Our pets are victims of several intestinal parasites, some of which are also contagious to you and your family.

During a fecal test — complimentary with a scheduled annual examination in September — we screen for adult parasites and their eggs. Once the parasite has been accurately identified, we prescribe safe and effective treatment options that protect your pet and your family.

The five most common intestinal parasites we are concerned about are roundworms, hookworms, tapeworms, whipworms and coccidia. We address each in turn below.

1. Roundworms

Roundworms are the most common parasitic worms found inside dogs’ small intestinal tracts. Indeed, almost all dogs become infected with them at some time in their lives, usually as puppies.

How are Roundworms Transmitted to Pets?

Your dog may be infected with roundworms from the time it is born because often the mother passes the worms to her puppy while it is still in her body. Roundworms can also develop in a puppy after it’s born when the puppy eats larvated eggs from the environment or drinks worm larvae in the mother’s milk. Another way roundworms are passed is when larvae are present in the tissues of a mouse or another small mammal and the puppy eats the animal.

How are Roundworms Transmitted to People?

Roundworms are the predominant cause of a serious condition called Visceral Larva Migrans. Most victims are small children who are inadvertently infected by consuming worm eggs in soil, typically by putting dirty fingers in their mouths. While the roundworm is not present in its ideal host, it tries to complete its life cycle anyway. The worm gets lost in the human body, classically in the eye, and when it dies generates an extreme inflammatory reaction. If the worm dies within the eye, blindness typically results.

How do Roundworms Affect our Pets?

Aside from being detrimental to humans, roundworms also cause numerous negative effects in our pets. In young animals, it is a common cause of diarrhea and vomiting. The worms themselves can be vomited up which can be alarming as they can be up to seven inches long. The worm consumes the host’s food which leads to unthriftiness and the tell tale pot-bellied appearance. A heavy infection load can also lead to pneumonia and actually block the intestines.

2. Hookworms

Another parasite easily transmitted to humans is the hookworm. With its big teeth, hookworms usually latch on to the wall of the small intestine and suck blood. Unlike other worms that simply absorb the digested food through their skin as it passes by, the hookworm feeds by drinking its host’s blood.  Further, this roaming parasite doesn’t just stay in the small intestine. It tunnels its way to the lungs.

How are Hookworms Transmitted to Pets?

Dogs are infected by hookworms penetrating through their skin, by eating infected soil or by licking it off their paws. It is worth noting that the host getting infected is not always a pet. Other vertebrates such as rodents and birds can pick up hookworm larvae from the soil. If a pet eats an infected rodent or bird, the pet will become infected just the same as if the infection came directly from the soil.

Hookworm is also easily transmissible from an infected mother to her pups. Some members of the litter will be born infected whereas others will become infected by drinking the contaminated milk. Others puppies will become infected from the soil of their own nest which will quickly become contaminated with the stool of their infected littermates. Due to all the blood loss from the feeding parasite, infected puppies are commonly pale and weak with long-standing iron deficiencies. They also may have diarrhea.

How are Hookworms Transmitted to People?

Contaminated soil is an important hookworm source when it comes to a human disease called Cutaneous Larva Migrans. Running barefoot through the park or beach may seem pleasant but if the soil has been contaminated with canine fecal matter, the eager infective larvae may be waiting to penetrate your skin possibly resulting in an hookworm intestinal infection. These infections make for a challenging diagnosis as they are not usually expected and hence over overlooked.

3. Tapeworms

Next is the dreaded tapeworm. Our dogs and cats are often found to have them due to the fact that they are transmitted by eating a flea. So while they are grooming or chewing themselves they inevitably ingest a flea which becomes a tape worm.

How are Tapeworms Transmitted to Pets?

The larval stage of the tape worm is carried inside the adult flea. When the flea is ingested, pets become infected with the tapeworms that attach to the lining of the intestine and rob the body of its nutrients. Your pet may have no outward symptoms but parts of the tapeworm may be seen as small, white, rice-shaped segments around the rectal opening, in feces or on your pet’s bedding.

How are Tapeworms Transmitted to People?

Depending on the variety of tape worm, it can possibly be transmitted to human, becoming encysted in the human liver and causing hydatid disease, a serious liver condition.

4. Whipworms

Along with roundworms, tapeworms and hookworms, whipworm is one of the big five intestinal parasites with which our canine friends must contend. The whipworm of the dog is substantially smaller than the other worms (a mere 30-50 mm in length, about two inches maximum) and is rarely seen as it lives in the cecum, the part of the large intestine where the small and large intestine meet. The adult worms bite the tissue of the intestine, actually embedding their head inside sucking blood.

How are Whipworms Transmitted to Pets?

Eggs are laid inside the large intestine and pass with the stool. Once in the outside world, the eggs require about 2-4 weeks to form embryos and become capable of infecting a new host. Contaminated soil is thus the source of infection, not fresh feces, and soil can remain contaminated for years. It is virtually impossible to remove the eggs from the soil or kill them. Happily, however, this is one pet intestinal parasite that is not readily transmissible to humans.

In dogs, there are four ways by which infection occurs: consuming worm eggs from soil in the environment (generally through normal grooming, licking, chewing); nursing from an infected mother dog; consuming a prey animal (usually rodent) that is carrying developing worms; or, during embryonic development when an infected mother dog is pregnant (with most puppies are infected this way).

When dogs are dewormed with traditional dewormers, this affects only worms in the intestinal tract. It does not affect encysted larvae. It is very difficult to prevent mother to puppy transmission and routine deworming is not adequate. It is possible to prevent infection in unborn puppies by using a specific daily protocol provided by your veterinarian.

How do Whipworms Affect our Pets?

A few whipworms generally do not pose a problem for the host but if large numbers of worms are present and embed in the large intestine tissue, tremendous inflammation can result leading to a bloody, gooey diarrhea. Usually there is not enough blood loss to be dangerous but the diarrhea readily becomes chronic and hard to control.

A second symptom of infection mimics those of Addison’s disease with a waxing and waning weakness accompanied by the inability to conserve salt, ultimately creating a dehydration crisis.

Because female whipworms only periodically lay eggs (whereas other female worms lay eggs continuously), a fecal test may be negative for eggs. This makes the confirmation of a whipworm infection a challenge. It is common to deworm for whipworms if the symptoms are suggestive of their presence even if the fecal test is negative. Most common deworming agents do not work on whipworms so something special must be selected.

5. Coccidia

Coccidia are technically not worms but rather small protozoans (one-celled organisms) that live in the intestinal tracts of dogs and cats. They cause disease most commonly in puppies and kittens that are less than six months of age, in adult animals whose immune system is suppressed or in animals who are stressed in other ways (e.g., change in ownership, another disease present, new pet added to household).

How are Coccidia Transmitted to Pets?

In dogs and cats, there are several different species of coccidia. Regardless of which species is present, the disease is commonly referred to as coccidiosis. Animals shed the cyst in the feces which is how it is passed on to other animals or humans – through fecal contact. There is a 13 day incubation period between exposure to showing signs of infection, which are primarily diarrhea with or without blood. In severely affected animals vomiting, loss of appetite, dehydration and in some instances death may occur if the condition is not addressed.