Hookworms in Dogs: Symptoms, Treatment & Prevention

Have you noticed diarrhea, pale gums, weakness, or poor growth in your puppy? Hookworms in dogs can cause these symptoms and, in young puppies, a heavy infection can lead to dangerous blood loss.

Hookworms are tiny intestinal parasites, but they can cause surprisingly serious problems. They attach to the intestinal wall and feed on blood, which is why anemia is one of the biggest concerns.

The good news is that hookworm infections are treatable. The tricky part is that treatment may need to be repeated, and dogs can become infected again when contaminated soil or other sources remain around them.

This guide covers how dogs get hookworms, the symptoms to watch for, what hookworms can look like in dog poop, how veterinarians diagnose and treat them, why puppies are especially vulnerable, and how to protect your dog and your family.

Veterinary health note: This article is for general education and does not replace veterinary diagnosis or treatment. A puppy with pale gums, weakness, severe diarrhea, collapse, or other signs of significant illness should be evaluated promptly by a veterinarian.

What Are Hookworms in Dogs?

Hookworms are small parasitic worms that live in a dog’s intestinal tract. They get their name from the hook-like mouthparts they use to attach themselves to the intestinal lining.

Several species can infect dogs, including Ancylostoma caninum, Ancylostoma braziliense, and Uncinaria stenocephala.

You usually won’t see adult hookworms in your dog’s stool. They are small and remain attached to the intestinal wall, unlike some larger worms that owners can spot easily.

Their size can be misleading.

Hookworms feed on blood and tissue fluids. A large number of them can cause intestinal bleeding and a significant drop in red blood cells. Puppies are particularly vulnerable to severe anemia.

How Do Dogs Get Hookworms?

Dogs can become infected with hookworms through several routes.

Contaminated soil

Hookworm eggs leave an infected dog through feces. Under suitable environmental conditions, the eggs hatch and develop into infective larvae.

Another dog can then become infected by contacting contaminated soil and swallowing the larvae while sniffing or grooming.

Warm, moist environments can allow hookworm larvae to survive and remain infective.

That means a dog doesn’t have to eat another dog’s poop to become infected.

Through the skin

Hookworm larvae can also penetrate a dog’s skin.

A dog walking, lying, or playing on contaminated ground may pick up larvae through the skin. The larvae can then migrate through the body before reaching the intestinal tract.

This is one reason keeping contaminated areas clean matters even when your dog doesn’t eat things off the ground.

From infected prey

Dogs that hunt or eat small animals can become infected by consuming prey that contains hookworm larvae in its tissues.

For dogs that love chasing wildlife, this is another exposure route worth remembering.

From mother to puppy

Puppies have an additional problem.

Hookworm larvae can remain dormant in a female dog’s tissues and become active during pregnancy or nursing. Those larvae can accumulate in the mammary glands and infect puppies while they nurse.

This is why puppies can develop hookworm infections even when they have barely had any exposure to the outside environment.

Hookworms in Puppies: Why They Are So Dangerous

Puppies are much more vulnerable to serious hookworm disease than healthy adult dogs.

Hookworms feed on blood, and a growing puppy has a smaller blood volume to begin with. A heavy infection can therefore cause anemia quickly. Cornell notes that A. caninum can cause acute, significant anemia and even death in young puppies.

Puppies may develop:

• Pale gums
• Weakness
• Lethargy
• Diarrhea
• Bloody or very dark stool
• Vomiting
• Poor appetite
• Weight loss
• Poor growth
• Dehydration
• A dull coat

A puppy that seems unusually tired deserves attention. Don’t assume it is simply sleepy because it is young.

And if the gums look pale or almost white, contact a veterinarian promptly.

Symptoms of Hookworms in Dogs

The symptoms depend partly on the number of worms present and the dog’s age and health.

Some dogs have few obvious signs. Others develop gastrointestinal problems or anemia. Puppies tend to be affected more severely.

Pale gums

Pale gums are one of the symptoms owners should take seriously.

Hookworms consume blood and can cause ongoing intestinal blood loss. Anemia may leave the gums looking much lighter than their normal healthy pink color.

Diarrhea

Hookworm infections can cause diarrhea and intestinal irritation.

The stool may sometimes contain digested blood, which can make it appear very dark or tar-like. Cornell lists melena, or digested blood in stool, among the clinical signs of hookworm infection.

Weakness and lethargy

A dog losing blood may become tired, weak, or less interested in normal activities.

This can be especially noticeable in puppies that suddenly stop playing or struggle to keep up with normal activity.

Weight loss and poor growth

Heavy infections can interfere with a puppy’s ability to grow normally.

A puppy that is eating but failing to gain weight deserves a veterinary evaluation, particularly if diarrhea or pale gums are also present.

Coughing

Hookworm larvae can migrate through the lungs before reaching the digestive tract.

Respiratory signs such as coughing can occur during this stage, although intestinal and anemia-related signs are generally more important clinically.

Itchy skin or irritated paws

Larvae that penetrate the skin can cause skin irritation.

Cornell reports red, itchy lesions between the toes in some affected dogs.

Your dog licking its paws doesn’t automatically mean hookworms are involved, but persistent irritation combined with gastrointestinal symptoms is worth mentioning to your veterinarian.

What Do Hookworms Look Like in Dog Poop?

This is where hookworms are different from many other intestinal worms.

You usually will not see adult hookworms in your dog’s poop.

They are very small and remain attached to the intestinal wall, so finding an obvious worm in the stool is uncommon.

What veterinarians look for instead are microscopic hookworm eggs in a fecal sample.

The eggs cannot be reliably identified by simply looking at the stool at home.

So if your dog has diarrhea, anemia, poor growth, or other symptoms, don’t rule out hookworms just because you can’t see a worm.

How Are Hookworms in Dogs Diagnosed?

Veterinarians commonly diagnose hookworms through fecal testing.

A fecal flotation test can identify hookworm eggs under a microscope. Fecal PCR testing can also be used in some cases.

There is an important catch with puppies.

Hookworms can begin causing blood loss before the worms produce eggs that appear in the stool. Cornell specifically notes that puppies infected through nursing may develop acute anemia before passing detectable eggs.

That means a negative fecal test doesn’t always rule out hookworms in a very young, sick puppy.

If anemia is suspected, your veterinarian may also recommend blood work to evaluate the dog’s red blood cell levels.

Hookworm Treatment for Dogs

Hookworm treatment uses anthelmintic, or deworming, medication that targets the parasites.

One commonly used medication is pyrantel pamoate. Other veterinary-approved anthelmintic medications may also be used depending on the dog and the circumstances.

The important part is the follow-up.

Some treatments kill adult hookworms but don’t eliminate every immature stage in the body. For that reason, treatment is commonly repeated every two to three weeks to catch worms that mature after the initial treatment.

Don’t assume that one dose means the problem is permanently gone.

Your veterinarian may recommend a specific treatment schedule based on your dog’s age, weight, symptoms, fecal results, and risk of reinfection.

What happens after treatment?

There is another detail owners don’t always expect.

When hookworms detach from the intestinal wall, they can leave small ulcerated areas that may continue bleeding for several days. Cornell notes that anemia can therefore temporarily worsen after treatment in some dogs.

A severely anemic dog may need additional supportive treatment.

In serious cases, veterinary care can include fluids, gastrointestinal support, and blood transfusion.

That is why a weak or pale puppy should not be treated as a simple routine deworming case.

Hookworm Medicine for Dogs: Does One Dose Work?

It depends on the medication and the stage of the infection.

Many dewormers are effective against adult hookworms, but immature stages may survive the first treatment. Repeat dosing is therefore often part of the treatment plan.

Some monthly parasite preventives also help control hookworms and reduce the chance of reinfection.

Cornell notes that certain monthly preventives can kill larval stages, although dormant tissue stages may not be affected.

This distinction matters.

A dog can appear better after treatment and still need continued prevention and follow-up.

Can Hookworms Come Back?

Yes.

Reinfection is common when dogs continue to encounter contaminated environments.

An infected dog releases parasite eggs into the environment through feces. Those eggs develop into larvae, and the larvae can remain infective under suitable conditions.

That creates a cycle:

Dog becomes infected → eggs leave in feces → larvae develop in the environment → dog encounters larvae → infection starts again.

Breaking that cycle requires more than medication.

You also need to reduce environmental exposure.

How to Prevent Hookworms in Dogs

Prevention works best when medication and environmental management are used together.

Pick up dog poop promptly

This is one of the easiest habits to build.

Remove feces from your yard and other areas where your dog spends time as soon as possible. Cornell specifically recommends prompt feces removal to reduce contamination with hookworm eggs and larvae.

Don’t leave piles sitting in the yard for days.

Keep your dog on appropriate parasite prevention

Regular parasite prevention can reduce the risk of hookworm infection.

Some monthly heartworm preventives also contain ingredients that control hookworms. Your veterinarian can help determine which product fits your dog’s age, lifestyle, and parasite risks.

If your dog already takes a monthly preventive, check exactly which parasites it covers.

Prevent scavenging and hunting

Dogs that eat rodents or other small animals have another possible route of exposure.

Management and training can help reduce this behavior, particularly for dogs that spend a lot of time outdoors.

Keep puppies on schedule

Puppies need early parasite control.

Cornell recommends treating puppies beginning at two weeks of age and repeating treatment every two weeks until around eight weeks, followed by monthly prevention.

Your veterinarian may adjust the schedule depending on the puppy and the medication being used.

Treat nursing mothers appropriately

A nursing female can pass hookworm larvae to her puppies.

Keeping the mother and puppies on an appropriate veterinary-directed parasite-control plan helps reduce this route of infection.

Can Humans Get Hookworms From Dogs?

Yes, some canine hookworm species can affect people.

In humans, hookworm larvae can penetrate the skin and cause cutaneous larva migrans, an itchy skin condition often associated with walking barefoot on contaminated soil or sand.

Children can be particularly vulnerable when they play in contaminated areas.

Simple precautions make a difference:

• Pick up dog feces promptly.
• Wash your hands after handling pet waste.
• Wear shoes in areas that may be contaminated.
• Keep children away from potentially contaminated soil or sand.
• Cover outdoor sandboxes when they aren’t being used.
• Keep pets on appropriate parasite prevention.

You don’t need to panic because your dog has hookworms. You do need good hygiene and sensible parasite control.

When Should You Take Your Dog to the Vet?

Call your veterinarian if you suspect hookworms, particularly when your dog is a puppy.

Seek prompt veterinary care if you notice:

• Pale or white-looking gums
• Severe weakness
• Collapse
• Bloody or black, tarry stool
• Persistent vomiting or diarrhea
• Rapid weight loss
• A puppy that isn’t growing normally
• Significant lethargy
• Dehydration

Severe hookworm infections can cause dangerous anemia in puppies and, in rare cases, can be fatal.

Trust me on this one: a pale, weak puppy is not a “wait until tomorrow” situation.

Hookworms vs. Roundworms in Dogs

Hookworms and roundworms are both intestinal parasites, but they behave differently.

Hookworms attach to the intestinal wall and feed on blood. That’s why anemia and dark, bloody stool are major concerns.

Roundworms live in the intestine and compete for nutrients. They are more commonly associated with a pot-bellied appearance, poor growth, and visible spaghetti-like worms in stool or vomit.

The treatments can also differ, so seeing a veterinarian for proper identification matters.

If you’re trying to understand your dog’s overall deworming schedule, our Dog Deworming Guide covers the broader parasite picture.

Frequently Asked Questions

Protecting Your Dog From Hookworms Starts With the Routine

Hookworms are easy to underestimate because the worms themselves are tiny.

The effects can be much bigger, especially in puppies. Blood loss, anemia, poor growth, and severe weakness can develop when infections are heavy.

The practical approach is simple: keep your dog on an appropriate parasite-prevention plan, pick up feces promptly, limit contact with contaminated soil, and take symptoms seriously.

If your puppy has pale gums, weakness, diarrhea, or poor growth, contact your veterinarian rather than waiting to see a worm in the stool. Hookworms can be present before a fecal test becomes positive, and young puppies can become seriously ill quickly.

Give it time, follow the treatment schedule, and stay consistent with prevention. That’s how you break the hookworm cycle.

Resource Consulted

Hookworms in Dogs — Cornell University College of Veterinary Medicine