Types of Worms in Dogs

Types of Worms in Dogs


Types of Worms in Dogs: Diagnoses and Treatment Options

Worms are a common ailment for dogs of all ages. Whether you’re talking about a rescue pup fresh in from the shelter or a purebred dog from a reputable breeder, any dog can develop some form of worm-related infection and almost all do at some point in their lifetimes. There are several types of worms that attack different parts of a dog’s body; some worms are easy to deal with and pose no serious health risks while others can be potentially fatal.

Protect your pup and keep him in good health by learning about the five most common worms found in dogs including common symptoms and treatment options. As will all health problems, a professional vet diagnosis is mandatory and treatment is most effective when the issue is caught early.


Heartworm disease is an extremely serious condition caused by worms that live in the arteries of your dog’s lungs and heart. A heartworm infection is potentially fatal even with treatment; dogs that contract heartworm and are not treated will almost certainly die from complications caused by the infection. Heartworm is a threat to dogs in all 50 states but is less common where the weather is cold, as the worm is spread via mosquito bites.


Your dog may not show any immediate signs of heartworm infection. In fact, it can take several months or even years for an infection to reach the point of causing symptoms. Dogs with progressed heartworm infections may have a persistent cough, lethargic movements, or appetite loss and are quick to fatigue during walks or exercise.

The only way to successfully catch a heartworm infection before your dog becomes symptomatic is via a trip to the vet. The disease is commonly spotted through blood tests, but in some cases can be confirmed with an ultrasound.

Treatment and Prevention

The best course of action for heartworms is prevention. Heartworm prevention medication is available from your veterinarian and will stop your dog from becoming infected even if he’s bitten by a carrier mosquito. Options include monthly tablets, topical creams, or a six-month shot. It’s is vital to understand this key point about heartworm: Heartworm is easily preventable but extremely expensive and complicated to repair. Some dogs do not survive treatment and even those that do require weeks of recovery time. When it comes to heartworm, take no chances and ensure your dog is always on a preventative.


Roundworms are nasty little parasites that live in your dog’s intestines and survive on partially digested food. There are two primary types of roundworm, one being particularly dangerous as it is transferrable to humans and causes a more serious infection. Both types of roundworm are easily treated once a diagnosis is made.


Serious roundworm infections may present in a swelled or distended belly. In extreme cases worms can cause abdominal ruptures. Your dog may lose weight, cough, act lethargic, or have abnormal stool. If you suspect your dog may have roundworms it is vital that you bring him to your veterinarian for a diagnosis, as different types of worms and illnesses have similar symptoms. Roundworms can be diagnosed through a fecal swab.

Treatment and Prevention

Dogs contract roundworms by eating or drinking infected food, water, feces, or vomit. Additionally, young puppies can contract the disease by nursing from a mother dog that is infected with roundworms. There is no preventative medicine for stopping a roundworm infection, but supervising your dog’s eating and drinking habits to ensure he only consumes clean food and water can help.

Roundworm treatment involves giving your dog prescribed medicine designed to kill the roundworms present in his body. Dead roundworms are usually passed with feces; however, surgery may be necessary in extreme cases to remove remaining roundworm matter (roundworms are quite large and can be present in very high numbers). A follow-up vet appointment is necessary to verify that all roundworms have been eliminated.


Tapeworms are another form of intestinal worm that take up residence in a dog’s small intestine and feed off partially digested food items. Tapeworms are transmittable to humans and can cause grave damage to a dog’s body if left untreated. Generally speaking, the sooner you recognize and treat a tapeworm infection, the better the prognosis for the afflicted animal.


Tapeworms are one of the easier worms to spot in dogs as a tapeworm infection comes with some obvious exterior signs. If you notice white pieces of worm in your dog’s feces, your dog most likely is suffering from tapeworms. Tapeworms can also be seen under the dog’s tail in some cases. Additionally, if your dog constantly bites at his rear or drags his butt on the carpet, it’s possible he’s dealing with a tapeworm infection.

Treatment and Prevention

Your veterinarian can provide you with a positive tapeworm diagnosis by checking your dog’s feces. Once the diagnosis is set, treating tapeworms requires either oral medication or a quick shot. Tapeworms, if caught early, pose no lasting threat to your dog and will be killed off as long as you continue to treat him until the recommended treatment period ends. Tapeworms are passed on by fleas — keeping your dog on a flea preventative can help stop a tapeworm infection before it begins.


Hookworms are an extremely dangerous intestinal parasite that survive by leeching blood from your dog’s body. An untreated hookworm infestation can be fatal for your dog and hookworms are especially dangerous for puppies. As with most health ailments, spotting hookworms early gives you a better shot at avoiding long-term health problems and getting your pup back to his normal happy self.


Hookworms cause severe damage to your dog’s small intestine. The bites they create continue to bleed even after the hookworm is done feeding; over time this can cause your dog to develop anemia, a poor appetite, and an overall unhealthy appearance. Other hookworm symptoms include pale lips, ears, and nostrils. It is possible for hookworms to spread into a dog’s lungs — dogs experiencing this will cough and have unusual stool. Hookworm infections are quite common in puppies.

Treatment and Prevention

Unlike tapeworms, you cannot easily spot hookworms in your dog’s poop. Instead, the presence of hookworms must be verified by a veterinarian using a microscope. Treatment of hookworms is similar to treatment of other intestinal infections; medication must be administered that will kill the worms and allow the dog to pass them. Your vet may recommend vitamin supplements depending on the severity of the infection. Do note that serious hookworm infections can result in sudden death even if you have already begun to treat the dog. Hookworm larvae can be ingested, absorbed through the skin, or passed through a mother’s milk.


Whipworms are yet another intestinal parasite that make their homes in your dog’s large intestine. They are extremely dangerous and bring numerous debilitating side-effects. Whipworm infections can be treated much in the same way as other worm infections, but whipworms are slightly more resilient and require a deeper training protocol (this is especially true if the infection has been left to worsen).


Dogs suffering from whipworms will often have bloody or watery diarrhea. They’ll lose weight, act fatigued, and generally seem like they’re not feeling well. Bloody diarrhea should always result in a trip to the vet — even if whipworms are not the issue, bloody diarrhea is often a hint at serious puppy health problems.

Treatment and Prevention

Whipworms are acquired when dogs ingest their eggs. There’s no surefire method of preventing this from occurring. Your veterinarian can confirm the presence of whipworms by checking your dog’s stool. This is not a test you can perform at home, unfortunately, and requires specialized veterinary equipment. Treatment from there follows the same general pattern as treatment for other worms. You’ll need to feed your dog medicine that kills the whipworms and their larvae and you’ll need to do so until you hit the end of the recommended treatment plan. Whipworms usually require two check-ups and multiple treatments to be completely eradicated.

The bad news about worms in dogs is that they’re quite common and it’s very likely you’ll end up dealing with one type of worm or another over the course of your pup’s lifetime. The good news, of course, is that the most common worm infestations are easily treated and have no long-term side effects (assuming you catch them early). The best course of action is keeping your dog on the proper preventatives and checking in with your vet whenever you feel as though something is not quite right.


Further Reading


About the Author: Craig Davis is VP of Vet Organics, a company which produces effective and safe natural remedies for dogs and cats.