Tapeworms belong to the Cestode family of intestinal worms and are one of the most common worms that our dog can get. There are several types of tapeworms, but the most common tapeworm species observed in dogs is Dipylidium caninum. Other tapeworms found in our UK dogs include Taenia species, and Echinococcus granulosus.
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What do tapeworms look like?
Tapeworms are flat, tape-shaped parasites which are made up of individual segments which are connected, just like a chain.
Tapeworms are common internal parasites that affect dogs. The body consists of a head portion (known as the scolex) and the subsequent segments are known as the proglottids. The entire chain can be up to several centimetres long, with the adult worms reaching up to 30 cm in length.
The tapeworm uses its hook-like mouthparts to attach to the wall of the small intestine. As the adult matures, individual segments (the proglottids) are passed in the faeces of an infected dog (the proglottids are about 12 mm long and about 3 mm wide, and look a bit like grains of rice).
Each proglottid is filled with eggs. When ready the whole segment detaches itself from the end of the worm and passes into the faeces or on the coat, looking like small grains of rice.
Occasionally they can be seen moving on the hairs around the anus, or more commonly, on the surface of freshly passed faeces. As the proglottid dries, it becomes a golden colour and eventually breaks open, releasing the fertilised eggs into the environment.
What is the lifecycle of the tapeworm?
Unlike other intestinal parasites, dogs cannot become infected by eating a tapeworm egg; tapeworms must first pass through an intermediate host before they can infect the dog. The most common intermediate host for tapeworms to use is the flea.
When the tapeworm eggs are released into the environment, they must be ingested by the intermediate host – so usually, flea larvae, which is the immature stage of the flea. Once inside the larval flea, the tapeworm egg continues to develop as the flea matures into an adult.
During grooming, or in response to a flea bite, a dog inadvertently ingests the tapeworm infected flea. As the flea is digested in the dog’s intestine, the tapeworm egg is released; it hatches, and then anchors itself to the intestinal lining, therefore completing the life cycle.
Are there other species of tapeworm?
The most common specie is Dipylidium caninum, however other tapeworms can affect dogs. These include:
These are tapeworms that are acquired by eating prey that contains the infective larval stage. These are much larger tapeworms, with the intermediate hosts including rodents, rabbits, hares, and sheep. Infective cysts develop in various organs in the intermediate host. There are effective medications that will eliminate Taenia infections in dogs. If your dog eats prey such as rodents or rabbits, reinfection can occur with the passage of tapeworm segments in 6-8 weeks.
These are very small tapeworms, consisting of only three or four segments, and are usually less than 1 cm in length. Intermediate hosts can be sheep, horses, and occasionally humans. In humans the disease is called hydatidosis, hydatid disease, or hydatid cyst disease, and can result in cysts being formed in the liver.
How are tapeworms transmitted?
Dogs can pick up tapeworms from several sources:
- Some species of tapeworm can migrate into muscle and form cysts. Dogs may become infected by eating undercooked or raw meat from infected animals.
- Fleas can carry Dipylidium caninum larvae. Dogs can swallow infected fleas when grooming, and become infected themselves. This is a common route of infection for dogs in the UK.
- From contact with infected dogs or ground that has become infected with tapeworms via faeces or dead intermediate host animals.
What are the signs of tapeworm in my dog?
There may be no external signs of an early infection with tapeworms. One of the first signs may be the presence of tapeworm segments in faeces or around your dog’s back end – these are often described as ‘looking like moving grains of rice’.
If tapeworms start to physically affect your dog you may see more advanced signs including:
- Itching around the anus (scooting and licking) which in time could cause a skin infection.
- Lack of energy
- Weight loss
- Poor skin and coat condition
If your dog is experiencing any of these signs and you suspect that they might have worms, then you should make an appointment with your vet.
Are tapeworms zoonotic?
As Dipylidium tapeworms are most transmitted by consuming an infected flea in dogs, the risk to human health is quite small.
We are much less likely to accidentally eat a flea! But it is possible….
Believe it or not, humans can be affected by these and other tapeworms, although this is more likely to be from another source, such as undercooked meat or accidentally ingesting soil from the garden or unknown areas such as the park.
Echinococcus granulosus tapeworms are very small (just 2-3mm), and do not cause disease in dogs. They can, however, cause significant disease in humans. An infection can lead to the development of large cysts within the organs – a very dangerous zoonotic problem for humans.
Between 10-20 cases of this are reported in the UK each year, so it is very rare, but human health protection is an important part as to why vets recommend a thorough protocol to protect your dog from tapeworms.
If you think you may have been exposed to a tapeworm, always contact your doctor for advice.
How can I prevent and treat tapeworms in my dog?
You cannot stop your dog being exposed to tapeworms but there are lots of options for preventing infections and for treating them too.
Firstly, regular worming treatments are essential. Worming treatments usually come in the form of tablets or spot-ons and may manage a range of parasites including tapeworms.
The best parasite protocol for your dog will depend on you, your dog, your lifestyle and even the season, and your vet and SQP can help you decide which regime works best for you.
Keeping your dog(s) up to date with flea treatments. This will also help to reduce the risk of fleas infecting your dog with a tapeworm.
Cook any meat thoroughly. This will kill any tapeworms that may be present.
Clean up after your dog quickly. This will help prevent further spread of tapeworms. Hygiene for you and your family is important too, so always wash your hands after playing with your dog.
If there is a risk your dog may have worms, your vet or SQP will prescribe a worming treatment suitable for your dog, which should eliminate the worms. They can also help you plan a worm prevention plan going forwards too; to make sure your dog stays protected. All dog owners should be aware of the signs and symptoms of tapeworm and flea infestation within their dogs, plus how to take steps to prevent its occurrence and treat any problems that arise.
If you have any concerns about tapeworm, other parasitic worms or worming products please seek advice from your qualified RAMA or veterinary surgeon.