Tapeworm Infection In Dogs

Tapeworm micrographIt is not uncommon for dogs to get tapeworms.

Any dog can get a tapeworm. The most common tapeworm in dogs Dipylidium caninum is transmitted to dogs by biting or swallowing infected fleas and lice.

However, dogs that are active predators, hunting and eat animals such as rabbits; or dogs that are scavengers and eat bits of carcasses left from coyote kills, dead rabbits etc. can get other species of tapeworm.

Unlike most other common types of canine worm infections such as hookworms or roundworms, the majority of heartworm medications are not preventative for tapeworms. The only heartworm medication that is effective against tapeworms is Iverheart Max.

Find out;

 
What is a tapeworm and what is its structure?

Adult tapeworm of Dipylidium caninumA tape worm is a long flat worm. It is composed of a head and segments about a 1/4 to a 1/3 inch long. The length of a tapeworm depends on the species and how long the dog has been infected. Some can get to several feet in length.

A worm attaches by the head to the intestine. The head has sucking grooves that attach to the intestine. Some species have hooks as well.

The worm grows from behind the head, so the segments closest to the head are immature and those further away from the tail get bigger and mature. The micrograph, at the top of the page, (which is a stained slice) shows the head and some segments.

Each segment develops as it moves further away from the head. When a segment is mature it contains a large number of eggs, shown on the right side of the second image.

Tapeworms do not have a digestive system, they absorb nutrients from the food that is being digested by the dog as it passes by.

How do tapeworms spread and how do dogs get them?

Mature segments at the opposite end from the head, detach and pass out with the feces. The mature segments contain fully developed tapeworm eggs.

Tapeworms need at least one other host to complete the cycle. The type and numbers of intermediate hosts required depends on the species of tapeworm. Intermediate hosts range from fleas and lice (Dipylidium caninum) to fish (Diphyllobothrium latum) to cattle, deer, rabbits etc (Taenia species).

The intermediate species eats the eggs. For instance cattle may eat them if they are on grass, or a flea larva can eat the eggs. The eggs then start to develop and, in most intermediate species, leave the digestive system and enter tissues of the host and mature into a cyst.

When a dog then eats any infected animal (fish, rabbit etc.) or licks an infected flea off its coat, they will probably get a tapeworm infection. In a dog the worms develop and stay in the intestine, only in rare cases do they migrate into tissue.

How do you know if a dog has a tapeworm infection?

The answer is often, at least for a while, you don’t.

If a dog has a severe tapeworm infection you may notice that they are losing weight. However, with a light infection, even though a tapeworm is feeding on digested food and removing some nutrients, there is usually no obvious loss of weight.

Often the appearance of what look like grains of rice in the stool or sometimes seeing segments moving in the fur around the anus of the dog is the first sign that a dog has a tapeworm infection.

How is a tapeworm infection diagnosed?

The presence of tapeworm segments in a stool sample will confirm that a dog has a tape worm infection.

Generally, the species of tapeworm cannot be determined. The structure of the head is the easiest way to determine the infecting species. Usually a dog is treated without species being determined; but occasionally the type of worm may be identified after it has been expelled.

How is a tapeworm infection treated?

Most deworming medications are very effective against tapeworms. The medications paralyze and kill the head, which then releases from the intestinal wall and the worm passes out in the feces.

There are quite a few choices of medications that your vet can prescribe such as Droncit, Drontal Plus and Cestex. Which medication is prescribed depends on the personal preferences of the vet.

Many deworming medications are prescription only, but there are several over the counter dewormers. The best known is Pancur-C, a powder that is sprinkled on food once a day for 3 days. This is what my vet gave me for Hank to eliminate the tapeworm he got last year.

Prevention of tapeworm infection

To reduce the risk of your dog getting a tapeworm infection, it is important to control and eliminate fleas and lice from the anywhere your dog goes. Try to prevent your dog from eating dead animals and do not feed them any raw game meat.

If you live in an area where there is a high level of infection by tapeworms, many vets will recommend routine screening of a stool sample twice a year or routine treatment with deworming product as a preventative. As stated in the introduction the only heartworm medication that is effective against tapeworms is Iverheart Max. (See Heartworm – Table of Common Preventative Medications for a list of medications and which parasitic worms each one is effective against)

In conclusion

The most common source of tapeworms in dogs is from eating infected fleas or lice, with raw meat/dead animals being second. A tapeworm infection in a dog is usually not detected until a while after infection. Treatment is easy and effective in eliminating tapeworms.

Image courtesy of Wikipedia – the narrow end is the head and the other end shows the mature segments detaching

 
See also Worms Of The Digestive System: General Information