FINALS: INTESTINAL CESTODES I Flashcards
INTESTINAL CESTODES is under the phylum
Platyhelminthes
the phylum Platyhelminthes is composed of 2 parasitic classes:
- Trematoda (flukes)
- Cestoda (tapeworms)
aka false tapeworm
Pseudophyllidea
aka TRUE tapeworm
Cyclophyllidea
Long, flat and RIBBONLIKE appearance
Important parts include:
o Rostellum
o Scolex
o Proglottids
CESTODES
- May have hook/hooklets
- CROWN of the scolex
- Upper part of the parasite
- Fleshy extension of scolex
ROSTELLUM
- CONTAINS THE SUCKER
o For intestinal mucosa attachment - Suckers are FOUR CUP SHAPE in the scolex part
- Suckers provides the worm the ability TO ATTACH to the intestinal mucosa
SCOLEX
- SEGMENTS of the cestode
- Formed via budding
- Strobila – CHAIN of proglottids Individual segments
PROGLOTTIDS
– self fertilizing
HERMAPHRODITIC
- consist of uterus that is filled with eggs
GRAVID
Cestodes may absorb nutrients and
excrete waste via
TEGUMENT
PSEUDOPHYLLIDEA OR CYCLOPHYLLIDEA?
Scolex: SPOON-SHAPED with bothria (SUCKING GROOVES); hooklets absent
Strobila: (Apolytic) sheds segments
PSEUDOPHYLLIDEA
PSEUDOPHYLLIDEA OR CYCLOPHYLLIDEA?
Scolex: rostellum w/ or w/out hooks
Strobila: (Apolytic) sheds segments
CYCLOPHYLLIDEA
- “Beef tapeworm”
- LONGEST TAPEWORM
- Humans as definitive hosts.
- Activity of segments: ACTIVE CRAWLING
- Adult worm inhabits the UPPER JEJUNUM and can live up to 25 years
- Annually, a worm may pass out 594,000,000 ova.
Taenia saginata
- “Pork tapeworm”
- Humans as definitive (cause intestinal
infection) and intermediate (cause tissue infection) hosts - Activity of segments: not observed
- Number of ova per gravid proglottid:
30,000-50,000 per proglottid - adult worm inhabits the UPPER SMALL INTESTINES
Taenia solium
IDENTIFY:
Scolex: SPHERICAL with four acetabula
(suckers); 1mm
Rostellum: PRESENT, cushion like, doublecrowned (25-30 large and small hooks)
Number of segments: 800-1,000
Acitivity of segments: not observed
Number of ova per gravid proglottid:
30,000-50,000 per proglottid
Length: 2-4 m
Taenia solium
IDENTIFY:
Scolex: CUBOIDAL with four prominent
acetabula (suckers); 1-2mm in diameter
Rostellum: ABSENT; devoid of hooks or a
rostellum.
Number of segments: 1,000-4,000
proglottids
Activity of segments: ACTIVE CRAWLING
Number of ova per gravid proglottid:
97,000-124,000 ova per proglottid
Length: 4-10 m in length
Taenia saginata
- 3RD Taenia spp.
o Reported in Taiwan, Korea, Thailand and Indonesia
o The larvae or cysticercus larvae is found in the LIVER OF INTERMEDIATE HOSTS (pigs, cattle, goats, wild boars and monkeys)
Taenia asiatica
- Spherical/subspherical, measures 30-45
um in diameter - Brownish and striated radially
- Ova has a THICK EMBRYOPHORE
- Inside the eggshell is the oncosphere or
embryo provided with THREE PAIRS OF HOOKLETS (6 hooklets)
Taenia spp. EGG
- Larval stages
- In the tissues of intermediate hosts
- Infective stage both solium and saginata
CYSTICERCOID/CYSTICERCI
CYSTICERCI OF T. saginata
Cysticercus bovis
CYSTICERCI OF T. solium
(“measly pork”)
Cysticercus cellulosae
MOT FOR TAENIA SPP.
VIA INGESTION OF IMPROPERLY COOKED MEAT
IH FOR T. saginata
CATTLE
IH for T. solium?
PIGS
NONSPECIFIC SYMPTOMS OF TAENIASIS?
- EPIGASTRIC PAIN
- DISCOMFORT
- HUNGER PAWS
- WEAKNESS
- WEIGHT LOSS
- LOSS OF APPETITE
- PRURITUS
CYSTICERCOSIS:
o Taenia solium
o Cysticerci often multiple and may
occur in any organ/tissue such as?
- BRAIN
- STRIATED MUSCLE
- SUBCUTANEOUS TISSUE
- EYE
- HEART
- LUNG
- PERITONEUM
Taenia solium
o Most serious manifestation
NEUROCYSTICERCOSIS
NEUROCYSTICERCOSIS 2 GENERAL FORM?
- PARENCHYMAL
- EXTRAPARENCHYMAL
Useful to locate
cysticerci
CAT (Computed Axial
Tomography) and MRI (Magnetic Resonance Imaging) scans
Taeniasis
o The drug of choice is
praziquantel
TREATMENT FOR – T. saginata
Praziquantel
TREATMENT FOR T.
solium
Praziquantel + Niclosamide
TREATMENT FOR CYSTECERCOSIS
o Praziquantel
o Albendazole
PREVENTION AND CONTROL FOR Taenia spp.
- Thorough cooking of meat
- Freezing - 20℃ for 10 - days
- Sanitary inspection of livestocks
- Meat inspections
- “Dwarf tapeworm”
- SMALLEST tapeworm
- Intermediate hosts may not be needed
- The only tapeworm which can complete
their life cycle in one host (in humans)
Hymenolepis nana
“Rat tapeworm”
Accidental parasite for humans
Requires intermediate host
Hymenolepis diminuta
IDENTIFY:
- Scolex: SUBLOBULAR with 4 cup-shaped
suckers
- Rostellum: retractable, 20-30 Y-shaped
hooklets
- Number of segments: SHORTER (175-220)
Length: 25-45mm in length
- Resides in the ILEUM
Hymenolepis nana ADULT WORM
IDENTIFY:
- Scolex: RUDIMENTARY
- Rostellum: ABSENT/ unarmed rostellum
- Number of segments: BROADER
- Length: 60cm in length
Hymenolepis diminuta ADULT WORM
IDENTIFY:
o 30-47 um in diameter
o SPHERICAL/subspherical
o Colorless/clay-colored
o Conspicuous bipolar thickenings W/ 4-8 hair-like polar filaments
Hymenolepis nana OVA
IDENTIFY:
o 60-80 um in diameter
o CIRCULAR
o Bipolar thickenings W/OUT FILAMENTS
o Fan-like hooklets
o Oncosphere is enclosed in inner membrane
Hymenolepis diminuta OVA
DH OF H.nana
HUMANS AND RATS
DH OF H. dimunta
RATS
( HUMANS ARE ACCIDENTAL)
IH OF Hymenolepis nana?
Arthropods
- Rice & flour beetles
(Tenebrio spp.)
IH of Hymenolepis diminuta?
INSECTS
- fleas
- beetles
- cockroach
- mealworms
LIFE CYCLE OF Hymenolepis nana
- Life span of adult worms is ?
4 - 6 WEEKS
LIFE CYCLE OF Hymenolepis diminuta
- Parasite will mature within
20 DAYS
Hymenolepiasis
HEAVY INFECTION CAUSES?
ENTERITIS
(inflammation of the intestine) due to necrosis and can have desquamation
Hymenolepiasis
LIGHT INFECTION:
ASYMPTOMATIC
HYMENOLEPIASIS
H. diminuta are USUALLY LIGHT
Highest number
recorded is
19 WORMS
TREATMENT FOR HYMENOLEPIASIS
PRAZIQUANTEL
(25mg/kg single dose)
