How Do I Know If My Dog Has Parasites?

Dogs get into, well, everything. And sometimes sticking their nose, tongue or muzzle in certain unsanitary areas can have repercussions, specifically parasites. That’s right: parasites — tiny organisms that invade your pup’s body and live off their host, often to the detriment of a dog’s health. How do you know if your dog has parasites? Read on to learn what kinds of parasites dogs can contract, and what symptoms they may have if they have a parasitic disease.

What Types Of Parasites Are There & What Are Their Symptoms?

Some of the most common parasites for dogs are worms, wriggly little organisms that grow inside a pup and lodge in their heart or intestines. There are several different types of worms that can infect a dog:


According to Dr. Ernest Ward and Dr. Catherine Barnette of VCA Hospital, heartworm disease is a life-threatening condition that any dog can get from a mosquito bite, where an adult mosquito injects its larvae into the pup’s bloodstream. Common signs your dog may have heartworm include fatigue, coughing, and general unwellness. If left untreated, heartworm can damage a dog’s heart and lungs, and is considered to be “one of the most serious conditions seen in small animal practice.”


Roundworm is the most common parasite found in dogs, and affects puppies more than adult dogs. Puppies can be infected from birth if their mother has roundworm, or they can contract the disease immediately after birth from nursing. Even if their mother isn’t infected, puppies are still prone because they’re more likely to eat the roundworm eggs found in the feces of an infected animal. If a pup has roundworms, their growth may be stunted and they may have other symptoms like coughing, vomiting, diarrhea, and a “pot-belly.” In severe cases, you might be able to see the roundworms — long spaghetti-like creatures — in their feces or vomit.

Canva - Vet With Dog


Dogs contract hookworm by eating the feces of an infected animal or by simply playing (and then licking) infected dirt. These parasites attach to the intestines and then siphon off a dog’s blood. The level of blood loss can be particularly harmful to puppies and can also result in malnourishment, stunted growth and anemia. Dark, sticky diarrhea can also be a symptom of hookworms.


Tapeworms are large, segmented worms found in the intestines of dogs. While extremely gross, the good news is they cause relatively little harm to your pup. Dogs contract tapeworms by eating contaminated animals, such as adult fleas or small mammals. Symptoms can include mild diarrhea and a change in appetite. Often times, there can be no symptoms at all, though you may see some segments of the worm by your dog’s anus or in their feces. If you’re lucky, like this writer once was, you might get a full tapeworm coming out of your pet’s anus — which you at first unthinkingly pull off because it looks like a spaghetti noodle, not an intestine - latching parasite.


Whipworms are shorter worms, often only 1/4 of an inch long, and end up in a dog’s large intestine when the pup (once again) sniffs around in or eats infected dirt or feces. Symptoms here again are chronic diarrhea and weight loss.

Non-Worm Parasites

Tired of worms! Don’t worry — there are non-worm parasites as well, since parasites are nothing if not plentiful. Two of the most common ones for dogs are the single-celled parasites Coccidia and Giardia.

Coccidia is most often found in puppies. These parasites lodge into the intestine after a pup swallows infected soil or dog feces. Diarrhea is the most common symptom of this disease, and in some cases can be fatal if not treated.

Giardia affects older dogs more often than puppies. Dogs contract the disease by drinking infected water (AKA water that has been in contact with contaminated feces). Symptoms can be non-existent or include the usual parasite signs, such as diarrhea, vomiting, and weight loss.

Canva - Dog during taking medicine

How Can I Prevent Or Treat Infection?

If your dog has any of the symptoms mentioned above, the immediate step is to make an appointment with your veterinarian so they can properly diagnose your pup. Once the particular parasite is identified, your doctor can then guide you through the correct course of treatment.

If you want to reduce the risk that your dog ever gets infected, the good news is there are some preventative measures you can take. Heartworm in particular can be easily prevented by giving your pup a monthly pill, something that is high recommended given the severity of the disease. Common heartworm medications are Heartgard and Trifexis — talk to your vet to determine what kind is the best for your pup.

As you can guess from the way most dogs contract parasites, the way to prevent infection is to make sure the area your pup plays in is free of dog feces (or any other type of feces, for that matter) and regularly cleaned. Who really wants fecal matter near them anyway? If you clean it up regularly, you, your pup, and your neighbors will thank you.

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