(the other white tapeworm)
Since launching our page on the Common Tapeworm (Dipylidium caninum) we have generated some confusion regarding tapeworms that are not contracted from fleas. There actually is another tapeworm besides Dipylidium whose segments might be seen on a pet’s anal area or on their feces. These other worms are members of the Taenia genus. There are several members of the Taenia genus with which one may come to be aquainted:
- Taenia solium (which infects humans when they consume undercooked pork)
- Taenia saginata (which infects humans when they consume undercooked beef)
- Taenia hydatigena (which infects dogs when they consume undercooked livestock or venison or feed from dead livestock or deer they find out in the world)
- Taenia taeniaformis (which infects cats when they consume rats and mice)
- Taenia ovis (which infects dogs after they consume dead sheep or undercooked lamb)
- Taenia multiceps (which infects dogs that eat the brains of infected sheep)
- Taenia crassiceps (which infects dogs when they consume rats and mice)
- Taenia serialis and Taenia pisiformis (which infects dogs when they consume dead rabbits)
Since we are discussing dogs and cats, we will stick to the Taenia species that infect them.
The life cycle of Taenia tapeworms starts in the host’s intestine, the host being a dog or cat. The worm can be unbelievably long (up to 5 yards for Taenia hydatigena) and is made of segments. Each segment contains an independent set of organs with new segments being created at the neck and older segments dropping off the tail. As segments mature the reproductive tract of the segment becomes more and more prominent until it consists of a bag of tapeworm eggs. These segments, called “proglottids” are passed with the feces into the world where an unsuspecting intermediate host (mouse, rabbit, deer, sheep etc.) swallows one while feeding.
The young tapeworm hatches in the new host’s intestine and escapes into the blood supply with the next stop being the liver. The larval tapeworm wanders through the liver, leaving bloody tracks behind it and ultimately falls into the abdominal cavity where it forms a sac and waits. After about 2 months of development in this location, the larval tapeworm is ready to continue its development but it will need a new host to do so. When the host dies or is killed a predator, the sac and its young tapeworm inside may be consumed accidentally.
About 2 months later, inside the predator, the young tapeworm is now mature and is beginning to shed its first segments and the cycle begins again.
The tapeworm on the right is a member of the Taenia genus while Dipylidium is on the left.
In most cases, tapeworm segments seen are from Dipylidium caninum, which is not called “the common tapeworm” for nothing (i.e. it is very common). The segments of Dipylidium are longer than they are wide and are said to look like grains of rice. The segments of a Taenia tapeworm are wider than they are long.
The good news here is that the same medication, Praziquantel, kills both types of tapeworms efficiently. Where it becomes useful to know one type of worm from another is when it comes to prevention. Dipylidium comes from swallowing a flea; Taenia comes from swallowing carrion or hunting prey.
For more information about Praziquantel click here.
For more information about Dipylidium caninum click here.
Tapeworms do not cause significant symptoms
and are largely of cosmetic concern.
If you see tapeworm segments on your pet’s fur or feces,
see your veterinarian for a tapeworm treatment.
Page last updated: 2/20/2012