Dibothriocephalus latus, or diphyllobothrium latum, is a fish tapeworm primarily found in northern hemisphere waters, commonly infesting humans and mammals that consume fish. Symptoms of diphyllobothriasis are often mild and can lead to vitamin B12 deficiency, while diagnosis typically involves identifying proglottids and characteristic eggs in feces. Treatment consists of praziquantel or niclosamide, with individuals at higher risk being those who consume raw or undercooked fish.

1. Dibothriocephalus latus

2. Hashemite University
Diphyllobothrium Latum
Course : Parasitology _ Advanced
Instructor : Dr. Naim Ismail
Presenter : Belal Abu Haneya

4. Outline
• Classification
• Introduction
• Morphology
• Symptoms
• Diagnosis
• Treatment

5. Classification

6. Comparison between Pseudophyllidea and
Cyclophyllidea
Pseudophyllidea Cyclophyllidea
Scolex 2 slit-like sucking 4 cup-shaped suckers
(bothria) with or without hooks
Genital on the flat surface on the margin of the
pore of the segment segment
Intermediate 2 1
host

7. Introduction
• Dibothriocephalus latus, or Diphyllobothrium latum is a fish
tapeworm
• most common in waters of the Northern Hemisphere
• infests humans and other mammals that eat fish, particularly
bears and dogs

8. • measuring 10 meters in length with 4000 proglottids *
• * a segment of a tapeworm containing both male and female reproductive organs

9. • Fertilized eggs pass from the host’s body in the feces
• In a water medium they develop into a hair-like larva
• eaten by tiny crustaceans, which, in turn, are eaten by a fish

10. Morphology
• The adult worm is composed of three segments:
* the scolex (head) * the neck * the lower body
• Each side of the scolex has a slit-like groove, which is
a **bothrium for attachment to the intestine.
• The scolex attaches to the neck, or proliferative region.
• From the neck grow many proglottid segments which contain
the reproductive organs of the worm.
* elongate, dorsal or ventral longitudinal grooves on the scolex of cestoda

15. • D. latum is the longest tapeworm in humans, averaging ten
meters long. Adults can shed up to a million eggs a day.
• In adults, proglottids are wider than they are long (hence the
name broad tapeworm).
• As in all pseudophyllid cestodes, the genital pores open
midventrally.

16. Diphyllobothrium latum at Tadas
Ivanauskas Zoological Museum

17. Life cycle

18. Clinical symptoms
• Symptoms of diphyllobothriasis are generally mild,
and can include
Diarrhea
Abdominal pain
Vomiting
weight loss
Fatigue
Constipation
Discomfort

20. • Approximately four out of five cases are asymptomatic and
may go many years without being detected
• In a small number of cases, this leads to severe vitamin
B12 deficiency due to the parasite absorbing 80% or more of
the host’s B12 intake
• anemia can also lead to subtle demyelinative neurological
symptoms

21. Diagnosis
• Diagnosis is usually made by ..
* identifying proglottid segments
* characteristic eggs in the feces
• these simple diagnostic techniques are able to identify the
nature of the infection to the genus level, which is usually
sufficient in a clinical setting

22. • when the species needs to be determined (in
epidemiological studies)
restriction fragment length polymorphisms ( RFLP )can
be effectively used
* PCR can be performed on samples of purified eggs
* or native fecal samples following sonication of the eggs
to release their contents

23. • Another interesting potential diagnostic tool and treatment is
• the contrast medium, Gastrografin
• introduced into the duodenum
• allows both visualization of the parasite
• shown to cause detachment and passing of the whole worm.

24. Treatment
• The standard treatment for diphyllobothriasis, as well as many
other tapeworm infections is
• single dose of Praziquantel, 5–10 mg/kg PO once for both
adults and children
• An alternative treatment is Niclosamide, 2 g PO once for
adults or 50 mg/kg PO once for children

25. • Praziquantel is not FDA approved for this indication
and
• Niclosamide is not available for human use in the
United States.

26. Epidemiology
• People at high risk for infection have traditionally been those
who regularly consume raw fish.
• Many regional cuisines include raw or undercooked food
including
• sushi and sashimi in Japanese cuisine
• carpaccio di persico in Italian
• tartare maison in French-speaking populations
• ceviche in Latin American cuisine
• marinated herring in Scandinavia.

27. • With emigration and globalization..
• the practice of eating raw fish in these and other
dishes has brought diphyllobothriasis to new parts of
the world and created new endemic foci of disease

28. References
• Muratov, IV; Posokhov, PS (1988). "Causative agent of human
diphyllobothriasis--Diphyllobothrium klebanovskii sp.
n.". Parazitologiia 22 (2): 165–70
• Yamane, Y; Kamo, H; Bylund, G; Wikgren, BJ (1986). "Diphyllobothrium
nihonkaiense sp. nov (Cestoda: Diphyllobothriidae)---revised identification
of Japanese broad tapeworm". Shimane J Med Sci 10: 29–48