Tapeworms in Dogs: Symptoms, Diagnosis and Treatment

Written and verified by the lawyer Francisco María García

Last update: 22 December, 2022

Tapeworms in dogs or dipylidium caninum was first discovered and investigated in the mid-18th century. Tapeworms are a parasite which live – often undetected – in the intestines of most mammals, including humans.

While they can cause a great deal of discomfort, tapeworms in dogs aren’t life-threatening. However, if you suspect your pet might have worms, it’s important to seek veterinary attention as soon as possible.

One parasite, two hosts

The tapeworm’s journey – from birth to the moment it reaches the host’s intestine – is a long one. The eggs are passed out of a host’s body in feces. Once outside, flea larvae eat the eggs, becoming an intermediary host for the parasites.

Inside the tiny flea larvae, the tapeworm eggs continue to develop, and wait for the moment when they can infect their definitive host. At the same time, the flea larvae grow, and will start to look for a dog or other animal to live on.

The lifecycle of the Dipylidium caninum is complete when the flea is ingested by a mammal. The worm will then attach to the gut wall of its new host, where it will feed.

Once mature, the worms will start to reproduce. Tapeworms are hermaphrodites, meaning they have both male and female reproductive organs, and only one is needed to reproduce.

Tapeworms can measure up to 28″ in length, with a diameter of around 3 mm. 

Symptoms of tapeworms in dogs

The majority of cases of tapeworms in dogs are – for the most part – asymptomatic. However, if you pay close enough attention, there is one thing which can alert you to the presence of a parasite: gravid proglottids.

This is the name given to the egg sacks which are passed out of the body in feces. At first glance, they might look like small grains of rice. The only difference is that they move, stretching and curling periodically. Each capsule contains around 30 embryos.

As well as in their droppings, you may also notice egg sacks in your dog’s bed or anywhere else they sleep, and around the anus.

In serious cases, a dog may also display other symptoms, such as: 

• Dull, patchy fur.
• Weight loss, despite a normal appetite.
• Notable increase in appetite, with no increase in weight.
• Diarrhea or constipation.
• Abdominal swelling. In some cases, the animal may display signs of pain if the stomach is touched.
• Your dog may also drag their behind across the floor in an attempt to alleviate anal pruritus (burning or itching).

Tapeworms in dogs: diagnosis and treatment

The presence of gravid proglottids is enough for a vet to diagnose a case of tapeworms in dogs. 

Your vet will prescribe an antiparasitic, either oral or intravenous, and decide the appropriate length of treatment. In general, this type of treatment will need to be administered over a period of around three weeks.

There’s only one effective, long-term way to eradicate this persistent parasite, and that is to use anti-flea treatment.

Dipylidium caninum can become drug-resistant. Moreover, if the intermediary host (the flea) continues to live on the surface of the animal’s skin, sooner or later the cycle will begin again.

Prevention

The simplest way to prevent tapeworms is to keep fleas at bay. This means thoroughly cleaning any areas of your home these tiny insects might be hiding. There is one other basic thing you can do to prevent dog contracting tapeworms: regular flea treatment.

Tapeworms and humans

Basically, any mammal that comes into contact with fleas is at risk of contracting tapeworms. This includes humans.

Most cases of tapeworms in humans involve young children. They’re the most likely to put dirty hands in their mouths after interacting with pets or playing outside.