Tapeworm Infection in Dogs
What are tapeworms?
Tapeworms are flattened intestinal worms that are made up of many small segments, each about ¼ – ½ inch (3-5 mm) long. Unlike roundworms that live freely in the intestinal tract, tapeworms attach to the wall of the small intestine by hook-like mouthparts.
The most common tapeworm of dogs and cats is Dipylidium caninum. The adult worms may reach up to 8 inches (20 cm) in length. The individual segments are developed from the head end and gradually mature, finally being shed at the opposite end, either singly or in short chains. These segments are passed in the feces when the dog defecates. They are about 1/8” (3 mm) long and look like grains of rice or cucumber seeds. Occasionally they can be seen moving on the hairs around the anus or on freshly passed feces. As the tapeworm segment dries, it becomes a golden color and the fertilized eggs are released into the environment.
Unlike roundworms, dogs cannot become infected by eating fertilized tapeworm eggs. Tapeworms must first pass through an intermediate host, a flea, before they can infect a dog or cat.
How do dogs get tapeworms?
When the infected eggs are released into the environment, they have to be swallowed by immature flea larvae in the environment. Once inside the larval stage of the flea, the tapeworm egg continues to develops into an infective tapeworm as the flea matures into an adult flea. During grooming or in response to a flea’s bite, the dog can ingest the flea carrying the infective tapeworm and the life cycle is completed.
Are tapeworms dangerous for my dog?
Tapeworms do not normally cause serious health problems in dogs. Occasionally dogs will drag their bottoms on the ground scooting in order to allay this irritation but this behavior can be for other reasons such as impacted anal sacs.
In puppies, heavy tapeworm infestation can be more serious. Lack of growth, anemia and intestinal blockage can occur. Occasionally, the head of the tapeworm or scolex detaches from the intestinal wall. The worm can then be passed either in the feces or vomited.
How is diagnosis made?
Clinical diagnosis is usually made by observing the white mobile tapeworm segments in the feces or crawling around the anus. They often look like grains of rice.
Tapeworm segments are only passed intermittently and therefore are often not diagnosed on routine fecal examination. If you find any segments, white or golden color, bring these to us for a definitive diagnosis.
What is the treatment?
With today’s drugs, treatment is safe, simple and effective. The parasiticide may be given either in the form of tablets or by injection. It causes the parasite to dissolve in the intestines so you normally will not see tapeworms passed in the stool.
These drugs are very safe and should not cause vomiting or diarrhea or other adverse side effects.
Is there anything else I should do?
Flea control is critical in the management and prevention of tapeworm infection. Flea control involves treatment of your dog and the environment. Your veterinarian can recommend safe and effective flea control for your pet. If your dog lives in a flea-infested environment, re-infection with tapeworms may occur in as little as two weeks. Since tapeworm medication is so effective, recurrent tapeworm infections are almost always due to re-infection from fleas and not failure of the product.
Can I get tapeworms from my dog?
Contracting tapeworms from your dog is not common or likely. Dipylidium caninum, the most common tapeworm of the dog, depends on the flea as the intermediate host. A person must swallow an infected flea to become infected. A few cases of tapeworm infection have been reported in children. Vigorous flea control will also eliminate any risk of children in the environment becoming infected.
Although Dipylidium species are the most common tapeworms in dogs, other Cestodes are also important in certain areas.
Taenia species – These are tapeworms are acquired by eating prey or waste containing the infective larval stage. These are much larger tapeworms, often up to one yard (one meter) in length. Intermediate hosts include rodents, rabbits, hares and sheep. The intermediate stages develop hyadatid cysts in various organs. We have excellent treatment for Taenia infections in dogs.
Echinococcus species – By contrast, these are very small tapeworms. They consist of only three or four segments and are usually less than 3/8” (1 cm) in length. Intermediate hosts can be sheep, horses and occasionally man. Infection is by ingesting eggs that have originated from the feces of dogs or foxes harboring the adult tapeworm. Fortunately de-worming preparations, particularly those containing praziquantel are effective for eliminating the Cestode from the dog.
Control measures to prevent tapeworm infection from Cestodes involve avoidance of uncooked or partially cooked meat or waste.
Tapeworm Infection in Cats
Tapeworms are intestinal parasites of the cat and dog. Because they are classified as cestodes, they belong to a different family than the hookworms and roundworms which are called nematodes. Several types of tapeworms are known to infect cats. Dipylidium caninum is by far the most common one.
The tapeworm uses its hook-like mouthparts for anchoring to the wall of the small intestine. Eventually, adult tapeworms may reach several inches in length. As the adult matures, individual segments called proglottids break off from the main body of the tapeworm and pass into the cat’s feces.
Are certain cats more likely to get tapeworms?
Fleas are the intermediate host for the Dipylidium caninum. In other words, the tapeworm is unable to complete its life cycle without the presence of fleas in the environment. Regardless of whether the owner may have seen fleas, the cat must have ingested a flea in order to have tapeworms. Consequently, tapeworms are more common in environments that are heavily infested with fleas. Lice are also reported as intermediate hosts for tapeworms but they are relatively uncommon parasites of cats.
How do cats get tapeworms?
First, tapeworm eggs must be ingested by flea larvae, an immature stage of the flea. Contact between flea larvae and tapeworm eggs is facilitated by contaminated bedding or carpet. Adult fleas do not participate in this part of the tapeworm lifecycle. The infected flea larvae will mature into adult fleas.
Next, the cat chews or licks its skin as an adult flea bites and swallows the flea. As the flea is digested within the cat’s intestine, the tapeworm hatches and anchors itself to the intestinal lining.
What are the clinical signs of tapeworm infection?
Tapeworms are not particularly harmful to the cat and few clinical signs are attributed to their presence. Usually, the cat is presented because of the owner’s aversion to the presence of the crawling proglottids. Rarely, tapeworms may cause debilitation or weight loss if they are present in large numbers. Acat will occasionally scoot or drag its anus across the ground or carpet due to the anal irritation caused by the proglottids. However, this behavior is much more common in dogs than cats.
Occasionally, a tapeworm will release its attachment in the intestines and migrate to the stomach. When this happens, the cat may vomit an adult tapeworm several inches in length.
How are tapeworms diagnosed?
Most commonly, owners recognize that the cat has tapeworms and bring this to the attention of the veterinarian. When terminal segments of the tapeworm break off and pass into the cat’s stool, they can be seen crawling on the surface of the feces. These proglottid segments look like grains of cooked white rice or cucumber seeds. Less commonly, they are seen crawling around the cat’s anus. Each of these proglottid capsules contains up to twenty tapeworm eggs.
When these proglottids are released into the environment, they dehydrate and harden. becoming smaller and taking on a golden hue. Eventually, they break open and release their contents . Be aware that tapeworms are not readily diagnosed with routine fecal examinations. Because of this, you should notify your veterinarian when tapeworm segments are found in your cat’s stool.
What is the treatment for tapeworms?
Tapeworm treatments are safe and effective. The deworming medication called an anthelmintic may be given as a tablet or an injection. After treatment, the tapeworm dies and is usually digested within the intestine, so worm segments don’t usually pass into the stool. Side-effects, such as vomiting and diarrhea, are rarely reported with the newer tapeworm medications.
Flea control is the cornerstone of preventing tapeworm infection. With the new and exciting flea control products that have become available, this is now much easier than ever before. Depending on the type of product you use and the presence of other pets in your home, youmay also need to treat your house and yard for fleas. With some of the newer products, environmental control of fleas may not be needed. Circumstances vary, however, so be sure to talk to your veterinarian.
If the cat lives in a flea-infested environment, tapeworm infection can become re-established within a few weeks. This is very rarely due to treatment failure; in most cases, reappearance of tapeworms represents reinfection of the cat. Additional recommendations include:
1. Prompt treatment when tapeworms are detected.
2. Appropriate disposal of all pet feces, especially in public parks, yard, or playgrounds.
3. Strict hygiene practices for children after playing outdoors.
What is the prognosis?
New medications are safe and effective. The prognosis for successful treatment is excellent. Prevention is a successfully accomplished by using a monthly flea preventive
Are cat tapeworms a danger to me or my family?
Humans can become infected with tapeworms, although infection is rare because it is requires ingestion of a flea. Most reported cases have involved children. The risk for human infection with Dipylidium caninum is quite small but does exist.
What are the other tapeworms that can infect my cat?
The other common tapeworms that can infect a cat are members of a group called Taenia. The intermediate host of these tapeworms is mice, birds, or rabbits. In a similar manner to Dipylidium transmission, cats acquire Taenia infestations by eating infected mice, birds, or rabbits.
Another less common group of tapeworms called Echinococcus is of increasing concern as a threat to human health. These tapeworms cause serious, potentially fatal, disease when humans become infected. Infection with this parasite is harder to diagnose than Dipylidium because the segments are small and not readily seen. Trappers and hunters in the north central United States and south central Canada may be at increased risk for infection with this worm when strict hygiene is not practiced. Foxes and coyotes and the wild rodents upon which they prey are important in the life cycle of this parasite. Dogs and cats may also become infected if they eat rodents carrying the parasite. When eggs of Echinococcus are passed in the feces of the dog and cat, humans are at risk for infection. Free-roaming cats and dogs may need to be periodically treated with tapeworm medication. Rodent control and good hygiene are important in preventing the spread of this disease to humans. As with the more common tapeworm, infection with Echinococcus is infrequent yet possible.
My child has pinworms. Did they come from my cat?
Tapeworms and pinworms look very similar. However, contrary to popular belief, pinworms do not infect cats or dogs. Any worm segments seen associated with cats are due to tapeworms. Children who get pinworms do not get them from cats or dogs.
This client information sheet is based on material written by Ernest Ward, DVM.
© Copyright 2005 Lifelearn Inc. Used with permission under license. January 13, 2017