Unit 3: Helminthes (Cestodes)
56
Lecture 2 – Order Pseudophyllidea
Diphyllobothrium latum
Disease:
Fish tape worm infection, dipyllobothriasis .
Morphology, Biology
The adult worm in the intestine of man is very large,
measures ten meters in length and may have 3OOO_
4Ooo proglottids.
Scolex: (Head): Elliptical or
spatulate 2.5 mm in length by 1
mm in
Breadth, with median ventral and a
median dorsal grooved sucker
(botheria).
Mature segment broader than long
Male genital organ: spherical,
small Testes scattered throughout
the lateral dorsal region, Vas
deferens run forward to the
muscular cirrus which opens into
the genital pore in the middle of
the anterior region.
Female genital organ: Ovary bilobed in posterior region
of proglottids. Vitellaria small follicle scattered through
Out the lateral ventral region , Rosette uterus coiled with
uterine pore Egg : ovoid ,with operculum at one end and a
small thickening of the shell at the opposite end ,.Un
embryonated 58 to 76µm by 4o to 51 µm in width
.
Life cycle
Pathogensis and symptomatology:
D. latum produce no symptom, but infection may cause
digestive disturbance, diarrhea, hunger pain, nausea,
anorexia, vomiting. Sudden vomiting of a portion of
worm may occur. With symptoms suggesting peptic ulcer,
In certain instance carriers develop Pernicious anemia,
called bothriocephalus anemia.
In about 2 percent of the cases megaloblastic anemia
develop .When the worm high up in the jejunum it
absorbs vitamin B 12 from the intestine thus prevents its
combination with intrinsic factor, blocking the absorbtion
of vitamin B12 resulting in its deficiency.
Diagnosis:
Stool examination looking for eggs or segments also
Immunodiagnosis.
Treatment:
Niclosamide
Praziquantel, quinacrine hydrochloride
Epidemiology:
The parasite is prevalent in central Europe. America,
Japan, central Africa where raw fish are routinely
consumed.
Control:
Sanitary disposal of human feces
Thorough cooking of fish, freezing at temp _ 18 degree
centigrate for 48 hours will kill the infective larva.
Avoidance of eating raw or undercooked fish
.