Cestodes Flashcards
Flat and ribbon like bodies
It does not have body cavity or alimentary tract
It has excretory, nervous and reproductive system
CESTODES
Forms of Cestodes
Adult, one or more larva, and ova
All have hexacanth (inside the ova) embryo except:
E. granulosus (contains hydatid cyst)
All are heteroxenous, except:
H. nana
All are under Cyclophyllidea, except:
D. latum (under pseudophyllidean)
has hexacanth, sucker/rostellum (apical protrusion) - hooklets for some
Anterior
organ of attachment/adapted
Head (Scolex)
germinal tissues for reproductive organs; region of growth, budding zone
Neck
segments/proglottids
Trunk (Strobila)
no contents just tissues
Immature segment
reproductive organs
Mature proglottid
contains eggs/ova
Ripe/Gravid proglottid
most commonly used to identify tapeworms
- eggs, occasional gravid proglottid and rare scolex after treatment
Stool
For Echinococcus granulosus (can be seen on tissue)
Biopsy
ELISA uses blood/serum agglutination (antigen-antibody reaction)
Serological test
High recovery for cestode’s ova
Perianal swab
Adult Worm in intestines (small)
(Definitive Host)
D. latum
T. solium
T. saginata
H. nana
H. diminuta
Larval Stage in Man
(Accidental Intermediate Host)
D. latum (spaganosis)
T. solium
Echinococcus granulosus
for attachment in the intestinal mucosa
Four cup shaped structure (suckers)
produce hooks, fleshy hooks or apical protrusion
Rostellum
Treatments for tapeworms
removing the scolex in the intestinal mucosa
globular scolex with hooklets
T. solium
retractile globular scolex with Y shape rostellum
H. nana
prominent conical rostellum with protrusion
D. caninum
globular scolex with hooklets
E. granulosus
almond/spatulated/spoon shape
D. latum
globular scolex without hooklets (small rostellum only)
T. saginata
scolex without hooklets rudimentary (undeveloped) apical rostellum
H. diminuta
Region of growth for strobila
Budding zone where segments originates Trunk (Strobila)
Neck
Chain of proglottids or segments
Young/Immature, Mature, Gravid/Ripe
Mature segment
Hermaphroditic segments
gravid segments
Uterus filled eggs
(Gravid Segment) Broader than long
D. latum
(Mature Segment) No distinct
D. latum
(Gravid Segment) Longer than broad
T. solium
T. saginata
(Mature Segment) 100-200 follicular testes
T. solium
(Mature Segment) 300-400 follicular testes
T. saginata
(Gravid Segment) Saccular uterus
H. nana and diminuta
(Mature Segment) 3 testes and 1 ovary
H. nana and diminuta
(Gravid Segment) Coiled/Loosely twisted with midline lateral evagination
E. granulosus
(Mature Segment) 1 set of reproductive structure
E. granulosus
Broad fish Tapeworm
Diphyllobothrium latum
Russian Broad Tapeworm
Diphyllobothrium latum
Only cestode to infect man
Diphyllobothrium latum
a pseudophyllidean
Diphyllobothrium latum
May cause Vitamin B12 Deficiency (Megaloblastic anemia)
Diphyllobothrium latum
Scolex:
With 2 false cuplike suckers or sucking grooves (bothria); almond shape or spatulate or spoon shaped
Diphyllobothrium latum
Proglottid:
Wider than they are ling; Rosette gravid proglottid (central uterine) ovary
Diphyllobothrium latum
Diphyllobothrium latum’s Ova
Shape:
Somewhat oblong
Diphyllobothrium latum’s Ova
Embryo:
Undeveloped, termed coracidium
Diphyllobothrium latum’s Ova
Shell:
Smooth, yellow-brown in color
Diphyllobothrium latum’s Ova
Other features:
Operculum on one end, terminal knob an opposite end
Diphyllobothrium latum’s
Size range:
55-75um long; 40-55um wide
Diphyllobothrium latum’s
Definitive Host:
Man
Diphyllobothrium latum’s
Intermediate Host:
Fresh water crustaceans
Diphyllobothrium latum’s (1st IH)
Copepods/Cyclops
Diphyllobothrium latum’s (2nd IH)
Fresh water fishes (ie. Pile, eel, trout) (2nd IH is usually a smaller fish that is ingested by a larger fish)
Diphyllobothrium latum’s
Infective stage to
o Man:
o 2nd IH:
o 1st IH:
o Man: Plerocercoid (2nd larval stage)
o 2nd IH: Plerocercoid
o 1st IH: Procercoid
not infective
1st larval stage is called procercoid
Armed tapeworm/Pork tapeworm
T. solium
Unarmed tapeworm/Beef tapeworm
T. saginata
T. solium and T. saginata
Definitive Host:
Man
T. solium’s
Intermediate Host:
Pork/Swine
T. saginata’s
Intermediate Host:
Cattles/Cow
T. solium’s
Infective stage:
Cysticercus cellulosae; egg
T. saginata’s
Infective stage:
Cysticercus bovis
T. solium’s Length
2-3m
T. saginata’s Length
5-10m
Scolex:
Small and globular, Rostellum with hooks (Double Crown)
T. solium
Scolex:
Large globular, Without rostellum nor hooks
T. saginata
Proglottid or Segment:
<1000
T. solium
Proglottid or Segment:
1,000-2,000
T. saginata
(natural detachment of gravid proglottid from the main body)
apolysis
Uterus (Lateral branches) Stain:
Square: 7-15 thick and dendritic on each side
T. solium
Uterus (Lateral branches) Stain:
Rectangular; 15-30 thin and dichotomous on each side
T. saginata
have Vaginal Sphincter
T. saginata
Seen on mature segment of T.solium
Accessory ovarian lobe
T. solium and T. saginata’s Ova
Average size:
28-40 um by 18-30 um
T. solium and T. saginata’s Ova
Hooklets:
Three pairs; hexacanth embryo
T. solium and T. saginata’s Ova
Other features:
Radial striations on yellow brown embryophore
Also known as Rat Tapeworm
Hymenolepis diminuta
Scolex:
With four suckers, small (rudimentary) apical rostellum without hooks
Hymenolepis diminuta
Proglottid:
Rectangular; Saclike uterus filled with eggs; often difficult to see
Hymenolepis diminuta
Hymenolepis diminuta’s Ova
Average size:
55 by 85 um
Hymenolepis diminuta’s Ova
Hooklets:
Three pairs; hexacanth embryo
Hymenolepis diminuta’s Ova
Polar thickenings:
Present
Hymenolepis diminuta’s Ova
Polar filaments:
Absent
Hymenolepis nana and diminuta’s Ova
Embyrophore:
Present; colorless
Also known as Dwarf Tapeworm
Hymenolepis nana
Smallest cestode to infect human intestine; deadliest and can migrate to the brain because of its size
Most common cestode in humans
Hymenolepis nana
Scolex:
With four suckers, small rostellum with one row of hooks
Hymenolepis nana
Proglottid:
Rectangular; Saclike uterus filled with eggs
Hymenolepis nana
Hymenolepis nana’s Ova
Average size:
45 by 38 um
Hymenolepis nana’s Ova
Hooklets:
Three pairs; hexacanth embryo
Hymenolepis nana’s Ova
Polar thickenings:
Present
Hymenolepis nana’s Ova
Polar filaments:
Present
Also known as Dog or Cat tapeworm or Pumpkin seed Tapeworm or Double pored Tapeworm
Dipylidium caninum
Infective stage of Dipylidium caninum
Cysticercoid larva
Infective stage to man in H. diminuta
Cysticercoid larva
Scolex:
With four suckers, club shaped armed rostellum with up to seven circlets
Dipylidium caninum
Pumpkin seed mature and gravid proglottid; two sets of reproductive organs (Vase-shape appearance)
Dipylidium caninum
Dipylidium caninum’s Ova
Number of eggs in enclosed packet:
5-30
Dipylidium caninum’s Ova
Diameter range per egg:
30-60um
Dipylidium caninum’s Ova
Individual egg features:
Six hooked oncosphere
Also known as Dog tapeworm or Hydatid Tapeworm
Echinococcus granulosus
Echinococcus granulosus
Definitive Host:
Dogs
Echinococcus granulosus
Intermediate Host:
Sheep and Man (Man is the accidental intermediate host) - Sparganosis
highly antigen that may lead to anaphylactic shock
Hydatid Cyst fluid
skin test for E. granulosus
Casoni Test
Infective stage of man of E. granulosus:
Hydatid cysts
Scolex, small neck, and three proglottids, one at each developmental stage, With twisted or coiled uterus
Adult Echinococcus granulosus
Indistinguishable to Taenia eggs, cannot be recovered in human
Ova Echinococcus granulosus