substance in the areas of attachment can create bleeding ulcers, among other negative health effects.
How to Identify Hookworms in Dogs
Because hookworms attach themselves to the intestinal wall of dogs, it's unlikely that you'll ever see one of these worms, even in significant infestations. They are not readily eliminated in a dog's stool and can survive for several months or even years within a host. These worms are also very small, ranging from 10 to 20 millimeters in length, which is only around 1/2 inch. Despite being out of sight, you may notice a few or many of the symptoms of hookworm infection.
Symptoms of Hookworm Infection
Although it's possible for dogs carrying hookworms to show no signs at all, as the infestation progresses and the worms wreak havoc on the intestines, you will likely see the following symptoms.
- Diarrhea
- Diarrhea with fresh, red blood
- Diarrhea with dark, digested blood
- Pale gums
- Weakness
- Lethargy
- Weight loss
- Not eating
- Dull fur
- Itchy paws
- Coughing
- Vomiting
How do Dogs Get Hookworms?
Hookworms have three life stages: egg, larvae, and adult worm. Once a dog becomes the host of an adult hookworm, the worm produces hundreds of eggs, which are passed in the dog's feces. The eggs develop into larvae in the environment within a few days. These infective larvae can then live in the soil for up to four weeks and may either be ingested by a dog or burrow into the skin between a dog's paw pads, then make their way to the digestive tract. Once in the intestines, the larvae mature into adult worms, attach to the walls, feed on blood, and reproduce.
As mentioned, there are a few alarming ways that a dog can contract hookworms.
- Ingesting infected larvae through feces or the environment.
- Walking or laying on infected soil where larvae then penetrate the paw pads and migrate to the intestines.
- Through nursing from the mother dog's milk.
Can Humans Get Hookworms from Dogs?
The hookworm's ability to penetrate skin makes them a danger to humans, as well. When a dog has hookworms, they shed the eggs and larvae into the environment. Even if the feces have been picked up, the larvae can remain. If a person spends time with their bare skin in this infected soil, for example, gardening without gloves, walking on a beach while barefoot, or playing in a sandbox, hookworm larvae can penetrate the skin.
These canine larvae tend to stay under the dermal layer of humans as cutaneous larva migrans or "creeping eruptions." They look like raised, twisting tracks which may change with the movement of the worm. In rare cases, larvae can migrate deeper into tissue and may make their way to the lungs or eyes. The best way to protect your dog and your family is through early treatment of any infections, prevention, and environmental decontamination.
Hookworm Treatment Options for Dogs
If a fecal test reveals that your dog has hookworms, an oral deworming medication will be prescribed. You'll likely have to remedicate your pet at intervals to kill all stages of the worm. However, other treatments may be recommended to address any symptoms caused by the infections, such as diarrhea, ulcers, or dehydration. In severe cases with significant blood loss, most commonly seen in puppies, hospitalization with a blood transfusion may be necessary.
Preventing Hookworm Infections
Prevention is important to keep hookworm larvae out of your yard and protect your dog from any larvae they might pick up in other environments.
- All puppies should be on a deworming schedule to kill any hookworms transmitted through nursing. Ideally, this medication is given every two weeks until the puppy is 8 weeks old. Ask your vet about a specific plan for your dog based on their age and risk.
- Discuss a possible deworming schedule for pregnant dogs to prevent transmammary transmission.
- Keep your dog on a monthly prevention that protects against heartworms and also kills hookworms and other intestinal parasites.
- Pick up feces in your yard right away.
- Clean up after your dog in public areas.
- Have your dog's stool routinely tested for worms. The Companion Animal Parasite Council recommends doing this twice yearly (more often for puppies: four times in their first year of life).
- Any hookworms in the environment should die after a few months or can be killed by cold temperatures. However, if you'd like to decontaminate your yard, some veterinarians suggest using boric acid in the soil.
Your Dog Isn't Off the Hook
Hookworms are one of the most common intestinal parasites that affect dogs. Even if your pet isn't showing obvious signs of infection, they could be plagued by these tiny worms. Treating and preventing hookworms will protect your dog and yourself from these blood-sucking parasites.
