Outline of an orange dog with a heart shaped nose Conditions

Parasites In Dogs: Types, Symptoms, Treatment, Prevention & More


Last Updated: August 5, 2023 | 6 min read | Leave a Comment

This content was reviewed by a veterinarian.

When you purchase through links on our site, we may earn a commission. Here’s how it works.

Removing a tick from dog's fur (Caption: Parasites In Dogs)

Most dogs will be plagued by some type of parasite in their lifetime. External and internal parasites can cause everything from mild itchiness to life-threatening conditions. And some parasites in dogs can even infect humans. We’ll give you an overview of the most common dog parasites, ways your pup can get them, and how to treat and prevent them.

What Are Parasites?

The Centers For Disease Control and Prevention defines a parasite as “an organism that lives on or in a host organism and gets its food from or at the expense of its host.” Parasites are common in dogs, but many are easy to prevent, so it’s best to be informed about how you can keep these pests at bay.

Types Of Parasites In Dogs

There are two main categories of dog parasites:

  1. External – live on the outside of the body
  2. Internal – live inside the body. Most internal parasites live in dogs’ intestines, with some exceptions — e.g., heartworms and lungworms, which infect the heart and lungs.
Ear MitesTapeworms 

How Do Dogs Get Parasites?

Dog in tall grass in the woods

Dogs can contract parasites in several different ways. One of the most common means of transmission of external parasites, such as fleas, lice, and mites, is through direct contact with an infected animal (or shared bedding, collars, etc.). Dogs pick up ticks from the woods, bushes, tall grasses, or other outdoor places.

Intestinal parasites are usually transmitted when a dog eats or licks feces, soil, grass, food, or water contaminated with the parasite’s eggs. In addition, puppies can catch roundworms and hookworms from their mother in utero or their mother’s milk when feeding. Dogs can get tapeworms from ingesting infected fleas, usually from self-grooming, and they get heartworms if they’re bitten by an infected mosquito.

Symptoms Of Parasites In Dogs

Dog itching himself on ground

The signs of parasites in dogs differ depending on the type. Many of the symptoms of external parasites are similar regardless of which bug is infecting your dog. The signs of internal infestations depend on the location of the parasites. All intestinal parasites can produce similar symptoms. But if your pup has heartworms, the symptoms will differ from external and intestinal parasites.

ExternalIntestinalHeartworms & Lungworms
Excessive scratchingDiarrheaPersistent coughing
Red, inflamed skinVomitingLabored breathing
Dry, flaky skinLoss of appetiteLethargy
Dry coatWeight lossDecreased appetite
Hair lossBloated abdomenWeight loss
Black specks in fur (flea dirt)Decreased activityBloated abdomen
Black debris in ears (mites)Scooting, itching around the anus (tapeworms) 
 Parasites in poop (tapeworms, roundworms) 
 Worms in vomit (roundworms) 
 Coughing, difficulty breathing (roundworms)* 

*Roundworm larvae can migrate to the lungs and cause respiratory symptoms, pneumonia, and heart problems in some cases. These cases are called lungworms.


Vet looking at dog's coat with magnifying glass

Most external parasites are pretty easy to diagnose because they’re usually visible on your dog’s skin or in his ears in the case of ear mites. However, mange mites that infect your dog’s skin are too small to see with the naked eye, so your vet will take skin scrapings to examine under a microscope to detect them.

In the case of intestinal parasites or lungworms, your vet will typically require a fecal sample and well as a physical examination because they can all cause gastrointestinal (GI) issues. A blood test is required to identify a heartworm infestation.

How To Get Rid Of Parasites In Dogs

Removing a tick from black fur on dog

Dog parasite treatment depends on the type your dog has. But no matter the type, early detection and treatment are crucial to avoid an infestation of parasites. Severe health problems can result from untreated ticks, heartworms, lungworms, and intestinal parasites.

Dogs not treated for parasites are at high risk of anemia, dehydration, or secondary internal or skin infections. If you suspect any parasite, you should consult your vet to get your pup’s proper diagnosis and treatment. 

External Parasites

To kill fleas, ticks, and lice, you may want to consider using a spot-on treatment, like Frontline or Advantage, which will kill fleas and their eggs, ticks, and lice (but not lice eggs) directly on your dog. You’ll also want to treat your home with an insecticide spray. For ticks, it’s important to properly remove any ticks as soon as you spot them from their fur or skin because they spread serious diseases to dogs, such as Lyme disease.

If your dog has mange mites, your vet will prescribe the best medication to kill them. In some cases, you can use a medicated antiparasitic shampoo for dogs to help relieve symptoms from external parasitic infections. For ear mites, your vet may prescribe a topical medication, like Revolution, that you apply to the skin on the back of your dog’s neck or between the shoulders to kill the mites.

Intestinal Parasites

Cartoon of veterinarian petting dog next to piggy bank (Caption: Start Saving Money On Vet Bills, Compare Pet Insurance Rates In Minutes; Button Text: Get My Quotes)

There is no single dog parasite medicine that can treat all GI parasites. Once your vet identifies the specific parasite, they’ll give your pup the most effective treatment. In the case of roundworms, hookworms, tapeworms, and whipworms, your vet will recommend a dewormer medication, like Panacur–C. Other oral medications that your vet can prescribe effectively kill the Coccidia and Giardia parasites.


Heartworm treatment is complex. Dogs first need to be kept confined and inactive because activity speeds up heart and lung damage. Then, depending on how far the infection has progressed, your vet may need to stabilize your pup with steroids, heartworm preventives, or antibiotics before treatment.

Next, your dog will receive a series of FDA-approved Immiticide (melarsomine) injections that kill adult heartworms, which can take 30 to 60 days. During this time and for at least 30 days after the last injection, dogs must get complete rest and remain inactive. In severe cases, surgery may be necessary to remove the worms.


Dog taking parasite medication

The good news is that there are many preventative medications you can give your dog to stave off pesky parasites.

Fleas, Ticks, Lice & Tapeworms

The best way to prevent fleas, ticks, chewing lice, and tapeworms (since dogs get tapeworms from eating infected fleas) is to use flea and tick preventative medication regularly.

Ear Mites

Zymox Ear Cleanser With Bio-Active Enzymes

Since mites feed on ear wax and oils, keeping your dog’s ears clean can help reduce the risk of a mite infestation. We recommend Zymox Cleanser With Bio-Active Enzymes or Bohdi Dog All-Natural Ear Cleanser.

Heartworms, Roundworms, Hookworms & Whipworms

Giving your dog monthly heartworm medication (oral or topical) is the best way to prevent heartworms, roundworms, hookworms, and whipworms. Some of the most commonly used heartworm preventative medications include:

Giardia And Coccidia

Unfortunately, there’s no preventative medication you can give your dog to prevent him from getting Giardia infections or coccidiosis. But there are some measures you can take to help keep these parasites away. These steps also help keep your dog protected from other intestinal parasites. 

  • Keep infected dogs away from other dogs.
  • Don’t let your dog drink from puddles, lakes, or other untreated bodies of water, especially if the water is stagnant.
  • Clean up dog poop immediately, and avoid areas where there’s a lot of dog feces on the ground.
  • If you have to board your dog, make sure the kennel practices proper hygiene and keeps its crates, runs, and yards free of feces.

Frequently Asked Questions

Here are some of the most common questions we get from our readers about dog parasites.

What Are The Most Common Puppy Parasites?

Puppies are just as susceptible as adult dogs to all of the parasites we discuss in this article. Out of all of these parasites, the most common in puppies are roundworms. Most puppies have traces of roundworms or roundworm eggs in their tissue at birth, but they can also contract roundworms from their mother’s milk. For this reason, veterinarians and breeders commonly administer dewormers to young puppies.

Do Dogs Get Worms In Their Skin?

Worms in a dog’s skin are possible but rare. For example, a roundworm species, Dracunculus insignis, can infest the tissue beneath the skin of a dog’s legs or abdomen. Signs include red ulcers on the skin’s surface and swollen, snake-like tracks under the skin. Although extremely rare, dogs can contract D. insignis from small lakes and shallow, stagnant water.

Also rare, Pelodera dermatitis is a skin infection caused by the larvae of a roundworm species called Pelodera strongyloides that invades the skin. The affected skin is red with patchy hair and may have bumps, ulcers, or pus-filled lumps. These larvae are present in decaying organic matter and on the surface of moist soil. Dogs with healthy skin aren’t usually at risk of developing an infection.

What Parasite Causes Green Poop In Dogs?

A Giardia infection in dogs can often cause chronic diarrhea with a greenish color. If you notice that your dog’s stool is green, it’s important to get veterinary attention. Giardiasis is particularly dangerous for puppies, immunocompromised dogs, and senior dogs.

Can Humans Get Parasites From Dogs?

Fleas, ticks, and lice can all transfer to humans from your dog, and they’ll bite us but not live on us. In contrast, intestinal worms can transfer from dogs to humans, especially children, and live in their bodies. See more information in the brief video below.

Shop Online To Save Money On Preventative Meds & More

Speak to your vet to get advice on the best over-the-counter preventative medications. Most vets will offer medicine for you to take home, but you can also save a lot of money by purchasing preventative parasite medicine online. You can also protect your family from backyard parasites by getting the best pooper scooper and poop bags.

The information provided through this website should not be used to diagnose or treat a health problem or disease; it is not intended to offer any legal opinion or advice or a substitute for professional safety advice or professional care. Please consult your health care provider, attorney, or product manual for professional advice. Products and services reviewed are provided by third parties; we are not responsible in any way for them, nor do we guarantee their functionality, utility, safety, or reliability. Our content is for educational purposes only.

Notify of
Inline Feedbacks
View all comments
Scroll to Top
Send this to a friend