As a cat or dog owner, it is important to be aware that your pet may become infected with an intestinal parasite. They can be contracted in many ways: ingesting infected animal feces, contaminated ground area, hunting wild rodents or fleas, and from an infected mother to her offspring during pregnancy or nursing. It is more common for young animals to be infected, although dogs and cats of any age are at risk. The parasites make their home within the digestive system of your pet, robbing your pet of vital nutrients and sometimes irritating intestinal organs. However with proper monitoring and deworming practices, you can avoid these parasites and keep your dog, cat and the rest of your family in good health.
Can I get intestinal parasites from my pet?
Some intestinal parasites are zoonotic, meaning that humans can be infected with the parasite through contact with their dog or cat. Thousands of people (mostly children) are infected with roundworms each year through the ingestion of infective eggs from feces-contaminated surfaces. Elderly people and those on immunosuppressive drugs or with immunosuppressive diseases are also at higher risk. Hence, the Companion Animal Parasite Council and the Centre for Disease Control are advising veterinarians to educate their clients about these risks. For example, roundworms cause a serious condition called “Larval Migrans”, in which the roundworms migrate through the body and may cause blindness if they reach the eyes. Another example of zoonotic infection is “Beaver Fever”, which is the intestinal illness caused by Giardia. The best way to prevent human infection is through the use of good hygiene, including washing your hands and all food sources well, to maintain a clean environment and keep yourself and your pets parasite-free!
How do I know if my cat or dog has an intestinal parasite?
It is unlikely that you will see any adult worms to alert you to an intestinal parasite infection. Furthermore, because many infected dogs or cats do not show any clinical signs, the only accurate way to determine if your pet has a parasite is to look at a sample of its stool under a microscope. In order for the fecal examination to be accurate, it is best to provide a fresh sample of your pet’s stool (passed within 12 hours of the examination). If you do notice any tapeworm segments or adult worms, please save them to show your veterinarian.
Adult dogs and cats should have a fecal examination at least once a year. Puppies and kittens are usually dewormed at their first veterinary visit and should have follow-up fecal examinations performed at subsequent checkups. If your puppy or kitten was dewormed by a breeder or pet store, do not assume that it does not have worms! Some deworming medications only act against one type of worm, and most medications will only kill the adult form of the worm leaving any immature stages to develop inside your pet. Thus, most deworming medications require repeat dosings.
How are intestinal parasites treated?
Different parasites require different medications, however the treatment is relatively easy to administer and affordable. In addition, some heartworm preventive medications also contain deworming ingredients used to treat and control some of the intestinal worms.
If your dog or cat has an intestinal parasite, it is important that you take the proper measures to prevent re-infection. Each dose of the de-worming medication must be given as instructed, and a stool sample should be provided a certain period after the de-worming to ensure that all parasites have been eliminated. The most common source of re-infection is the feces from your pet, which may contain infective eggs if it has been left in the environment for more than a few days. Pick up poop immediately after your pet has relieved itself and wash any contaminated bedding and litter boxes. Some sources also advocate more frequent bathing. Tapeworms are a special concern, since an intermediate host such as fleas or rodents may be present to continue on the infection. If this is the case, you will need to eliminate these creatures from the environment of your pet.
The following are some of the most common parasites encountered in Ontario:
Roundworms
Roundworms are the most common intestinal parasite in dogs and cats. Puppies are primarily infected through the placenta while they are still in the uterus, and kittens are usually infected from their mother’s milk. In addition, roundworms pass thousands of eggs that are shed through the feces of an infected pet. In a few weeks, the eggs develop to an infective larval stage and create the risk of roundworm infection to other cats and dogs that ingest the eggs from a feces-contaminated surface. The worms themselves are rarely seen in feces or vomit, but look like thick strands of white spaghetti that are usually about 3-4 inches long. Most infected cats or dogs do not show any clinical signs, but in heavy infestations your pet may develop a pot-bellied appearance, an unthrifty coat, and may vomit up worms.
Tapeworms
Tapeworms are long worms that have a flat and segmented body. Most adult worms grow to about 50 cm long and live in your pet’s small intestine. They periodically shed small segments of their body that can be found in your pet’s feces or around its anus. If these segments are fresh, they may still be moving about and can irritate your pet’s anus, causing your pet to “scoot” its behind along the ground. If they are old, tapeworm segments look like dried pieces of rice stuck to the fur. The most common species in cats and dogs are transmitted through ingestion of fleas and wild rodents.
Whipworms
Whipworms are occasionally seen in dogs but are very rare in cats. These worms tend to infect adult animals instead of young puppies and kittens. Their name comes from the appearance of the long whip-like portion of their bodies. They live in the large intestine and can cause a foul smelling watery diarrhea that often contains blood. Whipworms are generally not seen in feces.
Hookworms
Hookworms are small, vicious worms that feed on the blood of your dog or cat through the wall of the small intestine. In heavy infections, anemia and a tarry-looking diarrhea can develop quickly – in which case immediate veterinary attention should be sought. Hookworms can be transmitted from mother to her offspring, or from the environment either by ingestion or through contact of skin with the worm.
Protozoa: Coccidia & Giardia
Coccidia and Giardia are extremely tiny single celled organisms cause intestinal infections ranging from mild to severe. If infected, your pet may suffer from heavy diarrhea but often no clinical signs are present. Protozoa infections are common in kennels with high density of animals where the parasites can spread rapidly. Coccidia are often transmitted through fecal-contaminated ground, while contaminated water is a frequent source of transmission for Giardia.
Heartworms
This common parasite got its name because the adult worm lives in the right side of a dog’s heart. Adult worms look much like cooked spaghetti. Heartworm disease is transmitted dog to dog by mosquitoes. Heartworm infection rates are highest in warmer climates and dogs in southern Ontario has the highest canine infection rate in Canada. In this part of the country, infections in cats are rather rare. Dogs with adult heartworm are the source of heartworm for other dogs. Mosquitoes that feed on an infected animal ingest the larvae and transmit them when the mosquitoes bite another animal. In the early stages of the disease, many heartworm-infected dogs show no visible symptoms. But as adult worms mature, dogs may begin experiencing inflammation and narrowing of the lungs’ arteries. This can raise the dog’s blood pressure and eventually cause failure on the right side of the heart. Heartworm disease can be deadly, but it can be treated successfully and even more easily prevented. We recommend that all dogs be on monthly heartworm preventives throughout the summer months.
COMMON EXTERNAL PARASITES OF DOGS AND CATS
Fleas
Adult fleas are small, flat, wingless, and have three pairs of jointed legs. Thay have siphon-like mouthparts and feed on the blood of their hosts by piercing and sucking. Fleas are just about everywhere there are animals. The adult flea spends most of its time on a host, and this is the life-cycle stage pet owners usually encounter, but eggs and larvae can be anywhere – indoors and out. In suitable environments, fleas can breed indoors all year. Fleas on pets can result in obvious irritation and itching but they can also trigger a variety of more serious allergic reactions or skin infections. Fleas can also transmit tapeworms. Because fleas feed on blood, blood loss can result in anemia, with puppies and kittens at particular risk. Scratching may be the first sign that your dog has a problem with fleas. Treating fleas on pets and in the home once there is an infestation can be frustrating, therefore prevention is preferred. We recommend that all dogs and cats having access to the outdoors should be on monthly flea preventives throughout the warmer months.
Ticks
Ticks are a common parasite that feed on dogs. Tick species are found worldwide and may infest dogs in very large numbers, especially during certain times of the year. These blood-sucking parasites are often found in tall grass, where they will attach themselves to a passing animal. Ticks require physical contact to infest your pet, and harpoon-like “teeth” allow them to anchor firmly in place while sucking blood from their animal host. Ticks also act as vectors of disease. Ticks can carry and spread the organisms that can cause Lyme disease, Rocky Mountain spotted fever, several types of ehrlichiosis, and other potentially deadly diseases. A single tick can carry several disease organisms at the same time.
Risk from biting ticks is increased if:
- Tick-borne diseases have been diagnosed in your region
- You and your pet spend time camping, hiking, or hunting in wooded or undeveloped areas.
- You have seen a tick, or previously removed one from your dog.
- Your dog is exposed to wildlife that are frequent tick hosts (deer, rodents, raccoons, etc.).
- Your yard has dense shrubs, tall grass, or leaf litter which serve as common tick habitats.
- You take your dog to wooded areas or grassy meadows.
- Your pet is not on a tick control product.
With the use of combination products, multiple parasites can be prevented with a single monthly dose. As part of your pet’s healthcare team, we would be glad to answer any questions that you have and to provide you with products and information about these products to promote a safe, happy and parasite-free relationship with your pet!
