The symptoms and effects of worms varies with the type of worm and degree of infestation.
Digestive tract worms can trigger symptoms ranging from no symptoms (asymptomatic) to dogs that show symptoms such as weight loss and diarrhea. All four digestive tract worms can be spread from one dog to another.
There is also a risk of hookworms and roundworms being transmitted to humans. Most puppies are born with roundworms from the mother while adult dogs contract worms from feces. The one exception is the tapeworm which is spread through an ingested flea. Each type of parasite (another name for worms) has its own characteristics which can be helpful in worm identification.
Most Common Types of Intestinal Dog Worms
As mentioned, there are four common dog worms types as indicated below:
Roundworms (also called Nematodes)
Dog roundworms are the most common type of worms in dogs. The worms are named after their appearance, which in an adult is like a piece of spaghetti. The worm is spread from dog to dog through the ingestion of contaminated feces, or from a pregnant mother through the placenta to the puppy, resulting in a case of puppy worms.
Roundworms can be transmitted from dogs to humans, which is especially a concern for children.
Dog Whipworms are less common than hookworms or roundworms. They are also transmitted by ingesting contaminated feces and affects both puppies and adult dogs. The parasite can cause severe health problems. The worms attach to a dog's intestinal lining and feed on the host's blood. As the worms multiply in the intestine, they can deplete the blood supply, causing a condition called canine anemia. In puppies in particular, advanced cases can be life threatening.
Dog hookworms are also one of the more common dog worms types. The worm is transmitted via ingested contaminated dog feces are through contact with an open wound or skin crack. Hookworms in dogs infect adults more often, and are less common in puppies, the reverse of what is true for roundworms.
Dog tapeworms (cestodes, Dipylidium) are common. It is not transmitted through feces like other worms in dogs, but instead is passed through the ingestion of a flea, which carries the immature tapeworm. These dog worms take their name from an appearance, with the worms measuring from 4 to 28 inches in length. As the worm grows in the intestines, segments (proglottids) break off. The infection causes no dog worm symptoms and often goes undetected until the owner notices the small, dried up segments migrating out of the rectum. In advanced cases, there could be some weight loss. These worm segments become caught in the fur surrounding the anus or on the outside of fresh feces and can even be seen crawling on the surface. When the worm segments dry out, it leaves behind small hard yellow eggs that can also be stuck to the dog's fur around the anus.
Tapeworm (dog worms types) is diagnosed during a fecal exam performed in your veterinarian's office. There is minimal risk of the worm being transmitted to humans, although it is possible if a person, particularly a child swallows a flea.
Dog Flatworms (also called Trematodes or Flukes): These dog worms types often hook themselves to your dog in their intestines, lungs and liver. They are also passed when a dog ingests infected feces ,and in infected snails and frogs.
Dog Heartworm: Heartworm disease in dogs (Dirofilaira immitis) occurs when worms grow in and around the heart muscle. The disease is spread when an infected mosquito bites a dog. This is one of the most alarming dog worms types since in advanced stages it is life threatening.
Most infected dogs are asymptomatic for months or years, with heart damage slowing increasing over time. Symptoms of dog heartworm includes moderate to severe coughing, particularly after exercise or when excited. In later stages of the disease the abdomen and legs will swell from fluid accumulation as the right side of the heart suffers from developing congestive failure. Other symptoms when a severe case of the disease is present include difficulty breathing (dyspnea). It is rare for a dog to suddenly die from the disorder. Dog heartworm (dog worms types) infection is diagnosed with a blood test. The test can also indicate the severity of the disease which would point to a specific course of treatment. x-rays can also help to confirm the severity of the disease.
Source: Dr. Richard Wescott/Washington State University
It is difficult to treat heartworm in dogs. Treatment can be risky since killing worms that are already in the arteries and heart can be dangerous. Cases are usually classified from high risk to low risk based on the chance of complications that result from treatment. Low risk or class 1 and 2 dog heartworm cases are characterized by having no symptoms and normal heart x-rays. High risk or class 3, 4, 5 canine heartworm patients are already showing symptoms such as coughing and abdominal swelling.
Dog heart worm treatment
involves symptomatic therapy
to improve heart function and circulation. It is also used to prepare
dogs that are treated with an adulticide that kills the heartworm or
for surgical removal. Most vets will recommend restricted
exercise and cage rest as a way of improving blood circulation.
Anti-inflammatory drugs such as glucocorticosterids (prednisolone) can
also help to control pulmonary inflammation and thromboembolism.
The most commonly used dog heartworm treatment is the
Immiticide (melarsomine hydrochloride) which is injected into the back
muscles of dogs suffering from class 1 - 3 heartworm. A
preventative is only used after the heart has been cleared of all
Luckily, humans cannot be infected by heartworm.
Dog Ringworm (not a worm, a fungal infection)
Note that ringworm is not due to worms, but a skin fungus. It's name is based on an appearance on the skin that looks like a worm.
Symptoms and Diagnosis
Many dog owners believe that dogs with normal feces do not have worms. This is not the case. It is also rare for owners to see worms in the dog stool. Dog worms will infrequently have a loose stool or diarrhea. There is nothing about the appearance or consistency of a stool that will indicate if a dog has worms. The reason is that dog worms may remain in the dog while the only thing that is shed are microscopic eggs that cannot be seen with the naked eye.
Many dogs with worms will suffer from conditions such as malabsorption or mild malnutrition, which results in weight loss, even though the dog appears to be eating normally. The loss of nutrients due to malnutrition or malabsorption may also cause a loss of quality in the dog's hair coat. The coat may appear to be unkempt or dull.
Most of the time, a dog with worms is diagnosed by a veterinarian after studying feces under a microscope.
Most veterinarians will check dogs on a regular basis for the different dog worms types by looking for worms in the stool.
Treatment for intestinal parasites generally consists of a broad-spectrum dewormer such as fenbendazole (Panacur®), with the addition of praziquantel (Droncit® or Dog Worms®) if tapeworms are also present. Treatment for dog heartworm is indicated above.
If you dog frequently has a problem with parasites such as the many dog worms types, a natural dietary supplement is worth a try. PetAlive makes a supplement designed to naturally expel internal parasites like Heartworm, Roundworm and Tape Worm. Check with your veterinarian.
Dog Worms and Humans
Most dog worms types are species specific. However, it is possible for humans to get intestinal worms from your dog. The problem is more common in children. For example, children that crawl on the ground or play in sandboxes can ingest the eggs that result in worms.
Hookworms can burrow through human skin and are often found in gulf coast states. In a human a hookworm leaves red spots on the skin that are in a trail (caused by the larvae).
Other dog worms types such as whipworms do not live in humans. The most common type of worms in humans, pinworms, are not found in dogs and cats.
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References for Dog Worms Types
IVIS – International Veterinary Information Service
Atkins, Clarke E. DVM, Canine Heartworm Disease: Prevention and Treatment
Heartworm Disease in Dogs; Venco, Luigi