DIPYLIDIUM CANINUM

Dipylidium caninum, also called the cucumber tapeworm or the double-pore tapeworm, is a cyclophyllid cestode that infects organisms afflicted with fleas, including canids, felids, and pet-owners, especially children. Adult worms are about 18 inches long. Eggs (or “egg clusters” or “egg balls”) are passed in the host's feces and ingested by fleas, which are in turn ingested by another mammal after the tapeworm larvae partially develop. Examples of fleas that can spread D. caninum include: Ctenocephalides canis and Ctenocephalides felis.

As in all members of family Dipylidiidae, proglottids of the adult have genital pores on both sides (hence the name double-pore tapeworm). Each side has a set of male and female reproductive organs. The scolex has a rostellum with four rows of hooks, along with the four suckers that all cyclophyllid cestodes have. In cats, sometimes proglottids are visible hanging out of a cat's anus.

Inside fleas, eggs hatch and form oncosphere larvae that move through the wall of the flea intestine into the body cavity where they become cysticercoid larvae, which are infective to mammal hosts.

In children, infection causes diarrhea and restlessness. As with most tapeworm infections, the drugs of choice are niclosamide or praziquantel. The best way to prevent human infection is to treat infected animals and to kill fleas.

Although, D. Caninum is usually transferred via a flea, Trichodectes canis, the chewing louse of dogs, can also be the intermediate host for the tapeworm.

 

FAQs

What is the most common kind of tapeworm dogs and cats get?

The most  common tapeworm of dogs and cats in the United States is called Dipylidium caninum.  Infection is common and found throughout the world.

 

How did my pet get the Dipylidium tapeworm?

By swallowing a flea infected with a tapeworm larvae. A dog or cat may swallow a flea while self-grooming. Once the flea is digested by the dog or cat, the larval  tapeworm is able to develop into an adult tapeworm.

The adult tapeworm is made up of many small segments, called proglottids, each about the size of a grain of rice. Adult tapeworms may measure 4-28 inches in length. As the tapeworm matures inside the intestine, these segments (proglottids) break off and pass into the stool.

 

How would I know if my pet has a tapeworm infection?

Although cats and  dogs are rarely ill as a result of a Dipylidium tapeworm  infection, the proglottids can sometimes be seen crawling near the anus or on  the surface of a fresh bowel movement. Proglottids contain tapeworm eggs; these  eggs are released into the environment when the proglottid dries out. The dried  proglottids are small (about 2 mm), hard and yellowish in color and can  sometimes be seen stuck to the fur around the pet's anus.

 

What kind of problems do tapeworms cause for the dog?

Tapeworms are not  usually harmful to your pet. Weight loss may occur if your pet is heavily  infected. Sometimes, an infected dog will & quot; scoot & quot; or drag its anus  across the ground or carpet because the segments are irritating to the skin in  this area.

Occasionally, a  portion of this tapeworm will be passed when the dog vomits. If this happens, a  worm several inches long may be seen.

 

How is tapeworm infection diagnosed in my pet?

Tapeworm infection  is usually diagnosed when the moving segments are seen crawling around the anus  or in a bowel movement. Dipylidium tapeworm eggs are  rarely released into the feces and are therefore not usually detected by  routine fecal exams performed by your veterinarian. Because of this,  veterinarians depend on you to notify them of possible tapeworm infection in  your pet.

 

Can I get a tapeworm infection from my pet?

Yes; however, the risk of infection with this  tapeworm in humans is very low. For a person to become infected with Dipylidium, he or she must  accidentally swallow an infected flea. Most reported cases involve children.  The most effective way to prevent infections in pets and humans is through flea  control. A child who is infected will usually pass proglottids (or what appears  as rice) in a bowel movement or find them stuck to the skin around the anal  area.

 

How is tapeworm infection treated?

Treatment for both animals and humans is simple and very effective. A prescription drug called praziquantel is given, either orally or by injection (pets only). The medication causes the tapeworm to dissolve within the intestine. Since the worm is usually digested before it passes, it may not be visible in your dog's stool. The drugs are generally well-tolerated.

 

What should I do if I think my child is infected with tapeworms?

See your health care provider for diagnosis and treatment.

 

How can tapeworm infection be prevented?

To reduce the likelihood of infection you should:

  • Control fleas on your pet, and in their indoor and outdoor environments.
  • Have your veterinarian treat your dogs and cats promptly if they have tapeworms.
  • Clean up after your pet, especially in playgrounds and public parks. Bury the feces, or place it in a plastic bag and dispose of it in the trash.
  • Do not allow children to play in areas that are soiled with pet or other animal feces.
  • Teach children to always wash their hands after playing with dogs and cats, and after playing outdoors.

 

BIOLOGY

Causal Agent:

Dipylidium caninum (the double-pored dog tapeworm) mainly infects dogs and cats, but is occasionally found in humans.

 

Life Cycle:

Proposed life cycle of blastocystis hominis

Gravid proglottids are   passed intact in the feces or emerge from the perianal region of the host. Subsequently they release typical egg packets. On rare occasions, proglottids rupture and egg packets are seen in   stool samples. Following ingestion of an egg by the intermediate host (larval   stages of the dog or cat flea Ctenocephalides spp.), an oncosphere is   released into the flea's intestine. The oncosphere penetrates the intestinal   wall, invades the insect's hemocoel (body cavity), and develops into a   cysticercoid larva. The larva develops into an adult, and the adult flea harbours the   infective cysticercoid. The vertebrate host becomes infected by ingesting the adult flea   containing the cysticercoid. The dog is the principal definitive host for Dipylidium   caninum. Other potential hosts include cats, foxes, and humans (mostly   children). Humans acquire infection by ingesting the cysticercoid contaminated   flea. This can be promulgated by close contact between children and their   infected pets. In the small intestine of the vertebrate host the cysticercoid   develops into the adult tapeworm which reaches maturity about 1 month after   infection. The adult tapeworms (measuring up to 60 cm in length and 3   mm in width) reside in the small intestine of the host, where they each attach   by their scolex. They produce proglottids (or segments) which have two genital   pores (hence the name "double-pored" tapeworm). The proglottids mature, become   gravid, detach from the tapeworm, and migrate to the anus or are passed in the   stool.

Life cycle image and information courtesy of DPDx.

For more information view the source:Center for Disease Control

 

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