Diphyllobothrium latum

• Diphyllobothrium latum - is a longest of the tapeworms
• the fish tapeworm can reach a length of about 13 meters
• its eggs consist of ciliated larvae called coracidia.
• one end of the egg is occupied by a lid structure called an operculum.
• human infection of D.latum is through ingestion of improperly cooked or raw fish containing the plerocercoid
• plerocercoid - is the infective stage of D. latum
• Diphyllobothrium latum

  Broad Fish Tapeworm
• Diphyllobothrium latum

  • The longest of the tapeworms, can reach a length of about 13 meters
  • Its eggs consist of ciliated larvae called coracidia (singular coracidium)
  • One end of the egg is occupied by a lid structure called an operculum
  • Its scolex contains a pair of long sucking grooves
  • The gravid segments contain a uterine structure that is centrally located and assumes a rosette formation
• Human infection with D. latum

  1. Ingestion of improperly cooked or raw fish containing the plerocercoid (infective stage)

  2. The plerocercoid attaches to the intestinal mucosa and matures into the adult worm

  3. The adult worm self-fertilizes and the eggs are passed out with the stool

  4. If the eggs come to contact with fresh water, the coracidium hatches and is ingested by the first intermediate host, a tiny crustacean called a copepod (Cyclops sp.)

  5. After ingestion, the coracidium develops into the larval stage called the procercoid

  6. The copepod is then eaten by a freshwater fish (second intermediate host) where the procercoid develops to the plerocercoid
• Definitive hosts for the parasites

  • Humans
  • Dogs
  • Cats
  • Bears
  • Seals
• First intermediate host

  • Crustaceans
• Eggs embryonate

  In water
• Diphyllobothrium latum infection

  Occurs in countries where raw freshwater fish is consumed
• Little damage is produced in the small intestines of the human hosts
• Parasite may compete with the host for vitamin B12


  Leading to a deficiency of this vitamin
• Presentations of Diphyllobothriasis

  • Asymptomatic disease
  • Gastrointestinal involvement (diarrhea, abdominal discomfort)
  • Adult worm attaching to jejunum and ileum
• when the adult worm attaches itself to the jejunum and ileum, the patient may develop deficiency of vitamin B12, leading to anemia similar to pernicious anemia and is characterized as a megaloblastic anemia resulting from the lack of maturation of red blood cells
• diagnosis is based on finding of the characteristic eggs and/or the proglottids (less frequent) in a stool specimen.
• the drug of choice for the treatment of Diphyllobotriasis is praziquantel. an alternative drug is niclosamide.
• Diphyllobothriasis -is the disease of D. latum
• Diphyllobothriasis


  A parasitic infection caused by a tapeworm
• Praziquantel


  The drug of choice for the treatment of diphyllobothriasis
• Niclosamide


  An alternative drug for the treatment of diphyllobothriasis
• Prevention and Control of diphyllobothriasis

  1. Proper sanitary procedures

  2. Thorough cooking of fish prior to consumption

  3. Prompt treatment of infected individuals to prevent spread of the parasite

  4. Freezing of the fish for 24-48 hours at -18 °C to kill all larvae