Worms in Dogs: The Signs of Worms in Dog Poop

Pet care & safety
Dog digging in the grass, a behavior often associated with the signs of worms in dogs.

When you welcome a pup into your home, you’re likely also inviting some internal worms. These unwelcome visitors can sneak in and stay for quite a while without anyone noticing, until they become a big problem. While a few worms typically won’t cause a big issue in adult dogs, having many worms can lead to signs such as bloody stool, weight loss, and more, especially in a puppy. So, how do dogs get worms and what should you do about them? 

Types of Worms in Dogs 

First for the intestinal crowd: 

  • Roundworms: long, tube-like critters that live in the intestines and may show themselves in your dog’s poop looking like spaghetti 

  • Hookworms: these are small but have a large appetite for their host’s blood. You may not see them in poop, so you’ll have to rely on other hookworm symptoms, which we’ll get to later. 

  • Whipworms: another long, skinny worm but with a narrowed, whip-like tail 

  • Tapeworms: a segmented worm where you’ll often see those little rice-looking segments in your dog’s poop or wriggling over the hairs under your dog’s tail 

These types of worms in dogs all look different but behave similarly. They all set up camp in the intestines where they pilfer nutrients that your dog is trying to use for themselves. Now for the important, non intestinal worm: 

  • Heartworm: the most serious type of internal worm for dogs as they can cause lasting damage, and you often won’t know they’re there until they’ve caused major issues. This one very special—and by that, I mean dangerous—worm actually lives in the heart and the large blood vessels that supply it.  

So, why are dog worms such a big deal? Well, one or two usually aren’t, but more and more of them can create such a hungry burden that a dog can’t get enough nutrients for themselves once all of the worms have had their fill. Some worms can also sneak enough blood from their host that it can lead to anemia. These issues are especially true in puppies. As for heartworms in dogs, enough of these creepy crawlies can actually cause permanent damage to the heart, blood vessels, and lungs. 

Transmission of Worms in Dogs 

Fortunately, worms don’t magically appear in dogs, but what’s not much better is the fact that they can pick them up just about anywhere. That’s right, normal day-to-day doggie stuff is how dogs get worms. Here’s how it works for most intestinal worms: 

  1. Infected animals shed worm eggs in their poop. Depending on the type of worm, this can be another dog, cat, or even wild animal. Those eggs hole up somewhere in the environment while larvae develop inside them. This usually takes a couple of weeks. 

  2. Your unsuspecting dog ingests those ready-to-infect worm eggs or the larvae, either by eating contaminated soil, drinking contaminated water, consuming infected feces, or accidentally consuming infected prey. 

  3. The larvae get to where they want to be, attach, grow, and start to reproduce, shedding eggs for the next dog to pick up. 

Now, there may be minor variations in this cycle depending on the type of worm. For example, tapeworms require an intermediate host. This is an animal that serves as a maturation site for the tapeworm larvae. A dog then has to eat that animal in order to get tapeworms. Intermediate hosts can be mice, other small rodents, and even fleas! 

Heartworms are in their own category because they simply don’t follow the same rules as other internal worms. They act similar to tapeworms in that they need an intermediate host: the mosquito. But rather than eating the mosquito, your dog just has to get bitten by an infected bug in order to get heartworm. 

Dogs end up ingesting worm eggs or larvae through eating infected poop, dog or otherwise, eating meat that hasn’t been properly cooked, eating critters that are infected, or sometimes even through contact of the larvae with the skin, such as is the case with whipworms. 

As for puppies, these little guys sometimes don’t even stand a chance as worms from their mother can transmit to them in utero or through their milk while nursing. It just isn’t fair! 

A concerned Beagle sitting by a window, looking outside. The image illustrates a common sign of worms in dogs, such as lethargy or behavioral changes, which may accompany physical symptoms like worms in dog poop.

Humans and Dog Worms 

You read that right, humans can get worms from dogs—kids especially. Humans can pick up internal worms through the same means as dogs. While for us it won’t be about snacking on dog poop or small woodland critters, it can be through touching a contaminated environment and then not washing our hands before eating our lunchtime sandwich. 

Kids are most at risk simply because they tend to not have quite the discretion in what goes into their mouths. As a vet, I have made a habit of mentioning this fact to any families that bring their dog or cat into the clinic. While it may seem like more of a human doctor issue, their family physician may not realize that they have pets and therefore wouldn’t know to warn them about the dangers of dog worms crossing over to humans. 

Signs of Worms in Dogs 

Most healthy adult dogs aren’t going to show you anything if they have a worm or two here and there. When you start seeing signs is when the numbers have become high enough that they cause health issues in your dog, or they start passing in your dog’s poop. 

Worms in dog poop may look long, white and tubular in the case of roundworms, or long and white with a skinnier tail, in the case of whipworms. Hookworms are typically too small to show up and heartworms don’t live in the digestive tract, so you won’t find them in the poop either. Tapeworms may show up as little grains of rice in your dog’s poop or stuck around their anus. Worms in dog poop that is fresh may be moving, while those that are exposed to the elements will die. 

As for what they can do to a dog, again, it takes a heavy burden of intestinal worms to cause a problem in adult dogs, but a not so large number to cause issues with puppies. Heartworms also don’t take record numbers, but they do take more than a few to create signs. Signs of intestinal worms in dogs may include: 

  • Weight loss 

  • Poor hair coat 

  • Bloody stools 

  • Dark stools 

  • Diarrhea 

  • Pale gums 

  • Weakness 

  • Pot belly 

  • Poor growth 

Since heartworms are a different kind of issue, you typically won’t see digestive issues, instead your dog may show: 

  • Coughing 

  • Not wanting to exercise 

  • Becoming tired quickly 

  • Decreased appetite 

  • Weight loss 

  • Pot belly 

  • Collapse 

Diagnosing Worms in Dogs 

Rather than seeing signs, most adult dogs will be diagnosed with worms following a routine fecal test of a dog stool sample. Most vets will run these as part of a dog’s annual wellness or vaccination exam. Of course, fecal tests may be run anytime your dog is showing any digestive signs or those signs listed above. Dogs that are particularly prone may have periodic fecal tests run throughout the year. 

Fecal tests work by sort of separating the worm eggs from the rest of the feces, giving veterinarians a chance to view them under a microscope. These tests work pretty well, though some worms don’t shed eggs 24/7. Rather they shed eggs intermittently, meaning that the sample you bring to the vet may not contain eggs worthy of a diagnosis even though your dog may be carrying worms. Vets may recommend repeated testing if they suspect your dog has some wormy freeloaders. 

Heartworms can be tested for as well, though tests don’t use feces. Instead, heartworm testing requires a small sample of blood, and again, this test may be part of a dog’s annual exam. Heartworm testing should also be done if there is any break in giving their heartworm preventative or when starting a heartworm preventative for the first time. 

Treating Worms in Dogs 

Worms are a part of a veterinarian’s every day, so they’ll be able to prescribe a safe and effective dewormer for your dog. This may consist of a liquid or tablet, both of which are typically easy to administer. It’s important to realize that dewormer can only take care of the adult worms in your dog’s body, they can’t get rid of eggs, larvae or keep them from coming back. This may lead your veterinarian to prescribe a dose of dewormer now and then in a couple of weeks to try to catch those maturing larvae.  

You’ll know the medication is working because dogs will tend to dump all those dead worm bodies out in their feces, making it seem like the problem is multiplying rather than clearing up. Don’t be surprised to see dead worms in your dog’s poop for a week or more. 

Heartworms, again, are a different story. For them the preventative medications only work on microfilaria. Which is great, because you really don’t want to let them mature into adults. Adults are hard to get rid of and require intense treatment which may mean hospitalization. Preventatives come in the form of pills or topicals that you typically give every 30 days in order to kill the developing heartworms before they turn adult and dangerous. 

A dog lying down on dry grass, looking tired and unwell. This image highlights a potential sign of worms in dogs, such as lethargy, which can accompany other symptoms like worms in dog poop.

Prevention of Worms in Dogs 

Since worm eggs and larvae may be literally everywhere in your dog’s environment, they may be hard to prevent. But you can do your best by keeping them on a leash when out and about so that they can’t get into poop, rodents, etc., cleaning up feces in your yard on a routine basis and using a flea preventative. 

Heartworm is best prevented through year-round medications along with annual testing. Some heartworm preventatives will also cover intestinal worms, so ask your veterinarian about different products if you’re looking for a win-win medication. 

On the human front, washing your hands is the best course of action. Always wash before eating and after contact with animal feces. Teach your little ones the importance of handwashing after playing outside, interacting with pets, or using the bathroom. And, of course, discourage them from putting their hands or other objects in their mouths while outdoors. 

Keep on Top of Worms in Your Dogs 

Navigating the world of canine worms can be a worrisome experience, both for pet owners and their furry friends. Unfortunately, treating these pesky parasites can also be expensive. This is where pet insurance can help. 

With dog insurance, you can receive reimbursement for the costs associated with diagnosing and treating worm infestations. This includes medications, office visits, and lab tests.  

While pet insurance can be invaluable for unexpected health issues like worm infestations, it doesn't always cover routine care like annual check-ups, vaccinations, and heartworm preventatives.  

Pet wellness plans are not insurance, but are add-ons to your policy and offer reimbursement for a range of preventive care services. These plans can often include coverage for: 

  • Annual check-ups: Regular physical exams to monitor your dog's overall health and detect any potential problems early. 

  • Vaccinations: Essential vaccines to protect your dog from contagious diseases. 

  • Heartworm preventatives: Monthly medications to prevent heartworm infections, a serious and potentially fatal condition. 

  • Fecal exams: Routine tests to check for intestinal parasites, including worms. 

By enrolling your dog in a pet wellness plan, you can help ensure that your furry friend receives the preventive care they need to stay healthy, all while managing the associated costs. With pet insurance and a wellness plan, you can provide your dog with the best possible care, giving you peace of mind and financial security. 

Say Goodbye to Worms in Dog Poop 

Worms in dogs can be a frustrating and sometimes scary experience, but with a little extra care and attention, you can help your furry friend stay healthy and happy. By understanding the signs of these unwelcome guests, taking preventative measures, and seeking veterinary advice, you can effectively manage and prevent them. So, let's give those slimy critters the boot and ensure our furry friends have a happy, healthy, and worm-free life!