Worms in Dogs: Diagnosis, Prevention, and Treatment

Worms in Dogs

Here’s a detailed description of worm infestations in dogs, with key takeaways for dog owners:

What are Worms?

  • Worms are parasites that live inside a dog’s body, causing disease (helminthiasis).
  • They enter through contaminated environments (soil, water) or by eating infected food/animals.
  • Worms have complex life cycles, often involving eggs, larvae, and adult stages. Some need intermediate hosts (like fleas, rodents) to fully develop.

Types of Worms

  • Nematodes (roundworms): Common types include Toxocara (can infect humans) and Hookworms (cause skin issues).
  • Cestodes (tapeworms): Include the long, scary-looking Dipylidium (from fleas) and the smaller, damaging Echinococcus.
  • Trematodes (flukes): Like Alaria, which can spread through the body, causing various illnesses.

Symptoms of Worm Infestation

  • Sudden weight loss (worms steal nutrients)
  • Lethargy (due to low energy)
  • Appetite changes (hunger OR nausea from toxins)
  • Dull, shedding coat
  • Itchy bottom (worms may crawl out)
  • Bloated belly (especially in puppies)
  • Diarrhea/Constipation
  • Pale gums (anemia)
  • Yellowish eyes/gums (liver issues)
  • Coughing, phlegm (lung involvement)
  • Vomiting (may have visible worms)
  • Skin rashes (allergic reaction)

Consequences of Ignoring Worms

  • Weakened immune system, making the dog vulnerable to other diseases.
  • Toxicity and allergies, causing further discomfort.
  • Vitamin/mineral deficiencies, impacting overall health.
  • In severe cases, worms can cause intestinal blockage, organ damage, and even death.

Diagnosis & Treatment

  • Vet visits are essential! They’ll test stool and blood samples.
  • Never self-medicate; parasite types require specific drugs.
  • Treatment often includes:
    • Pre-deworming flea/tick treatment
    • Medication on an empty stomach
    • Ensuring the dog drinks water and poops (laxatives may be needed)
    • Follow-up doses are necessary
  • Surgery may be required in extreme cases

Prevention is Key

  • Regular deworming as advised by your vet
  • No raw food (cooking kills parasites)
  • Minimize contact with stray animals
  • Regular flea/tick prevention
  • Support your dog’s immune system with a healthy diet
  • Safe walking areas, discouraging scavenging behavior
  • Limit puddle drinking/random food scavenging
  • Keep your home clean
  • Annual vet checkups are crucial

Key Takeaways

  • Worms are VERY common, but also very dangerous if left untreated.
  • Understanding the signs helps you act quickly for your dog’s health.
  • Prevention is simpler and safer than treating a severe infestation.
  • Your veterinarian is your best ally in protecting your furry friend!

What Is Worm Infestation In Dogs?

Worms enter a dog’s body from the environment. They damage organs and tissues and cause inflammatory and allergic reactions with the occurrence of helminthiasis – a disease caused by helminths. Worms go through several stages of development (development cycle): egg, larva, and adult.

To continue their race, worms must leave the host’s body and enter the external environment. Adult females lay eggs, which are released into the environment with feces, urine, and animal secretions and end up in the soil, water, plants, and surfaces, and can even be found on the animal’s fur.

To develop, helminth eggs need a favorable environment, humidity, and warmth. The egg hatches into a larva, which matures and becomes capable of infecting a dog. The dog swallows the larva, and in the dog’s body, it grows into an adult, which begins to lay eggs. This is a direct development cycle of parasites.

In some helminths, for the larval stage to appear, an egg with a larva or a larva in the environment must enter the body of another intermediary host (intermediate), sometimes there can be several of them, they can be mollusks, insects, and small rodents.

In the body of the intermediary, a larva emerges from the egg, which parasitizes organs and tissues and undergoes a series of transformations, is released into the environment, or remains in the body of the intermediate host.

A dog, eating a shellfish, a rodent, or coming into contact with waste products of an intermediate host, becomes infected with helminth larvae. In the body of a dog (in this case, the final owner), an adult individual grows from the larva and begins to reproduce. And the cycle repeats again. The presence of an intermediate link in infection with larvae is noted in the indirect development cycle of parasites.

Types of Worms:

So, what types of helminths parasitize the gastrointestinal tract? There are 4 types of them: nematodes (round), cestodes (flat), trematodes (flukes), and whipworms (whip-shaped). Let’s look at each type of parasite in more detail.


Roundworms have an elongated body, are most often white in color, and can be quite long. Most of them live in the small intestine. They have the ability to migrate throughout the body to other organs, affecting not only the dog’s intestines but also the rest of the exhausted body. They also have the ability to move into the mammary glands of a pregnant dog, from where they enter the body of the cubs with milk. Information about infection can be obtained through analysis of stool or vomit. The most popular representatives:


Another name for this is “canine roundworm”. The size of males is 5-10 cm, and females are 9-18 cm. The worms are pale yellow. They can be transmitted to humans, but they are not particularly interested in the dog’s owner’s body, it is only a temporary “transport”. However, worms do not cause any particular harm to human health (with the exception of children). In dogs, in particularly advanced cases, the intestines can rupture.


In other words – “crooked heads”. These worms are much smaller than the aforementioned Toxocaras: the female reaches 10-14 mm, and the male – 8-11 mm. The worms are reddish-brown, yellow, or white. They do not have intermediate hosts and directly enter the dog’s body through the soil. They can cause severe dermatitis, as they are able to migrate under the dog’s skin.


Tapeworms are quite frightening with their size to owners unprepared for such a spectacle. They live in the intestines and, attaching to the walls, cause severe damage to the organ and can cause ulcers. As mentioned above, their eggs are often carried by other parasites, such as fleas. The most popular representatives:

Cucumber Tapeworm Dipylidium:

This name comes from the shape of its eggs, which resemble cucumber seeds. Its size can reach 10-70 cm. It lives and reproduces in the small intestine. The carriers of its eggs are fleas. Sometimes it can be transmitted to humans.


The body length of this worm is much shorter than that of its fellows, only 3-6 mm. It can parasitize in different parts of the dog’s body. Its characteristic symptoms are bleeding from the eyes, as well as the dog eating inedible objects. It can be transmitted to humans and have a serious impact on health, but despite this, we remain intermediate hosts for it.

Flukeworms can parasitize different parts of a dog’s body. It is noteworthy that worms can exist both as a full-fledged organism and as a parasite. Let’s look at the most popular intestinal parasite.


Like all flukes, it is small in size: up to 4 mm. Most often, dogs become infected with them through bodies of water, from frogs, tadpoles, and other carriers of larvae. While worms migrate through the body, they can leave behind a number of other diseases, such as pneumonia.

The worst thing is that in the initial stages of invasion, it is impossible to understand from the symptoms whether the dog is sick or not. But after a few days, signs of bronchopneumonia begin due to inflammation left by parasites. Dogs begin to consume inedible food, become exhausted, and may even experience epileptic seizures.

Symptoms Of Worm Infestation In Dogs:

To successfully help your pet overcome the disease, it is worth knowing about the signs of helminthic infestation. What symptoms are worth paying attention to?

Sudden Weight Loss:

The most noticeable symptom is sudden weight loss. The fact is that parasites feed on the food consumed by the dog, and, as a result, the animal does not receive enough food and loses weight.


The dog becomes inactive, since energy comes from food, and the dog does not have enough nutrition.

Change In  Appetite:

A strong craving for food is justified by the constant hunger that a dog experiences when all its food is taken away by uninvited guests. The reason for the loss of interest in food may be toxic substances released by the worms, which cause nausea in the pet.

Dull, Falling out Fur:

Due to a lack of nutrients and vitamins, the dog’s hair becomes weaker.

Anal Itching:

If the infestation is advanced, the worms crawl out through the anus. The dog experiences itching in the anus area, which causes him to start rolling on his butt.

Bloated Belly:

This is especially noticeable in puppies and small breeds. When there are too many worms, they curl up into a ball and enlarge their belly.

Stool Disorders:

The dog alternates between constipation and diarrhea. The cause of constipation may be blockage of the intestinal lumen by a ball of helminths. With loose stools, the worms themselves can come out.

Pale Gums:

This is anemia, a consequence of a lack of iron, which, again, is taken from the dog by helminths.

Yellowness of Mucous Membranes:

The gums and whites of the eyes acquire an uncharacteristic yellowish tint. This is usually due to impaired bile flow and liver damage.


The dog may wheeze and cough up phlegm. This is usually associated with the introduction of worms into the lumen of the lungs.


Hiccups and belching may occur, accompanied by the dog vomiting. Sometimes with bile and traces of parasites.

Skin Rashes:

This is an allergic reaction of the body to toxic substances received. This means that eosinophils, a type of cell in the blood, are higher than normal.

Consequences Of Worm Infestation In Dogs:

No disease should be left unattended. Although helminthiasis is common, it can be devastating for pets. What can be the consequences of delaying treatment of gastrointestinal parasites or ignoring symptoms?

Weakening Of The Immune System:

This is just the beginning because weakened dogs are susceptible to other infectious diseases, which will only worsen their well-being.

Intoxication and Allergies:

The dog will begin to scratch itself a lot, and other parasites can get in through wounds on the skin against the background of reduced immunity. Intoxication will cause vomiting, diarrhea, and, as a result, poisoning and dehydration.

Lack Of Vitamins And Micro- And Macroelements:

Zinc and vitamin A are vital for dogs but are mercilessly absorbed by helminths. Zinc deficiency impairs metabolic processes, blood clotting, and wound healing. The dog may begin to have problems with fat metabolism and the functioning of internal organs.


If helminthiasis occurs, unfortunately, the dog may not survive the disease. Hematophagous worms injure internal organs and disrupt blood clotting. Intestinal obstruction can cause severe intoxication with its own waste and toxic substances from the parasites themselves. Do not ignore the symptoms described above and contact your veterinarian immediately if you suspect helminthiasis.

How to Diagnose Worms In a Dog?

If a helminthic infestation is suspected, collect samples of the dog’s feces and blood and contact a veterinary laboratory. Dogs typically become infected with roundworms and flatworms that are localized in the intestines, and a stool test may be sufficient. But if the dog is infected with heartworms (roundworms transmitted by mosquito bites), nothing will be found in the feces. Therefore, helminthological studies are usually complex.

Treatment Worm Infestation In Dogs:

Worms do not fight each other and can parasitize in different parts of the body. A dog can be infected with several types of parasites at once, and therefore treatment will be more difficult. Treatment of helminths.

Of course, if you notice worms in your pet, and even more so if your fears are confirmed, follow exclusively the veterinarian’s instructions! Never engage in self-treatment after reading articles on the Internet. Different parasites require different treatment methods and different medications. However, here are some recommendations common to drug treatment for all types of worms:

  • A few days before the start of treatment, it is worth poisoning the parasitic insects, as they are carriers of worm eggs.
  • Medicines should be given on an empty stomach to prevent the dog from vomiting.
  • Make sure your dog drinks enough.
  • Since anthelmintic drugs hit the liver hard, the dog must defecate. If this does not happen in the next few hours, it is better to give her a laxative.
    The drugs kill only adults, but the larvae remain, so after a period of time, which is worth checking with your veterinarian, you need to re-treat.
  • In particularly advanced cases (fainting, severe intoxication, convulsions), surgical intervention may be required. In such cases, it is better to leave the pet in the clinic, where it will be given proper care and freed from infestation.

Prevention Of Worm Infestation In Dogs:

Not a single dog is immune from worms, but in order to reduce the possibility of infestation to the smallest chance, preventive procedures should be carried out.

Deworm Your Dog In A Timely Manner:

As soon as you notice signs of helminthic infestation in your pet, do not delay treatment! Contact your veterinarian immediately to avoid more serious problems. It would also be useful to have preventive treatment, which should be discussed with your veterinarian as soon as you get a dog.

No To Raw Food:

There is a huge risk of finding worm eggs in raw meat and fish products. Heat-treat food before giving it to your pet.

Avoid Contact With Mongrels:

This applies not only to your dog but also to you. You can easily carry worm eggs on your clothes, and your dog can become infected not only with helminths but also with other parasites.

Carry Out Regular Treatment Against Ectoparasites:

Don’t skip quarterly deworming. Treat all animals in the house at the same time and use additional protection: a flea collar and repellent spray against mosquitoes, the intermediate hosts of helminths.

Support Your Pet’s Immunity:

Avoid stress and carefully consider your diet, for example, use Purina ONE super premium dog food.

Choose Safe Walking Routes:

Avoid places where garbage is dumped and where stray dogs and cats accumulate. Prohibit your dog from picking up from the floor, lapping from rain puddles, or eating grass. Reinforce prohibitive commands by correcting your pet using a leash. Worms can live on contaminated surfaces.

Don’t let your pet drink from puddles or eat food on the street! Dogs often become infected by eating contaminated food. Don’t let your dog pick up anything from the floor; for this purpose, it would be useful to wear a muzzle.

Limit Contact With Stray Animals:

Keep your pet away from stray dogs and cats, and stop attempts to catch a rodent or bird. Worms can live in the body of the carrier.

Keep Your Home Clean:

Carry out regular wet cleaning of the house and wash puppies and adult dogs’ paws after every walk.

Get An Annual Checkup:

If a helminthic infestation is asymptomatic, a diagnosis can only be made at an annual medical examination.


Helminths are a very serious problem that does not require delay. Despite their prevalence, these parasites are very dangerous. We advise you to monitor your pet more closely so as not to miss signs of an onset of illness.

Aapt Dubey
Aapt Dubey

Aapt Dubey, a devoted canine enthusiast and experienced dog Owner, brings boundless passion to our team. With a heart full of love for our four-legged friends, Aapt is dedicated to sharing insights on dog care, behavior, and training to make every pup's life happier and healthier at ItsAboutDog.com.

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