Dipilydium caninum

• Dipylidium caninum

  Dog tapeworm

  
• Definitive hosts

  • Humans
  • Dogs
  • Cats
• Intermediate hosts

  • Flea
  • Louse
• Intermediate host

  • Embryo → cysticercoid larva
• Flea species

  • Ctenocephalides canis (dog flea)
  • Ctenocephalides felis (cat flea)
  • Pulex irritans (humans)

  
• Louse species

  • Trichinodectes canis (dog louse)
• Cysticercoid

  Larva with no bladder, unlike cysticercus
• Diagnostic stage

  Gravid proglottid
• Infective stage

  Cysticercoid larva
• Autoinfection: NO
• Dipylidium caninum

  • Intestinal parasite of dogs and cats (especially in dog population)
• Symptoms in humans

  • Intestinal discomfort, epigastric pain, diarrhea
  • Allergic reactions
• Scolex

  • Small and globular with four deeply cupped suckers and a protrusible rostellum, which is armed with one to seven rows of rose thorn-shaped hooklets
• Proglottids

  • Longer than they are wide: Barrel-shaped
  • 2 genital pores versus only one in other cestodes = double pored tapeworm
• Double-pored tapeworm

  Has a pumpkin seed shaped proglottid

  
  

  
  

  
• Ova

  • Packets of 8 – 15 eggs enclosed in a capsule
  • Hexacanth embryo with 3 pairs of hooks
• Cysticercoid

  No bladder (no fluid), unlike cysticercus which has a fluid-filled sac
• Life cycle of Dipylidium caninum

  1. Cats and dogs have fleas in their fur

  2. If the infect flea is ingested by cats/dogs, the encysted larvae (from the flea) becomes an adult (in the definitive host)

  3. Since it is a hermaphrodite, there will be formation of gravid proglottids and a subsequent release of packets of embryonated eggs to the feces and into the external environment

  4. The oncosphere hatches from the egg upon ingestion of intermediate host (larval flea)

  5. In the intermediate host, the oncosphere encysts to become cysticercoid

  6. Humans may accidentally ingest flea with infective cysticercoid, which matures in the small intestine of humans

  7. Mature worms give rise to gravid proglottids and eggs which are excrted with the stool and into the external enviroment and the cycle continues

  
• Pathogenesis and Clinical Manifestations

  • Infection is rarely heavy
  • Minimal symptoms: Slight intestinal discomfort, epigastric pain, diarrhea, allergic reaction
  • Anal pruritus: proglottids are motile when freshly pased
  • Mistaken as maggots
  • Moderate eosinophilia
• Diagnosis

  1. Recovery of characteristic gravid proglottid singly or in chain

  2. Proglottids may crawl out of the anus

  3. Egg capsules is rarely recoverred in the stool

  4. Gravid proglottids do not disintegrate in the intestine (ONLY IN ENVIRONMENT)
• Treatment

  • Praziquantel as single dose
  • Niclosamide
• Prevention and Control

  1. Periodic deworming of cats and dogs

  2. Insecticide dusting of dogs and cats