Parasites in Dogs
Dog Health Guides · Diseases
Dog Parasites: Fleas, Ticks, Mites, Worms, Giardia and Heartworm
If you are reading about dog parasites, your veterinarian is the best first step. This guide explains what owners commonly see and what to do next. It does not diagnose or prescribe.
Dog parasites live on the skin and coat (fleas, ticks, mites and lice) or inside the body (intestinal worms, giardia and heartworm). Some cause only itching or soft stool; others cause anemia, weight loss, serious disease, or spread to people.
The good news is that most dog parasites are preventable with a plan from your vet and regular poop tests. This guide gives you a dog parasites list, the symptoms to look for on the skin and in poop, how dogs catch them, and how dog parasites treatment and prevention work.
Important: See a vet for pale gums, weakness, bloody or black stool, a pot-bellied puppy with diarrhea, a cough with tiring on walks, or a tick-bitten dog that is limping, feverish or off food. Do not use horse, livestock or bird parasite products on dogs. Some herding breeds, such as collies, shelties and Australian shepherds and their mixes, can be sensitive to ivermectin and some other parasite medicines, so ask your vet before giving your dog any parasite product.
Dog Parasites List
Fleas
Tiny jumping insects that cause itching, flea allergy, and anemia in puppies. Fleas also spread tapeworms.
Ticks
Ticks attach to feed and can spread Lyme disease, ehrlichiosis, anaplasmosis and other infections.
Mites
Sarcoptic mange mites (very itchy, contagious), demodex mites (hair loss, often in puppies) and ear mites.
Intestinal Worms
Roundworms, hookworms, whipworms and tapeworms. See worms in dogs.
Giardia and Coccidia
Single-celled parasites that cause diarrhea. See giardia in dogs.
Heartworm
Worms spread by mosquitoes that live in the heart and lungs. See heartworm in dogs.
Dog Parasites Symptoms
On the Skin
Scratching, flea dirt, hair loss, scabs, red bumps, ticks, and dark wax in the ears. See skin problems in dogs.
In the Poop
Diarrhea, mucus, blood, worms that look like spaghetti, or rice-like segments around the bottom.
General Signs
Weight loss, a dull coat, pot belly in puppies, pale gums, low energy, and scooting.
Cough or Tiring Easily
A mild cough and tiring on walks can be signs of heartworm or migrating roundworm larvae.
How Dogs Catch Parasites
From the Environment
Worm eggs and giardia cysts live in soil, grass, puddles and poop, especially at dog parks and kennels.
From Other Animals
Fleas, mites and ticks pass between dogs, cats and wildlife. Fleas carry tapeworm, and dogs swallow them while grooming.
From Mother to Puppies
Roundworms and hookworms pass to puppies before birth and through milk, which is why puppies are dewormed early.
From Mosquitoes
Heartworm is spread only by mosquito bites.
Some Spread to People
Roundworms, hookworms, giardia, mange mites and fleas can affect people. Pick up poop promptly and wash hands, especially with children.
Dog Parasites Treatment and Prevention
A Year-Round Plan
Your vet recommends prevention for heartworm, fleas, ticks and worms based on where you live, your dog’s lifestyle, and breed.
Poop Tests
A fecal test once or twice a year, and whenever your dog has diarrhea, finds parasites you cannot see.
Heartworm Testing
A yearly heartworm blood test, even for dogs on prevention.
Treat Every Pet
Flea treatment works best when every dog and cat in the home is treated, along with bedding and the house.
What To Do Tonight
Routine
No signs, but due for prevention or a poop test: book a checkup and ask your vet for a year-round parasite plan.
See a vet
Pale gums, weakness, bloody stool, a sick puppy, a cough with tiring, or illness after a tick bite.
Related products
Heartworm Tablets for Dogs - Heartworm Prevention for Dogs
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Monthly heartworm prevention for dogs. Ask your vet for a heartworm test first and to confirm this product suits your dog. It does not treat an existing heartworm infection. Some herding breeds, such as collies, can be sensitive to ivermectin, the active ingredient, so check with your vet before use.
View product →Free shipping on orders $75+. Prices and stock update automatically. Products are listed for education; medicines are used only when a veterinarian directs care. This page does not diagnose or prescribe.
Related Dog Health Guides
Back to Dog Health Guides →Parasites in Dogs FAQ
What are the most common dog parasites?
Fleas, ticks, roundworms, hookworms, whipworms, tapeworms, giardia and, in many areas, heartworm.
What are dog parasite symptoms on the skin?
Itching, flea dirt, red bumps, scabs, hair loss, and ticks attached to the skin. Mange causes intense itching and crusts.
How do I know if my dog has giardia or worms?
Diarrhea, mucus or worms in the stool, weight loss and a pot belly in puppies are clues. A vet poop test confirms it.
What is the best dog parasites treatment?
The right product depends on the parasite, so your vet chooses it after an exam, a poop test or a heartworm test. Prevention is easier than treatment.
Can I use a horse or livestock dewormer on my dog?
No. Products made for other animals are dosed for much larger animals and can poison dogs, especially herding breeds. Use only what your vet prescribes.
Is this parasites in dogs guide a substitute for a vet visit?
No. It is educational only. Your veterinarian should examine your dog and guide any diagnosis and treatment.
Can I work out a medicine dose from this page?
No. Never work out doses from product strengths, other pets’ medicines or internet pages. The right medicine and dose depend on your dog’s weight, age, breed, health and other medicines, so they must come from your veterinarian.