Trematodes Flashcards
T OR F
Trematodes are roundworms
FALSE
Trematodes are flatworms
2 classes of flatworms
Flukes (Class Trematoda)
leaf-like
Tapeworms (Class Cestoda)
ribbon-like
leaf-life:
ribbon-like
leaf-life : Flukes (Class Trematoda)
ribbon-like: Tapeworms (Class Cestoda)
What is the first intermediate host for all the trematodes?
Snail
each of the snail are only specific for a particular parasite
Fascioplopsis buski infects what organ in humans?
Small intestine
The determination of Fasciolopsis versus Fasciola can only be accomplished in the laboratory by the recovery of what parasitic stage?
Adult worm
eggs are difficult to differentiate
What procedure must be done to recover the adult form of Clonorchis sinensis?
Surgery / Autopsy since Clonorchis is a liver fluke
Biopsy can also be done
What is the specimen of choice for the recovery of Heterophyes and Metagonimus?
Stool
What is the typical transmission route of Paragonimus to humans?
Ingestion of contaminated/infected second intermediate host (crayfish or crab)
Paragonimus is a lung fluke but the transmission is via ingestion and not inhalation
trematodes are classified based on
habitat of the adult
T OR F
All trematodes are flat and leaf-like
FALSE
All except Schistosomes.
Schistosomes are cylindrical in nature
term that refers to the parasite containing both the female and male reproductive organs in one adult
hermaphrodite or monoecious
T OR F
All are hermaphrodites except Schistosomes.
TRUE
Schistosomes have male and female adult
T OR F
All have well developed reproductive organs except for Schistosomes
FALSE
All have well developed reproductive organs
Term that refers to the egg cap, lid-like structure that acts as a passageway for the first larvae
Operculum
T OR F
All eggs are operculated
FALSE
All eggs are operculated except Schistosomes.
Schistosomes are non-operculated
T OR F
All require 2 IH except Schistosomes
TRUE
Schistosomes only require one intermediate host (snail) for its complete life cycle
T OR F
All have MOT of Oral/ingestion except for Schistosomes
TRUE
Schistosome - skin penetration of cercaria (infective stage)
Infective stage of Trematodes
Metacercaria
EXCEPT for Schistosome IS is Cercaria
What are the species that have larval stages which can penetrate the skin
- Schistosome (Cercaria)
- Hookworm (L3 Filariform)
- Threadworm (L3 Filariform)
T OR F
All trematodes have complete alimentary canal
FALSE
Alimentary Canal / Digestive tract is incomplete
T OR F
All possess 2 suckers except for Schistosomes
All possess 2 suckers except H. heterophyes
H.heterophyes has a third sucker called genital sucker or gonotyl
What are the suckers of trematodes/flukes and their uses
Oral sucker - mouth
Ventral sucker / Acetabulum - attachment
Genital sucker (H. heterophyes ONLY)
What does the cercaria look like
Cercaria is the IS of Schistosomes
It has forked tail (notched tail)
Big eggs
Schistosomes, Paragonimus, Fasciola, Fasciolopsis
Small eggs
Clonorchis, Opisthorchis, Heterophyes, Metagonimus
One way to identify trematodes are based on the
larvae inside
Embryonated /Mature Eggs
Schistosomes, Clonorchis, Opisthorchis, Heterophyes, Metagonimus, D. Dendriticum
Unembryonated/Immature Eggs
Paragonimus, Fasciola, Fasciolopsis, Echinostoma
Sample of choice to isolate the diagnostic stage
Stool
EXCEPT Schistosoma haematobium because it is found in urine
What is the diagnostic stage of trematodes
eggs
5 Larval stages
Miracidium
(1st IH) Sporocyst, Redia, Cercaria
(2nd IH) Metacercaria
Adult
Schistosome larval stages
Miracidium
(1st IH) Sporocyst, Cercaria
Adult
Fasciola hepatica is also called the
Liver fluke / Temperate liver fluke / Sheep liver fluke
Unique characteristic of adult Fasciola hepatica is
Prominent Cephalic cone and Shoulder
Large, broad and flat body
Unique characteristic of Fasciola hepatica egg
Hens egg
Unembryonated (immature)
Operculated
Fasciola gigantica is also known as the
Tropical liver fluke
Differences of Fasciola hepatica and Fasciola gigantica
Fasciola hepatica = prominent cephalic cone and developed shoulders
Fasciola gigantica = shorter cephalic cone and less developed shoulders
Isolating
eggs:
adult:
eggs: stool
adult: surgery (biopsy or autopsy)
What is pseudofascioliasis
you have ingested a contaminated liver fluke and presence of eggs in the stool but you are not infected
Clonorchis sinensis is also known as
Chinese liver fluke
T OR F
We can differentiate the eggs of Clonorchis and Opisthorchis
FALSE
eggs ng Clonorchis and Opistorchis, we cannot differentiate them
T OR F
eggs of clonorchis are embryonated
TRUE
Unique characteristic of Clonorchis egg
there is still shoulder near the operculum
SMALL KNOB opposite of the operculum
T OR F
adult clonorchis and opisthorchis are almost similar
TRUE
Difference between adult clonorchis and opisthorchis
TESTES
Clonorchis = highly brainching
Opisthorchis = lobed
Two types of Opisthorchis
Viverrini
Felineus
(Opisthorchis) Difference of
Viverrini
Felineus
Viverrini = deeply lobed testes
Felineus = shallow lobed testes
found in the middle third of the body at the level of the uterus
Vitellaria
What eggs are stained with potassium permanganate
Opisthorcis eggs
Associated with renal stone / calculi
Opisthorcis
T OR F
Eggs of Chlonorchis are indistinguishable from each other, but adults are distinguishable
TRUE
DICROCOELIUM DENDRITICUM is also known as
Fasciola dendriticum or Fasciola lanceolata
Lanceolata fluke or Lancet fluke
Resembles a lancet
D. dendriticum or Fasciola dendriticum
Distinguishing feature of adul D. dendriticum / Fasciola dendriticum
testes is below the acetabulum
NO shoulder
Pancreatic flukes
Euretyma pancreaticum – ZOONOTIC INFECTION
The eggs of Euretyma pancreaticum resembles the
lancet flukes
Intestinal flukes
Fasciolopsis buski
Echinostoma Ilocanum
Heterophyes heterophyes
Paragonimus Westermani
Fasciolopsis buski is also known as
Giant intestinal fluke
Habitat of Fasciolopsis buski
Intestine
Eggs of fasciolopsis is similar to
eggs of the fasciola
Difference between adult fasciolopsis and fasciola
Fasciolopsis doesn’t have cephalic cone and shoulders
Fasciolopsis is mataba kasi walang leeg
Echinostoma ilocanum is also known as
Garrison’s fluke
Unique feature of the adult Echinostoma ilocanum
Collar of spines / Circumoral disk
Heterophyes heterophyes is also known as
Von Siebold’s fluke
Distinguishing feature of adult H. heterophyes
Pyriform shaped
Smallest but deadliest
presence of gonodyl / genital sucker
Distinguishing feature of H. heterophyes egg
light brown
ovoid shape
operculated
similar to Clonorchis and opisthorchis BUT Clonorchis and opisthorchis egg has knob-like protrusion
Paragonimus westermani also known as the
Lung fluke / Oriental lung fluke
Distinguishing feature of adult paragonimus westermani
Reddish-brown
Coffee bean shaped
Rounded anteriorly but tapered posteriorly
Distinguishing feature of paragonimus westermani egg
Oval, yellowish-brown, thick shelled
Flattened but prominent operculum
Abopercular portion (thickening at the opposite of the operculum)
Paragonimus westermani egg can be mistaken as
broad fish tapeworm
Paragonimus westermani infection will develop
TB-like infection / primary tuberculosis
Schistosome is also known as
blood fluke
Habitat of schistosome
blood
What are the schistosomes
Schistosoma japonicum
Schistosoma mansoni
Schistosoma haematobium
How to differentiate the schistosomes
Best way to differentiate (up to the species level) is the appearance of the egg.
Features of schistosomes that are different from the rest of the trematodes
cylindrical in nature
dioecious
non-operculated
Only requires 1 IH
only 3 larval stages
MOT is through skin penetration of cercaria
Unique feature of adult male and female schistosome
they copulate for life
Unique feature of adult male schistosome
presence gynecophoral canal / gynecophoric canal
Canal where female is positioned
Assists in sperm transfer
Used for copulation
gynecophoral canal / gynecophoric canal
ingest RBC and absorb nutrients in blood for survival, that’s why they are parasite
schistosomes
Predominant schistosome specie in the philippines
Schistosoma japonicum
T OR F
Eggs alone is sufficient to identify the Schistosomes up to the species level
TRUE
Unique feature of eggs of schistosome
Presence of spines
Differences of species of schistosome
S. japonicum - small lateral spine (knob-like protruberance)
S. mansoni - Large lateral spine
S. haematobium - Large terminal spine
SAmple of choice for Schistosome
still the stool EXCEPT for S. haematobium because it is the urine
S. mansoni and S. japnocum cases are found in
africa
what is the infective stage of schistosome
cercaria larvae
Once the cercaria penetrates the skin and removes its tail then it is called
schistosomule