Many people believe that tapeworms only come from fleas. Other people believe tapeworms in dogs can only be contracted from the feces of other animals that have tapeworms. Both of these methods of transmission are possible.
There are several types of tapeworms that can affect dogs and the method of their transmission varies. The most common tapeworm is Dipylidium caninum. This tapeworm’s life cycle starts as an egg passed in the dog’s feces. The egg is then eaten by a flea or louse and develops into an intermediate stage called a cysticercoid. At this stage the tapeworm is not capable of infecting a dog.
However, once the dog eats the flea containing the cysticercoid it becomes infected. The cysticeroid develops into an adult tapeworm and the cycle starts again.
Another common tapeworm that infects dogs is the Taenia pisiformis. This type of tapeworm has a life cycle that requires an intermediate host, usually small rodents. The rodent must eat the tapeworm to be infected.
There are also some tapeworms a dog can catch by eating the undercooked meat of goats, cattle, and sheep.
A less common tapeworm in dogs is called Echinococcus multilocularis. This tapeworm is normally found only in wild dogs and is transmitted through an intermediate host, again usually a rodent. This infection is of special concern because if a human accidentally ingests an egg from this tapeworm, the intermediate host can develop in the human and cause serious disease. This tapeworm isn’t a common problem in dogs but it is a very serious infection that affects humans.
Tapeworm segments that have dried up usually look like rice grains or sesame seeds. Worm segments that have not dried up will appear to be moving.
If you spot a white thing that looks like rice sticking to the hair around your dog’s rear, you are seeing only one segment of the tapeworm. As the tapeworm wiggles around it spreads more tapeworm eggs. These are then eaten by fleas. When a dog eats the flea it starts the cycle all over again.
The only really effective and safe medications that kill tapeworms in dogs are prescription dewormers that are only available from a veterinarian.