o
PLATYHELMINTHES
SUBKINGDOM
METAZOA
PHYLUM
NEMATHELMINTH
ES
CLASS
NEMATODA
(roundworms)
SPECIES
PHYLUM
PLATYHELMINTHE
S
CLASS FILARIAE
(tissue
roundworms)
SPECIES
CLASS
TREMATODA
(flukes)
CLASS CESTODA
(tapeworms)
SPECIES
SPECIES
FLAT WORMS
PLATYHELMINTHES
➢
➢
➢
Classes:
•
•
CESTODA
o Order Pseudophyllidea
o Order Cyclophyllidea
TREMATODA
o Blood flukes (Schistosoma)
o Tissue flukes
➢
CLASS CESTODES
➢ Parts:
• Scolex
• Neck
• Strobila: (Proglottids)
➢ Number of segments: varies
➢ Segments are:
• Craspedote
• Acraspedote
• Apolytic
• Anapolytic
➢ Most are Monoecious
➢ Most exhibit Protandry
• Male reproductive organ:
o CIRRUS
o Testes- Hymenolepis (3 testes)
- Taenia (500 or more)
• Female reproductive organ:
o Mature uterus
▪ Coiled
▪ Saccular or lobulated
▪ Tube, straight or branched
➢
➢
➢
Gravid segment
▪ Reticulated with ova
▪ With lateral branches
• Vas deferens and vagina have
COMMON GENITAL PORE that open on:
o Ventral surface
o Lateral margin
▪ Same side
▪ Bilateral
▪ Irregularly alternate
No alimentary tract
No vascular system
Excretory system- PROTONEPHRIDIUM->
FLAME CELL: SOLENOCYTES
• Flame cell- collect excess water and
nitrogen waste
• Excreted through pores in skin
Two main classes of larvae:
1. Solid
a. Procercoid- no scolex; with
oncospiral hooks
b. Plerocercoid- with developing
scolex and strobila
2. Vesicular, bladder or cystic
a. Cysticercoid- slightly developed
bladder
b. Cysticercus/TRUE BLADDER
COENURUS
- Well-developed cyst
- Multiple invaginated scolices
ECHINOCOCCUS or Hydatid Cyst
- Well-developed cyst
- Brood capsules and daughter cells
DIFFERENCE
CRITERIA
Scolex
pseudophyllidea
- spoon, spautal
- almond shape
- 2 sucking
grooves
“bothria”
Genital pore
- center of
proglottid
- center of
segment
- coiled
“rosette”
Uterine pore
Uterus
cyclophyllidea
- 4 muscular
suckers
- with or
without
spines or
hooks
- margins of
proglottid
- absent
- sac-like;
branched
Ova
- operculated
-immature
when laid
Oncosphere
larva
- CORACIDIUM
- ciliated
Metacestode
larva
- solid
- D. latum
- may contain
eggs in
capsule
- nonoperculated
- mature
when laid
- HEXACANTH
EMBRYO
- non-ciliated;
with three
pairs of hooks
- cystic or
bladder
- H. nana
- H. diminuta
- D. caninum
- E. granulosus
- E.
multilocularis
- T. solium
- HT. saginata
DIPHYLLOBOTHRIUM LATUM
➢ Other species
o D. pacificum
o D. cordatum
o D. ursi
o D. dentriticum
o D. lanceolatum
o D. dalliae
o D. yonagoensis
➢ Common name: Fish tapeworm or
Broad tapeworm
➢ Disease: diphyllobothriasis,
bothriocephaliasis, fish tapeworm
infection, broad taperworm infection,
dibothriocephalus anemia; Sparganosis
➢ Found in: Great lakes, Scandinavia,
Western Europe, Japan and South
America
➢ 1st IH (infective host): copepods
(cyclops and diaptomus)
➢ 2nd IH: fresh water fishes
o Pike, salmon, trout, white fish
➢ Reservoir hosts: dogs and cats
➢ Final host: man (25 years old)
NAME OF FISH SPECIES IN SOME EUROPEAN
LANGUAGES *PIC*
➢ Morphology
o Adult: ivory white
▪ Length: 3-10 meters
▪ 4000 proglottids
▪ Scolex
• Almond shaped
• With dorsal and
ventral suctorial
grooves
➢ PROGLOTTID:
o Broader
o Size: 2-4 mm long by 10 to 12
mm wide
➢ OVUM:
o Single shell; operculated
o 30-50 micrometer in size
o Yellowish to yellow-brown
o Immature if found in feces
o 100,000 eggs a day
➢ CORACIDIUM
o Swim freely in the water
➢ PROCEROID
o Measures 550 micro in length
o With 3 pairs of hooklets
➢ PLEROCERCOID/SPARGANUM
o 6 mm in L; glistening, opaque
white
o has an invaginated anterior end
o with developing scolex and
segments
➢ LIFE CYCLE OF D. LATUM
o Undeveloped eggs in feces->
coracidium
o Coracium (1st IH: copepod)->
procercoid
o 1st IH copepod-> 2nd IH
(freshwater fish)
o Procercoid-> plerocercoid in
muscle
o Man consumes infected
freshwater fish
o
SI: plerocercoid attached to
mucosa and matures to adult
worm
*pic
*pic
➢ Diphyllobothriasis, bothriocephaliasis, fish
tapeworm infection
o May be mild
o Abdominal discomfort, loss of
appetite and malnutrition; loss
of weight
o Mechanical obstruction
o Systemic toxemia
o Migration of proglottids can
cause cholecystitis or
cholangitis
➢ Bothriocephalus anemia/ tapeworm
pernicious anemia
o Decreased vitamin B12
o Macrocytic normochromic
anemia
o Thrombocytopenia; mild
leukopenia
➢ SPARGANOSIS:
o MOT: ingestion of infected
cyclops
o Eye, nose, neck, brain and
abdominal viscera
o Intense inflammation and
eosinophilia
➢ LABOTAORY DIAGNOSIS
o Eggs
o Examination of proglottids
o Surgical removal of sparganum
➢ PREVENTION
1. Freezing (-18 degree Celsius)
for 24 hours
2. Thorough cooking or pickling of
fish
3. Fish reservoirs- kept free of raw
sewage
4. Boiling and filtering of drink
water
5. De-worming of reservoir hosts