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canine health problems
Group of dogs at park

The essentials

  • Intestinal parasites are common in dogs — Your vet can help you determine which type of parasite your pup is dealing with and provide treatment.
  • Treatments range from pills to injections — The duration of your dog’s treatment will depend on the severity of their infection and how well they respond to medication.
  • Prevention is key — Easy-to-follow measures help keep intestinal parasites at bay so they don’t become a problem to begin with.

Believe it or not, many organisms live rent-free inside your dog. Some provide health benefits, such as helping to break down food or regulate chemical balances. Others have a harmful impact on your dog’s health. These organisms are called parasites, and according to the CDC, they live off and survive at the expense of their hosts, either by stealing their food or feeding on them directly.

Places where your pup is most at risk

Anywhere your pup comes into contact with other dogs poses a risk. In fact, communal settings tend to increase a pup’s chance of contracting a whole host of diseases, including parvo, distemper, flea-borne illnesses, and more. That said, a few of the most common places your pup might pick up an intestinal parasite are listed below.

The dog park

Dog parks are major contributors to the spread of parasites since dogs at these parks drink from the same water dishes and play on the same fecal-ridden soil. In fact, a 2019 study found that 85% of the parks they sampled had at least one infected dog. And, at least in the U.S., one in five dogs at any given dog park are likely infected with gastrointestinal parasites.

Doggie daycare and boarding facilities

Most boarding facilities have a rule against sending your pup to daycare if they’re experiencing diarrhea — and for good reason. It doesn’t take much for one dog’s tummy troubles to spread to another. Just one lick of contaminated fur (or fecal matter) is enough to infect your pup with their friend’s parasite. If your dog’s daycare doesn’t have a policy around parasite prevention, take that as your warning sign to find a location that does.

Competitions or training classes

Unfortunately, pups can pick up more than just new skills at training classes and competitions. While there’s no guaranteed way to ensure your pup won’t get an intestinal parasite from their local training class, there are a few best practices to try. Start by staying up to date on your pup’s monthly heartworm treatments and keeping a close eye on your pup when they’re around other dogs.

Animal shelters

A recent study revealed that dogs in animal shelters are far more likely to have an intestinal parasite than dogs that live in private homes. If you just picked up a new pet from your local shelter, ask your vet about how to make sure your dog’s tummy remains in tip-top shape. Just to be safe, your vet will likely recommend a fecal test to rule out any parasites.

Common intestinal parasites in dogs

Roundworms. Whether you’ve noticed them or not, chances are high your dog has been exposed to roundworms at some point in their life. These white, spaghetti-like worms can travel through a dog’s body but typically make their home in their host’s large intestine. Puppies are more likely than dogs of other ages to get roundworms because they can contract it in the womb or from their mother’s milk. But, adult dogs can also contract roundworms by being exposed to an infected animal’s feces or vomit, or by eating another animal with roundworms, like a mouse.

Hookworms. As their name implies, hookworms “hook” themselves to the interior lining of a canine’s intestines. There, they feed on the dog’s blood and lay eggs that get passed into the digestive tract and out the body. The resulting larvae then embed themselves in the soil and wait to hitch a ride on another dog’s paws, where they penetrate the skin or are ingested. According to the Companion Animal Parasite Council (CAPC), puppies are particularly vulnerable to hookworms. The bloodsucking worms can cause blood loss in pups, which can stunt their growth.

Whipworms. Whipworms are similar to hookworms in that they attach themselves to the inner lining of the cecum and large intestine at the point where the large and small intestines meet. Some dogs with whipworm don’t display symptoms, making them difficult to diagnose. They’re also so tiny that it’s difficult to spot them in stool. But the CAPC notes that, as the worms multiply, a dog’s colon and cecum become inflamed, resulting in bloody stool, diarrhea, or anemia. If left untreated, severe infections can be fatal.

Tapeworms. Tapeworms get their namesake from their flat shape and segmented anatomy. According to the CAPC, each tapeworm segment contains reproductive organs, segments of which break off as dogs pass waste. The small segments are usually visible to the naked eye in the feces and may resemble small white seeds or individual grains of rice. Hunting dogs and dogs that live in rural areas are most likely to be exposed since tapeworms require an intermediate host like fleas.

Heartworms. Though heartworms are an internal parasite, they’re ubiquitous enough to mention. These worms live in the hearts and lungs of their hosts and can grow up to 16 inches long. Contact your vet if your dog experiences symptoms like fatigue, shortness of breath, and coughing, which are all signs of heartworm. If left untreated in dogs, this type of parasitic infection can be fatal.

Coccidia. Unlike the aforementioned worm parasites, coccidia are actually single-celled organisms. But like their worm counterparts, this parasite can enter your dog’s body when they lick dirt or consume feces. Coccidia infestations occur in the intestines but are generally not very severe. Some dogs have few symptoms other than diarrhea. However, VCA Animal Hospitals states that for puppies or vulnerable adult dogs, infection from coccidia (coccidiosis) may cause severe watery diarrhea, dehydration, abdominal distress, vomiting, and in severe cases, death.

Giardia. Giardia is another single-celled infectious organism. According to VCA, they enter their host’s body when that animal consumes contaminated water or fecal matter. They have two forms: a “feeding” form and a cyst form, the latter of which protects them from the elements when they’re outside their host.

Intestinal flukes. While not as common as other intestinal parasites, dogs can be exposed to these small, oval-shaped organisms. One common way this can happen is by eating raw or improperly prepared fish. The Merck Veterinary Manual notes that they travel through their host’s body and settle in the small intestine, where they can cause intestinal damage, weight loss, vomiting, and diarrhea.

Common parasites in dogs

How do dogs get intestinal parasites?

Intestinal parasites have many ways in which they try to infect your pup. Keep an eye out for the following to minimize your dog’s chance of exposure.

The food they eat. One of the best vehicles for intestinal parasites to enter the body is through raw food — be it meat, vegetables, grains, untreated water, or more. For this reason, the United States Department of Agriculture (USDA) recommends steering clear of raw food diets. Any food your dog eats should be thoroughly prepared and certified for their consumption. Part of good food preparation also means having clean dishes and bowls to eat out of and keeping food far away from fecal waste.

Interacting with other dogs. We love when our pups get along with other dogs. And so do parasites! That’s because it’s much easier for parasites to transfer eggs to additional hosts, whether through direct or indirect exposure.

Born with them. Some intestinal parasites in pregnant dogs can travel from the intestines to the womb. These parasites then transfer to still-developing puppies in utero. Additionally, once the dogs are born, some parasites can be transferred to puppies via their mother’s milk. Because of their fragile immune systems, young pets are particularly susceptible to parasites of the digestive system.

Other pests and animals. Fleas, ticks, rodents, and other animals can also serve as intermediary hosts to parasites. Parasites can break free from their initial hosts and make their way to the intestines of dogs who ingest infected fleas or ticks. Additionally, animal feces may contain parasites. If your dog walks on or ingests fecal matter, any potential parasites within it have a fast track to your pup’s intestines.

Signs your pup has an intestinal parasite 

Most symptoms of intestinal parasites are fairly easy to identify. Some of the most common signs include the following:

  • Loose stool or diarrhea
  • Blood in stool
  • Weight loss
  • Inability to gain weight
  • Dull, coarse coat
  • Weakness and fatigue
  • Visible worms in feces

If left untreated, complications can arise. Severe infections can even result in death.

👉 Some dog parasites, such as roundworms, hookworms, and giardia, can also infect humans. The symptoms in humans are typically the same as they are in pups.

Diagnosing parasites in pups

Most diagnoses occur with fecal testing. Your dog’s vet may also conduct a special test that allows them to determine if there are parasitic eggs in your dog’s stool.

On very rare occasions, vets will need to conduct an endoscopy through the mouth or a colonoscopy through the rectum to better identify parasites.

Treating intestinal parasites in dogs

Some of the most common parasites found in dogs are those that live in the intestines. But fear not — just because you can’t see them, doesn’t mean you can’t treat them.

Some dogs react better to certain forms of treatment than others, but common options include oral medicines, injections, and topical treatments. Treatment plans often depend on factors such as your dog’s age, weight, reaction to treatment, and the severity of their infection.

Always consult your vet for treatment if you notice any of the symptoms listed above. Your vet will prescribe safe and effective drugs to kill any parasites your dog has.

👉 Do not attempt home remedies for intestinal parasites, as these will only exacerbate symptoms. Intestinal parasites are stubborn organisms that only specific drugs can kill.

Type of parasite Common Treatment Drugs Form
Roundworms (Toxocara cati, Toxascaris leonina) fenbendazole, milbemycin oxime, moxidectin, piperazine, pyrantel Oral, topical
Hookworms (Ancylostoma caninum) fenbendazole, moxidectin, pyrantel, milbemycin oxime Oral
Tapeworms (Dipylidium caninum, Taenia) praziquantel Oral, injection, topical
Whipworms (Trichuris vulpis) febantel, fenbendazole, milbemycin oxime, moxidectin, oxantel Oral, topical
Coccidia (single-celled organisms) sulfadimethoxine Oral
Giardia (single-celled organisms) fenbendazole (sometimes combined with metronidazole) Oral

Prevention is the best medicine

While treatment for intestinal parasites is effective, no dog parent wants to worry about their pup experiencing discomfort or getting sick. And your pup certainly doesn’t want to experience symptoms either. Fortunately, with a little care and maintenance, most intestinal parasites can be stopped before they have a chance to harm your pet. For pet owners hoping to prevent them in the first place, look to the following tips:

Keep up with regular exams — Being a good pet parent means keeping your dog healthy. As such, their health regimen should include regular exams. Once or twice a year, your vet may want to take (or have you bring in) stool samples. This is a normal process and helps to identify any parasites that could be in your dog’s digestive system.

Clean up after your pet — Responsible pet parents know that cleaning up after their dog is an essential step when it comes to preventing the spread of parasites in feces. Keeping your dog’s feeding, drinking, sleeping, and play areas clean will also help prevent accidental ingestion or exposure to any parasites that may have been tracked into the house. It’s a good practice for you and your dog and helps keep other dogs healthy, too.

Maintain good hygiene — Similarly, keeping your dog properly cleaned and groomed will help to eliminate parasites that linger on their paws, fur, mouth, or around their anus. That doesn’t mean you have to bathe your dog every day (doing so can actually dry out their skin). Instead, consider purchasing disposable, pet-friendly cleaning wipes for a nice daily cleaning session. Provide a treat or two and your dog will come to love the extra attention.

Avoid raw food diets — You might think it’s a good idea to feed your dog the freshest food source possible, which would be raw food, right? Unfortunately, that’s simply not the case, and any anecdotal rewards are outweighed by the risks. The American Veterinary Medical Association opposes feeding your dog raw food because of the risk of exposure (for them and you) to dangerous bacteria, parasites, and other microorganisms that can cause serious harm. You can still serve fresh food in the form of kibble and cooked food that’s been nutritionally fortified to suit your dog’s dietary needs.

👉 Read our guide for must-know doggie food tips and a breakdown of the best foods to feed Fido.

Know what’s near you — Dogs are keen on their surroundings, and you should be, too. Knowing which parasites are in your geographic region can help keep you informed. CAPC has a useful parasite map that you can use to identify common parasites where you live.

Frequently asked questions

What are the symptoms of parasites in dogs?

Parasites in dogs can cause a multitude of symptoms. Intestinal parasites can cause loose stool, bloody diarrhea, weight loss, the inability to put on weight, stunted growth, dull fur, malnutrition, and more.

How do you get rid of intestinal parasites in dogs?

Intestinal parasites can be treated with veterinarian-prescribed drugs. The type, form, and dosage depend on the severity of your dog’s infection, as well as other factors like weight and age.

What are the most common intestinal parasites in dogs?

The most common intestinal parasites in dogs are roundworms, tapeworms, whipworms, hookworms, and single-celled protozoa such as coccidia and giardia.

What do parasites look like?

In their adult form, many parasitic worms look like thin spaghetti noodles and are often white or pale to light tan in color. In the larval stage, they are much smaller and not dissimilar in size to a seed or grain of rice. Single-celled parasites such as coccidia or giardia can’t be seen without special equipment, such as a microscope.

Do parasites in dogs go away on their own?

Some intestinal parasites are asymptomatic at first but can result in more severe symptoms over time. And even if symptoms appear to pass, many parasites can live dormant as cysts in your dog’s tissue for months or even years. Almost all parasitic infections in dogs require veterinary treatment.

What medicines kill parasites in dogs?

Many types of medications can kill intestinal parasites in dogs. Fenbendazole, moxidectin, and milbemycin oxime are a few common prescription options.