Q:  What’s the best of dealing with tapeworms in working dogs? I have recently had to treat my dog for tapeworms. How do dogs get tapeworms and how can I prevent them in future?

A: Tapeworms are flat, segmented intestinal parasites. There are several types of tapeworms, but the most common tapeworm species observed in dogs is Dipylidium caninum. This tapeworm uses its hook-like mouthparts to attach to the wall of the small intestine. The adult worms may reach up to 11in (30cm) in length. As the adult matures, individual segments are passed in the faeces of an infected dog. Each segment is about ½in (12mm) long and about ⅛in (3mm) wide and looks like a grain of rice. Occasionally, they can be seen moving on the hairs around the anus or, more commonly, on the surface of freshly passed faeces. These segments contain the eggs of the tapeworm, which are released into the environment when the segment dries and splits open.

Unlike other intestinal parasites, dogs don’t become infected directly by eating these tapeworm eggs. Tapeworms must first pass through an intermediate host before they can infect a dog. The intermediate host for the most common species of tapeworm is the flea. When the tapeworm eggs are released into the environment, they must be ingested by flea larvae, an immature stage of the flea. Once inside the larval flea, the tapeworm egg continues to develop as the flea matures into an adult flea.

A dog could ingest a tapeworm-infected flea during grooming

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. (You might also like to read advice on worming working dogs.)

Preventing tapeworms in working dogs

In most cases, you can prevent tapeworms by controlling fleas on your dog and on other animals in the household, especially cats, as well as in the home environment. Talk to your vet about the most suitable products to use, which might include flea sprays, powder, impregnated collars, oral medication or topical liquid. Also work with your vet to set up and maintain a suitable worming regime. Don’t let your dog roam unsupervised, especially in places where other dogs or animals have been, and always clean up after your dog, especially in your garden and in parks.