What are tapeworms?
The adult Dipylidium caninum lives in the small intestine of dogs or cats. It is hooked onto the intestinal wall, and once docked to the host’s intestinal wall the tapeworm begins to grow a long tail. Each segment making up the tail is like a separate independent body – each segment has its own digestive and reproductive system. The tapeworm absorbs nutrients through its skin as the food digested by the host flows past it. As the segment matures, it drops off the larger body and is basically just a sac of tapeworm eggs.
The sac is passed from the host’s rectum and out into the world, either on the host’s stool or on the host’s rear end. The segment is the size of a rice grain or cucumber seed and is able to move. Eventually the segment will dry up and look more like a sesame seed. The sac breaks and tapeworm eggs are released. These eggs are not infectious to mammals.
How did my pet get them?
The common tapeworm comes from fleas, fleas, and only fleas! Larval fleas are generally hatching in the vicinity of the tapeworm sacs, and these larvae fleas are busy grazing on organic debris and flea dirt. The flea larvae do not pay close attention to what they eat and innocently consume tapeworm eggs.
As the larval flea progresses in its development, the tapeworm inside it is also progressing in development. By the time the flea is an adult, the tapeworm is ready to infect a dog or cat. The young tapeworm is only infectious to its mammal host at this stage of development. The flea goes about its usual business, namely sucking its host’s blood, when to its horror it is licked away by the host and swallowed!
Inside the host’s stomach, the flea’s body is digested and the young tapeworm is released. It finds a nice spot to attach and the life cycle begins again. It takes 3 weeks from the time the flea is swallowed to the time tapeworm segments appear on the pet’s rear end or stool.
There are other tapeworm species (Taenia sp.) that are much MUCH less common. These come from eating carrion or prey only – and typically only from rats, mice, or poor little bunnies.
Are there symptoms I should look for?
The primary symptom is seeing the tapeworm segments in the stool, on the tail feathers, or on the bedding. Generally, tapeworms are not considered harmful to the pet in and of themselves – the amount of nutrients they absorb is minimal and there is more than enough flowing by them. Diarrhea, vomiting, and other systemic signs are not associated with common tapeworm infection.
Since the common tapeworm comes from fleas, fleas, and only fleas – seeing tapeworm segments is a symptom of fleas/flea larvae/eggs in the environment.
Who can get them?
Dogs and cats, any age. People can get the Dipylidium tapeworm, too – but only via the same route, i.e. ingesting an infected flea.
How do I tell if my pet has them, and how do we get rid of them?
Visual exam of tapeworm segments is diagnostic. We rarely see tapeworm eggs in a fecal exam because the egg packet needs to break open for the egg to be seen in a fecal flotation. However, it may be still helpful to evaluate a stool sample for other parasites.
The common tapeworm is flat and longer than wide, while the Taenia sp. are flat and wider than long. Fortunately, a single dose of praziquantal-containing dewormer will effectively clear both species of tapeworms. The dewormer essentially “dissolves” the tapeworm body so we do not see “more” tapeworm segments after a deworming. Praziquantal has a high efficacy rate – so if tapeworms are seen again, it is not because the dewormer did not work – it’s because there are still flea larvae in the environment.
What’s the prognosis?
Excellent, as long as appropriate FLEA CONTROL is instituted. Did I mention that tapeworms come from fleas?