Medically reviewed by Dr. Irish on April 28th, 2023.
Hookworms in dogs can wreak havoc on your furry friend’s health. This is especially true for young puppies.
As the name implies, hookworms have tiny hook-like mouthparts which allow them to stick to the intestinal wall.
Although hookworms are very small (only about 1/8″ or 2-3mm long), they still manage to absorb a lot of blood from the intestinal wall.
If you suspect your dog has a hookworm infection, it’s important to get your dog to a veterinarian as soon as possible.
Hookworm infection can be treated. Unfortunately, you may not realize your dog has hookworms until they begin to cause serious problems.
The Risks of Hookworm in Puppies
The biggest danger to dogs who have hookworms is the potential for severe anemia. This is especially true of puppies. Young puppies should be dewormed at 2, 4, 6, and 8 weeks of age because they can get worms from their mother.
Left unchecked, hookworms will multiply within the intestines. They will continue to feed and lay new eggs which keeps the cycle going.
Hookworm larvae can burrow through your dog’s skin (such as cracked paws) and cause inflamed, painful skin. They can also get into the eye (ocular larval migrans), especially in humans.
There are different forms of hookworm in puppies. These include:
- Peracute disease (dramatic, life-threatening anemia associated with newborn puppies under 1 week of age)
- Acute hookworm disease (occurs in slightly older puppies in which anemia isn’t as severe but is still serious). This can still be life-threatening if left untreated.
Hookworm Anemia in Puppies
Hookworms can cause inflammation in the intestine and a dangerous drop in the number of red blood cells. This is known as “anemia” and is more commonly seen in young puppies.
Adult dogs, however, can also become anemic for a number of reasons, including parasite infection.
Read about Evan Syndrome in Dogs, a rare disorder in which the immune system destroys blood cells.
Clinical Signs of Anemia in Dogs
Anemia can be tricky to spot, but pet owners should pay attention to the following signs:
- Fatigue or lethargy
- Exercise intolerance
- Decreased appetite
- Increased appetite in some cases
- Pale gums
The Dangers of Hookworms in Adult Dogs
Thankfully, adult dogs are more resistant to hookworm infections than puppies. That said, some adult dogs with a hookworm infection may appear clinically “normal”.
The American Kennel Club Canine Health Foundation has a fantastic fact-sheet on hookworms.
The Life Cycle of the Hookworm
Adult hookworms are very small white worms that thrive in the intestinal tract as long as they have blood to suck.
They’re in no hurry to leave and will repeat their life cycle continuously until medical treatment is administered to the dog to halt the cycle.
It can take 2-3 weeks from the time your dog ingests a hookworm for it to start affecting his or her health.
Egg Stage
At this early stage, the adult hookworm lays microscopic eggs in the dog’s small intestine. The eggs pass through the feces and hatch into larvae.
In order for this to happen, the soil needs to be moist (not wet), and the temperature has to be somewhere in the 75 to 77 degree Fahrenheit zone.
Hookworm larvae can survive weeks in cool, moist soil. However, they won’t survive long in extremely cold or warm, dry temperatures.
Larvae Stage
Hookworm larvae contaminate the soil, leaving humans and animals vulnerable to hookworm infection. Unfortunately, larvae can survive for months in the environment before infecting its host.
The eggs typically hatch within 1 or 2 days where they thrive in warm environments.
At the third stage, the larvae no longer feed on feces but searches for an animal to infect. This is known as the infective larvae and where the biggest danger lies for dogs.
At this point, all it takes is for a dog to sniff the ground, lick the ground, or ingest contaminated soil/feces. That dog then becomes the new host and the cycle continues.
Adult Hookworm Stage
Once ingested, the larvae migrate through the dog’s body until they reach the intestine. This is where they mature into adults. Then they lay eggs and the cycle continues again.
Watch the video below for important information on hookworms and roundworms in dogs
Different Species of Hookworms
The three most common types of hookworms to infect dogs are Ancylostoma caninum, Uncinaria stenocephala, and Ancylostoma braziliense.
The only species of hookworms that can can be transmitted through direct contact of human skin is called N. Americanus.
How Do Dogs Get Hookworms
There are four possible ways for a dog to contract a hookworm infection:
- Oral ingestion (through feces and contaminated soil)
- Skin penetration (for example, through the paws)
- Mother’s milk – hookworms are transmitted through the mammary glands of a pregnant dog leaving young puppies vulnerable
- Grooming – dogs are notorious for rolling around in the grass or dirt. If they happen to pick up the larvae on their fur they can accidentally ingest it through the grooming process.
Clinical Sign of Hookworm Infection in Dogs
There are several signs of hookworms in dogs that owners should be aware of to prevent an infection.
These signs include:
- Anemia (see above for signs of anemia in dogs)
- Pale gums
- Weakness
- Significant weight loss
- Diarrhea (sometimes bloody)
- Failure to thrive in puppies
- Coughing (in some cases)
- Dry or dull coat
Very young puppies can die from dehydration quickly, so if your dog is vomiting and/or has diarrhea, be sure to bring him/her to the veterinarian.
Dehydration is the number one cause of death in young puppies. This can be caused by a number of things including parvo, ingesting toxic substances, and parasitic infection.
The main clinical symptoms are related to bowel discomfort and anemia.
These symptoms can also be a sign of another illness. So, call your vet if you experience any of these symptoms in your dog.
Can Humans Get Hookworms From Dogs?
Yes, hookworms are considered “zoonotic”, meaning they can be transmitted between species. Children are most at risk.
Signs of hookworms in dogs include:
- Diarrhea (children or adult)
- Non-healing skin lesions
- Visual problems
Contact a physician right away if you suspect you or your child has been infected with hookworms.
How Are Hookworms Diagnosed in Dogs?
Hookworms are diagnosed with a microscopic examination of a stool sample using a technique called fecal flotation.
Fecal flotation is a test used to diagnose parasitic worms.
To conduct the test, a fecal sample is mixed with a special fluid that causes the microscopic eggs to float. When they reach the surface the eggs are collected with a glass side. This slide is then examined under a microscope.
Unfortunately, hookworms might not be identified on the first examination because it takes a few weeks for the larvae to mature and produce eggs.
In addition, adult hookworms don’t easily let go of the intestinal wall and may not show up in the dog’s stool.
How Are Hookworms in Dogs Treated?
There are several effective anthelmintic drugs that eliminate hookworms.
Anthelmintic means “to expel parasites from the intestines”. These types of drugs are administered orally with few side-effects.
The downside is that they will only kill adult hookworms, leaving the larvae to hatch, grow, and repeat the cycle.
For this reason, it’s important to continue treatment through several life cycles of the hookworm to eliminate all of them. In rare cases, dogs with severe anemia may need a blood transfusion.
When used according to directions, anthelmintic medications are considered safe and provide a broad spectrum of activity.
Mild side effects of anthelmintic drugs may include:
- Diarrhea
- Drowsiness
- Mild abdominal discomfort
- Nausea
- Vomiting
How to Prevent Hookworms in Dogs
Hookworm larvae are sometimes killed off in colder weather (environmental change) and can succumb to bleach decontamination. A hard frost will also kill hookworms.
The best way to avoid hookworm infection is by taking appropriate control measures. Routine heartworm preventatives also contain ingredients to help prevent hookworm infestations.
Pick Up Dog Poop
If there are no hookworm eggs/larvae in the environment, other animals cannot be infected.
Use reliable, environmentally friendly “poop bags” by turning them inside out and picking up the stool.
Without touching the stool, pull the bag down over the waste and dispose of everything in the trash can.
Cover Sandboxes
Covered sandpits cannot easily be contaminated by dogs and cats passing by.
Deworm Dogs Regularly
With an approved anthelmintic, deworming newborn puppies at 2, 4, 6, and 8 weeks of age and monthly thereafter if possible.
Decrease Risk
Leash your dog and keep him or her confined to the yard. This will prevent your dog from consuming infected prey or contaminated feces.
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Summary
The best prevention is to remove feces from your yard daily and give your pet monthly heartworm prevention that also protects against hookworm infections.
We always recommend consulting your veterinarian first to find out how best to treat and prevent worms in your dog as every dog and situation is different!
You can check your dog’s stool for signs of hookworms; however, they are very small and not easily seen by the naked eye. Maintaining good crate and yard hygiene is probably one of the best ways to keep parasites like worms away from your dog.
Start and keep your dog on a regular anti-parasite oral or topical for long-term effectiveness. In many, if not all, cases, parasites cannot be eliminated with one treatment.
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References
Hookworm Infection in Dogs | VCA Animal Hospitals. (n.d.). Vca. Retrieved April 6, 2023, from https://vcahospitals.com/know-your-pet/hookworm-infection-in-dogs
Anemia in Dogs: Signs & Symptoms | Clemmons Vet. (n.d.). Anemia in Dogs: Signs & Symptoms | Clemmons Vet. Retrieved April 6, 2023, from https://www.animalhospitalofclemmons.com/site/veterinary-pet-care-blog/2020/06/12/anemia-dogs-signs-symptoms
Immune-Mediated Hemolytic Anemia (IMHA) in Dogs. (n.d.). MSPCA-Angell. Retrieved April 6, 2023, from https://www.mspca.org/angell_services/immune-mediated-hemolytic-anemia-imha-in-dogs/
Ancylostoma Caninum. (n.d.). ADW: Ancylostoma caninum: INFORMATION. Retrieved April 6, 2023, from https://animaldiversity.org/accounts/Ancylostoma_caninum/
E. (n.d.). Hookworm Lifecycle in Dogs. Hookworm Lifecycle in Dogs. Retrieved April 6, 2023, from https://pet.elanco.com