Keeping Your Pet Safe From Internal Pests

For many, it’s a sad fact of pet ownership: at one time or another, your dog or cat will most likely come into contact with something that will give your animal an internal parasite. Internal parasites may make pet owners squeamish, but beyond their gross-out factor, many parasites can have serious negative effects on the health of your pet.

The good news is that most parasites are either preventable, or easily diagnosed and treated. The following is a breakdown of the most common parasites that North American household dogs and cats are likely to be infected with, and their treatment and symptoms. For more in-depth information, follow the links below.  

treating cat and dog parasites


Roundworms are the most common internal parasites found in dogs and cats. They can be observed in the feces of infected animals, and can also cause abdominal swelling, butt-scooting behavior, and a variety of other symptoms in pets. They are easily treated with fenbendazole and generally do not cause serious health problems unless left untreated.


Hookworm is an intestinal parasite that can be passed between pets and from pets to humans, so it is especially important to catch it early and treat effectively. Hookworm typically causes diarrhea in affected animals and may also cause a cough if left untreated long enough. Hookworm is difficult to prevent, as it can come from walking barefoot outside.


Tapeworms, though easily treatable, can be hard to detect in dogs and cats as it is mostly asymptomatic. Most infections come from fleas, so keeping your pet medicated against flea infestation is the best way to protect them from getting tapeworms.    


Heartworms are a particularly serious internal parasite. They will cause death of the affected animal if left untreated, and are challenging to treat once a cat or dog is infected. Heartworms were once thought to be only a problem in the Southern United States, but have since spread to all fifty states and Canada. Heartworms infection is more prevalent in dogs, but can also occur in cats. Heartworm is easily preventable with a single or combination of medications.   


Giardia is a protozoan parasite that lives in the intestines of mammals. It is generally contracted by ingesting contaminated water or by consuming the feces of an infected animal. Giardia affects both dogs and cats and is easily treated with a course of antibiotics and bathing. An infected animal’s stool will be soft, greasy, frothy, contain excess mucus, or have a very strong odor.


Ringworm isn’t actually an internal parasite; it’s a highly contagious fungal infection that can be passed from cat to cat and affects their hair, skin, and nails.   

Parasites Are Easily Dealt With if They Are Diagnosed and Treated

Keep a close eye on your pets for any of the signs and symptoms of internal parasites. Make sure to take your pet in for routine examinations on a regular basis, and if they show any of the signs of internal parasites, take them in to see your veterinarian immediately. Effective, inexpensive treatment is available for most parasites if they are caught before they can do real damage.

Author: Giano Panzarella