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Dog Worms

Veterinarian Reviewed on March 29, 2014 by Dr. Janice Huntingford

Dog Worms (Canine Parasites)

Signs and Symptoms

Worms are internal parasites that commonly infect dogs, causing a myriad of problems. These pesky parasites drain nutrients from your pet’s blood, adversely affecting its general health. While dog worm infections are common and can be quite easily controlled and cured, some of these parasites can be dangerous and when certain types of these infections are left untreated, the results can be deadly. Therefore, it’s good to have an idea of what to keep an eye out for so that you can ensure prompt treatment for your dog if he or she indeed does become a victim of parasitic worms.

As there are a number of different worms that will infect canines, the symptoms and warning signs of such an infection may not always be the same in every case. However, there are certain signs that are frequently exhibited by dogs that are plagued by worms. Some pets who are infected with worms suffer from malnutrition and anemia. Dogs with an especially large amount of worms in their system may take on an unhealthy, malnourished appearance. Also, dogs that become anemic as a result of such an infection often have a rapid heart rate. Sometimes these canines will also develop a swollen, potbelly. This last sign is particularly characteristic of puppies suffering from internal parasites. Puppies are also more prone to experiencing changes in their coats, with their fur becoming dry, coarse, and dull. Sometimes the worms can be seen in the stool or around the anus. They can appear in puppies and adult dogs like small white grains of rice. You may notice them in the feces, or in places that the dog frequents. (bedding, carpets, etc.)

Weight loss is also symptomatic of a worm infestation. Lethargy and fatigue are also common. Canine worms can also cause abdominal pain and a discharge of mucus from the eyes. It’s also important to watch out for diarrhea, vomiting, and unusually dark feces. A hot, dry nose, pale gums, and bad breath can also be signs that your pet is being troubled by internal parasites. Unusual, frequent changes in appetite and disturbed sleep are also warning signs to watch for. Since worm infections can be damaging to your dog’s health and can cause a great deal of misery and discomfort, it’s important to alert your veterinarian as soon as you notice your pet displaying any of the above signs and symptoms.


When checking your dog for worms, a veterinarian will look for the above mentioned signs and symptoms. They will also want to know about the behaviors and symptoms that you have observed at home. In addition, it is most likely that some form of fecal testing will be performed. There are a number of different fecal tests that can be used to confirm the presence of worms in a dog, and different tests are better at detecting certain types of worms than others. The fecal tests commonly employed by veterinarians under these circumstances include direct smears, fecal floats, fecal cultures, and Baermann tests.

For all of these tests, fresh feces that are still close to body temperature and that have not been on the ground for very long must be used. Direct smears are used to identify giardia trophozites while the Baermann technique can reveal the presence of aelurostrongylus. In the case of fecal floats, a centrifuge is used, and this test can be helpful with confirming the presence of the eggs of certain parasites. A fecal culture, on the other hand, is used to look for the presence of pathogenic bacteria like salmonella, which could also cause your pet to display a variety of unsettling symptoms.

Although it is likely that your veterinarian will employ one or more of these tests, much of the time the results will turn up negative even when your dog is suffering from worms. In fact, approximately seventy-five percent of fecal samples taken from dogs infected with internal parasites will not actually confirm the presence of these worms. As a result, veterinarians will often prescribe a deworming treatment even with negative test results. This is done because infections of dog worms are so common and it can be dangerous and troublesome for your pet if this condition is left untreated.


Whipworm Egg

Worms are internal parasites that can infest your dog and cause a variety of problems. The four most common types of worm that affect dogs are roundworms, tapeworms, hookworms, and whipworms. Roundworms, hookworms, and whipworms are all classified as round-shaped worms, also known as nematodes. In appearance, these parasites look similar to common angle worms, except for their coloring which is much lighter. Posing a particularly common problem in puppies, nematodes infest a dog’s small intestines. Here, the worms attach themselves to the walls of the intestines and feed upon the canine’s blood, draining your dog of both blood and nutrients. Moreover, if these worms coil together in a mass, they can potentially cause a dangerous obstruction. Sometimes nematodes will stray away from the small intestine, either moving into the dog’s stomach or passing through the bowels.

Cestodes, on the other hand, are flat-shaped worms and this is the category that tapeworms fall under. These worms will infest a dog’s intestines as well, but they will also infect other organs such as the liver. Similar to nematodes, cestodes attach themselves to organ walls and use your pet’s blood for food, absorbing it through their skin or integument. Again, this reduces the amount of nutrients that your dog is able to absorb. While these worms tend to not pose too much of a serious threat for dogs, their presence in the intestines can cause damage, as is the case with nematodes. While certain types of worms are more dangerous and troublesome than others, most will cause at least some level of discomfort and, therefore, prompt diagnosis and treatment will always be beneficial for your pet.


Unfortunately, it is very easy for dogs to contract worms, and this can happen in a variety of ways. Puppies are particularly prone to becoming infested with these parasites for a number of reasons. It is thought that puppies can even become infected before they’re even born, as worms are passed through the mother to the puppy through the placenta. In addition, after the puppy is born, it will be exposed to the worms and eggs present on the mother’s coat and body as well as in the surrounding environment.

When infected dogs defecate, millions of eggs are passed out of the body along with the feces. These will then be scattered around the soil, grass, bedding, or other areas. The fact that these eggs can survive in soil and other external environments for several years makes their spread even easier. Previously uninfected dogs will become exposed to these environments, by playing in the grass or by coming in contact with the coat of an infested dog. These parasites will then gain access to the previously unaffected canine, either through ingestion or absorption through the skin. Once inside the dog’s body, the eggs will hatch and become fully grown in approximately ten days. As a result of how these parasites are typically spread, infestations are particularly common in unhygienic or communal environments. Such places include humane shelters, doggie day cares, and large kennels.


If your dog is infected with worms, it is best to treat the condition promptly in order to relieve your pet’s suffering and to avoid the contamination of your dog’s environment, which can increase the chance of reinfection. Since most puppies either already have worms at birth or contract them soon after, it’s important for them to be treated early. Also, in households with children or people with suppressed immune systems, prompt deworming is vital in order to prevent the transmission of the parasitic infection to humans.

A number of deworming products are available to help cure and control the most common types of parasite infections in dogs. While there is no deworming medication that will get rid of every type of worm, some products can effectively deal with more than one type of parasite. Typically, deworming products that combat round-shaped worms will not be effective against tapeworms, and vice versa. Therefore, more than one type of medication or product may be required if both kinds of worm are present in your dog’s system.

In addition to traditional medications, there are also some homeopathic remedies available that can help you and your dog combat an infestation of worms. Some of these products also help to prevent future infections by fortifying your dog’s system and reducing its susceptibility to such infections. Natural substances and ingredients that can be beneficial for a dog suffering from internal parasites include fennel, milk thistle, elecampane, and papaya. The positive effects that these substances can have range from paralyzing worms and dissolving their protective layers to reducing inflammation and stimulating the production of strong, healthy cells. As result, there are a number of substances and products that can help to relieve the suffering of an afflicted dog. As with treatment for any other medical condition, however, deworming should always be carried out with the advice and supervision of a veterinarian.

Suggested Products
Inulin PK for Dog Worms

Read also: Dog Laryngeal Paralysis
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Our Expert

Dr. Janice Huntingford
Janice Huntingford, DVM, has been in veterinary practice for over 30 years and has founded two veterinary clinics since receiving her Doctor of Veterinary Medicine at the Ontario Veterinary College, University of Guelph. She has studied extensively in both conventional and holistic modalities. Ask Dr. Jan

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