Hopefully every pet owner knows that they must regularly ‘worm’ their pets. But did you know that “worm” is a very broad category referring to hundreds of different parasites that can live inside your pet’s gastrointestinal tract? Today we will be discussing one specific group – tapeworms. We will talk about tapeworm biology and the different species of dog and cat tapeworms. Also how you can treat and prevent tapeworm infection in your pets.
Tapeworms, as the name suggests, are flat ribbon-shaped worms, which differentiates them from the other common group of worms, roundworms. Adult tapeworms are usually very long (some species can grow over 10m long!), white in colour, and segmented with a head at one end and a segment full of eggs in the other. They have suckers and hooks which they use to attach themselves to an animal’s intestinal wall and feed off nutrients. Unlike many roundworms, tapeworms and their eggs are usually large enough to be seen by the naked eye.
Tapeworm lifecycles are actually more complex than their simple nature might imply. Adult tapeworms are hermaphrodites, meaning they contain both male and female reproductive organs. They can also reproduce sexually or asexually. Eggs grow in a tapeworm’s final segment (the gravid segment) which breaks off and is passed out in their host’s faeces. All dog and cat tapeworms have indirect lifecycles, meaning a secondary intermediate host must consume the eggs before they can infect your pets (more on these hosts later). The intermediate host consumes the eggs, which hatch into larvae and develop. After development, larvae are consumed by the definitive host (our cats and dogs) either from the environment or when the intermediate host itself is eaten. Now inside their definitive host, the tapeworm larvae migrate to the intestines, attach via their suckers and hooks, and develop to adults, ready to complete their lifecycle.
Tapeworms are incredibly common in all species, with signs of infection ranging from none, to mild intestinal upset, to liver damage, to cyst formation in the brain, and even death! Thankfully, there are only a few to worry about in cats and dogs, and they aren’t usually too dangerous to them. But as you will see, there are other reasons we should be preventing tapeworm infection, as you will see below.
Dog and Cat Tapeworms
The “Common” or “Dog Tapeworm”
Our first tapeworm, Dipylidium caninum, affects dogs and cats. It often causes no symptoms, though can lead to increased appetite, irritation of the anus and stomach upsets. Be on the lookout for your pet biting or licking their rear end, or scooting on the floor. The final egg-filled gravid segments can sometimes be seen in your pet’s poop looking like rice grains.
There are two important bits of information to remember regarding this tapeworm: first, Dipylidium’s intermediate hosts are ectoparasites like fleas and lice, which consume the eggs – when your pets grooms themselves and accidentally eat a flea or louse infected by a Dipylidium larva, the lifecycle is complete. This makes flea control crucial in controlling the tapeworm. Secondly, these tapeworms can very very infrequently infect people, particularly children. This is one reason why we recommend not letting pets lick your face, and making sure children do not get too close to pet faeces.
The Taenia family
Secondly we have Taenia – each species in this genus of tapeworm usually has one definitive host, and various intermediate hosts. Humans are hosts for a few species and can become infected by eating meat from an infected intermediate host (this is why pork should be cooked thoroughly). However, the Taenia species that infect dogs and cats do not infect humans. Commonly, dogs and cats are infected after eating animals like mice, rats or rabbits they have hunted, or eating raw pork or beef. Once infected, they can cause liver damage and secondary abdomen infections. Prevention is easier if you stop your pet hunting and do not feed them a raw meat diet.
The nasty ones – Echinococcus
Finally we have Echinococcus granulosus and Echinococcus multiocularis – these tapeworms are unusual because they are very short. E. granulosus only infects dogs via intermediate herbivore hosts like sheep, while E. multiocularis infects dogs and cats via intermediate rodent hosts. Inside our pets, the symptoms are few but the real danger is to people. Humans infected by Echinococcus species results in a nasty disease called hydatid disease, where the larvae burrow into the liver, lungs, eyes or brain and causes cysts. If these cysts burst, they can cause a serious and potentially fatal allergic reaction – there are very few cures.
Thankfully Echinococcus tapeworms are rare in the UK – however, they are more common in continental Europe. With the current global health crisis, summer holidays are likely off the cards. If you do like to travel abroad with your dog, be aware that all dogs entering the UK must be treated with a drug that kills E. multiocularis before being allowed back in, as part of the Pet Passport scheme. The specifics of this are quite complex and likely to change post-Brexit. So when holidaying resumes, please check with your vet what you need to do prior to travel with your dog.
Tapeworm Treatment and Management
So after that barrage of information on these horrible little parasites, you may be wondering what you can do to prevent your dog or cat being infected. As you can see, the danger to our pets is actually very small, However prevention is focused on human health. It is really important you get your pets de-wormed regularly. All tapeworms are susceptible to readily available products that contain the ingredient praziquantel. Praziquantel will kill any tapeworms your pet already has, and prevent any immature ones from developing. It can be given as an injection, tablet or on food – many products will also kill roundworms, so you can kill many birds with one stone! Ask your vet for more information on which product is best for your pet.
You should also make sure your pet avoids the intermediate hosts as much as possible. For the most common tapeworm, Dipylidium caninum, this means you should give regular flea products to kill the little critters. This will, of course, prevent other diseases caused by fleas, so is always recommended. Other avoidance advice for other tapeworms includes preventing your pets hunting small mammals, avoiding raw meat diets, and preventing consumption of farm animal faeces or remains. On the topic of farm animals, the Echinococcus tapeworms can cause hydatid disease in farm species. Therefore Farmers will greatly appreciate you helping to reduce the spread!
Finally, to avoid human infection from pets, please do not let your pet lick your face. If they just licked their rear end, tapeworm eggs (as well as nasty bacteria) can be passed on to you. Keep small children and pregnant women away from any animal’s faeces. Ensure they wash their hands after touching your pet, particularly before touching their mouth or eating food. We will also remind you to cook meat thoroughly before consuming it to avoid infection from farm animal tapeworms (modern farming and meat inspection has made tapeworm infection from meat rare, but it is still a good practice to follow).
So after that crash course in tapeworms, you should be all clued up on how to deal with them. Tapeworms are uncommon, but you can help safeguard human and animal health by following our advice above. If you need any further information on how best to prevent tapeworms in your pets, please speak to your vet.