Exercise No. 8b PHYLUM PLATYHELMINTHES Class Trematoda - Monoecious Flukes Flashcards
Leaf-shaped
Fasciola hepatica
Pointed anterior, rounded posterior (“bottle-neck” appearance)
Clonorchis sinensis
Resembles C. sinensis
Opisthorchis felineus and Opisthorchis viverrini
Lancet-shaped
Dicrocoelium dendriticum
Elongate-ovoidal in shape
Fasciolopsis buski
Attenuated at both ends
Echinostoma ilocanum
Narrow anterior, rounded posterior (“pyriform”)
Heterophyes heterophyes
Resembles H. heterophyes
Metagonimus yokogawai
When active: spoonshaped; At preserved state:70-100 x 50-60 pm oval, flattened, coffee-bean-shaped
Paragonimus westermani
Integument: scales vary in size, pattern & distribution, but posterior is aspinose
Fasciola hepatica
Integument: aspinose
-Clonorchis sinensis
-Opisthorchis felineus and Opisthorchis viverrini
-Dicrocoelium dendriticum
Integument: Spinose
Fasciolopsis buski
Integument: with spines and scales
Echinostoma ilocanum
Integument: scales are narrow and closely set, numerous in the anterior
Heterophyes heterophyes
Integument: scale-like spines
Paragonimus westermani
Oral sucker, 0.5 mm
Ventral sucker, 2-3 mm
Uterus, coiled
-
-
-Fasciolopsis buski
Vitellaria, highly branched in the lateral and posterior
Fasciolopsis buski
Vitellaria, medium-sized follicles in posterior % lateral fields
Echinostoma ilocanum
Vitellaria, large, polygonal follicles in each lateral posterior third
Heterophyes heterophyes
Metagonimus yokogawai
.
Genital sucker, armed w/spines
Heterophyes heterophyes
Vitellaria, branched, lateral for the entire length of the body
Paragonimus westermani
Ceca, unbranched
Fasciolopsis buski
Circumoral disk with horseshoe-shaped crown of 49-51 hooks
Echinostoma ilocanum
Ovary, branched
Fasciola hepatica
Ovary, round or lobed
Echinostoma ilocanum
Ovary, subglobose
Heterophyes heterophyes
Metagonimus yokogawai
Ovary, lobed
Paragonimus westermani
Testes, highly dendritic
In tandem in the 2nd & 3rd fourths
Fasciola hepatica
Testes, deeply lobed or branched in tandem in the posterior 3rd fields
Clonorchis sinensis
Testes lobed oblique to each other in the posterior 4th
Opisthorchis felineus and Opisthorchis viverrini
Testes, slightly lobed, oblique to each other
Dicrocoelium dendriticum
Testes, highly dendritic
In tandem in posterior 1/2
Fasciolopsis buski
Testes, lobed
In tandem in posterior 1/2
Echinostoma ilocanum
Testes, ovoid, side by side in the posterior fifth
Heterophyes heterophyes
Testes, ovoid obliquely side by side in posterior 5th
Metagonimus yokogawai
Testes, lobed, oblique to each other or nearly side by side at the posterior third
Paragonimus westermani
Ovoid, hen’s egg- shaped
Fasciola hepatica
broadly ovoid (“old- fashioned electric bulb”)
Clonorchis sinensis
elongate-ovoid, narrower than C. s/nens/sova
Opisthorchis felineus and Opisthorchis viverrini
asymmetrically ovoidal
Dicrocoelium dendriticum
hen’s egg-shaped, identical to F. hepatica, thin, transparent shell
Fasciolopsis buski
straw-colored, ovoid
Echinostoma ilocanum
ovoid, less distinct opercular shoulder
Heterophyes heterophyes
Similar to H. heterophyes
Metagonimus yokogawai
shape varies greatly, some asymmetrical, thick shell
Paragonimus westermani
light yellowish-brown
-Fasciola hepatica
-Clonorchis sinensis
-Opisthorchis felineus and Opisthorchis viverrini
dark brown
Dicrocoelium dendriticum
thin, transparent shell
Fasciolopsis buski
straw-colored
Echinostoma ilocanum
Yellowish-brown to dark golden brown
Paragonimus westermani
small, flat operculum at one end
Fasciola hepatica
convex operculum fits a circular rim of shell, small knob at the abopercularend
Clonorchis sinensis
operculum fits into a thickened rim of shell, minute thickening at the abopercular end
Opisthorchis felineus and Opisthorchis viverrini
broad convex operculum
Dicrocoelium dendriticum
small, slightly convex operculum
Fasciolopsis buski
small operculum
Echinostoma ilocanum
less distinct opercular shoulder
Heterophyes heterophyes
flattened operculum, thickened opercular rim, and abopercular end is generally thicker than the sides
Paragonimus westermani
Ovary central
Schistosoma japonicum
Ovarv anterior half
Schistosoma mansoni
Ovary posterior half
Schistosoma haematobium
Tegument smooth
Schistosoma japonicum
Tegument coarsely tuberculated
Schistosoma mansoni
Tegument slightly tuberculated
Schistosoma haematobium
6-8 testes
Schistosoma japonicum
8-9 testes
Schistosoma mansoni
4-5 testes
Schistosoma haematobium
Lateral knob
Schistosoma japonicum
Lateral spine
Schistosoma mansoni
Terminal spine
Schistosoma haematobium
50-100 ova in uterus
Schistosoma japonicum
1-4 ova in uterus
Schistosoma mansoni
20 - 30 ova in uterus
Schistosoma haematobium
Definitive diagnosis: demonstration of characteristic eggs in feces or aspirated bile from duodenum
Definitive diagnosis: demonstration of characteristic eggs in feces or aspirated bile from duodenum
-Dibothriocephalus latus (Diphyllobothrium latum)
-Clonorchis sinensis
-Opisthorchis felineus and Opisthorchis viverrini
Definitive diagnosis: demonstration of characteristic eggs in feces
Dicrocoelium dendriticum
Echinostoma ilocanum
Definitive diagnosis: demonstration of characteristic eggs in feces of the worms after administration of a purgative or anthelmintic drug
Fasciolopsis buski
Definitive diagnosis: detection of characteristic eggs in feces
Heterophyes heterophyes and Metagonimus yokogawai (The heterophyids)
Definitive diagnosis: detection of characteristic eggs in sputum
Paragonimus westermani
best method of diagnosis for Dibothriocephalus latus (Diphyllobothrium latum)
Microscopic examination
Eggs of [?] are indistinguishable.
F. hepatica and F. buski
Differential diagnosis must be made to differentiate between TRUE INFECTION form SPURIOUS INFECTION.
Dibothriocephalus latus (Diphyllobothrium latum)
result from ingestion of infected herbivore liver harboring the eggs which are passed out in the feces without any morphological changes
SPURIOUS FASCIOLIASIS
The following steps may be performed:
- Ask the patient if he has taken/ included liver in his previous diet.
- Advice him to have a liver-free diet for 2 – 3 days and recollect a stool sample
- Patient’s stool sample is reexamined and, if
(+) eggs in the feces: TRUE INFECTION
(-) eggs in the feces: SPURIOUS INFECTION
Blood picture.
Examination of peripheral blood reveals eosinophilia.
Dibothriocephalus latus (Diphyllobothrium latum)
Serodiagnosis.
a. Antibody detection
b. Antigen detection
Dibothriocephalus latus (Diphyllobothrium latum)
Serological tests such as immunofluorescence, ELISA, immunoelectrophoresis and complement fixation are helpful for detection of specific antibody in light infections.
Dibothriocephalus latus (Diphyllobothrium latum)
ELISA becomes positive within 2 weeks of infection and is negative after treatment.
Dibothriocephalus latus (Diphyllobothrium latum)
is of diagnostic importance during chronic fascioliasis
Antigen detection
Fasciola coproantigen may be detected in stool.
Antigen detection
Dibothriocephalus latus (Diphyllobothrium latum) Imaging
a. Ultrasonography
b. computed tomography (CT) scan
c. endoscopic retrograde cholangiopancreatography (ERCP)
d. percutaneous cholangiography
Detecting moderate to heavy infections:
a. Kato thick smear b. Stoll’s dilution c. Quantitative FECT
Clonorchis sinensis
Eggs do not float in concentrated saline.
Clonorchis sinensis
Eggs of C. sinensis are difficult to differentiate from those of
H. heterophyes, M. yokogawai, and O. felineus species.
Blood examination.
Examination of peripheral blood smear may reveal leukocytosis with eosinophilia.
Clonorchis sinensis
Immunodiagnosis
Several serological tests for antibody detection have been described but extensive cross-reactions limit their utility.
Clonorchis sinensis
Clonorchis sinensis Immunodiagnosis
a. Complement fixation
b. Gel precipitation
c. IHA with a saline extract of etherized worms
d. ELISA
has been reported to be sensitive and specific
IHA with a saline extract of etherized worms
Clonorchis sinensis
Fecal antigen detection
ELISA
Clonorchis sinensis
Intradermal allergic (hypersensitivity) tests
Clonorchis sinensis
Detecting moderate to heavy infections:
a. Kato thick smear b. Stoll’s dilution c. Quantitative FECT
Opisthorchis felineus and Opisthorchis viverrini
Eggs do not float in concentrated saline.
Opisthorchis felineus and Opisthorchis viverrini
Eggs of are difficult to be differentiate on morphological grounds from those of C. sinensis, H. heterophyes, M. yokogawai,.
Opisthorchis felineus and Opisthorchis viverrini
useful for specific identification of O. viverrini
Polymerase chain reaction (PCR)
Similar with Fascioliasis, differential diagnosis must also be performed in order to differentiate true infection from spurious infection which may arise from ingestion of the parasite’s egg in contaminated cattle liver.
Dicrocoelium dendriticum
History of residence in endemic areas suggests diagnosis
Fasciolopsis buski
The eggs of [?] are indistinguishable.
F. buski and F. hepatica
Examination of peripheral blood
Eosinophilia is often present
Fasciolopsis buski
Immunodiagnosis
Serodiagnosis is of no value.
Fasciolopsis buski
first documented in humans in 1987, and has since been reported in Northern and Central Luzon
Artyfechinostomum (Echinostoma) malayanum
In 2005, a study in Siargao Island, Surigao del Norte, showed A. malayanum in [?] of individuals suffering from gastrointestinal disturbance.
11.4%
All infected patients has a history of having eaten [?] prepared raw with coconut milk and lime juice.
snails (kuhol and kiambuay)
Kato Thick method
has a higher sensitivity compared to FECT (31.0% vs. 13.6%)
Heterophyes heterophyes and Metagonimus yokogawai (The heterophyids)
careful inspection of the egg’s features must be observed in order to differentiate it from those of C. sinensis and Opisthorchis species
Kato Thick method,
may be useful as a sensitive diagnostic tool, particularly for low-intensity heterophyid infections
PCR
o stool o gastric washing o abscess o pleural effusions o tissue material
Paragonimus westermani
Serology is of particular importance in eggnegative cases and in cerebral paragonimiasis.
Paragonimus westermani
Parasite-specific immunoglobulin E (lgE) and antiparagonimus antibodies can be detected in serum.
Paragonimus westermani
carried out with a saline extract of adult Paragonimus westermani or other suitable antigen gives an immediate sensitivity reaction in infected persons
Intradermal test
remains positive long after recovery, thereby indicating past infection
Intradermal test
used for the diagnosis indicates an active infection
Complement fixation test
highly sensitive
IHA and ELISA tests
tests become negative within 3-4 months after successful treatment
IHA and ELISA tests
reveals abnormal shadows (nodular, cystic, and infiltrative) in the middle and lower lung fields similar to pulmonary tuberculosis
Chest X-ray
presence of shadows of tunnels and “burrows” in the lung bases resemble bronchiectasis
Chest X-ray
chest
also helps in diagnosis of pulmonary and cerebral lesions
CT scan
“Soap-bubble’’ like appearance may be seen in cerebral cysts
CT scan
Microscopic examination of stool samples to demonstrate characteristic eggs of S. japonicum and S. mansoni may be accomplished by routine parasitologic methods and/or quantitative techniques to determine worm burden; similar to those techniques employed in the diagnosis of helminthiasis.
Examination of stool
Microscopic examination of urine is used to demonstrate characteristic eggs of S. haematobium. This may be accomplished by one of the following methods:
1. Urine sedimentation
2. Urine filtration
Examination of urine
T or F
When schistosome eggs are recovered from either urine or stool, they should be carefully examined to determine viability.
T
T or F
An individual who has undergone successful treatment form schistosomiasis continuously pass out residual eggs which are non-viable, hence may indicate good, previous treatment.
T
On the other hand, the presence of living [?] within the eggs indicates an active infection that may require therapy.
miracidia
At the end of micturition, the [?]contracts facilitating extrusion of eggs deposited in the walls of the bladder.
urinary bladder
The sample should consist of a single terminal urine specimen of at least
10 mL
The viability of the miracidia can be determined in two ways
- Flame cell activity2. Miracidial hatching test
Schistosome miracidia possess primitive excretory cells known as flame cells. If eggs are viable (i.e. containing viable miracidia) the cilia of the flame cells may be seen on a wet smear by using high dry power and are usually actively moving.
Flame cell activity
, the miracidia may be released from the eggs recovered in stool or urine.
Miracidial hatching test
Histopathology
Schistosomiasis may also be diagnosed by demonstration of characteristic schistosome eggs during microscopic examination of biopsy materials obtained from the [?] (for intestinal schistosomiasis), or the [?] (for urinary schistosomiasis).
rectal valve
urinary bladder
Detection of schistosome antigens may be performed using a patient’s [?] (for S. haematobium).
serum or urine
Two circulating antigens related to gut of adult schistosomes:
(1) circulating anodic antigen (CAA)
(2) circulating cathodic antigens (CCAs) can be demonstrated by dipstick assay and ELISA using urine obtained form a suspected individual
The test is very sensitive and specific but is available only in specialized laboratories
Antigen detection
Soluble egg antigens (SEAs) can be demonstrated in serum.
Antigen detection
Several tests have been described to detect specific antibodies in serum samples of infected individuals. The most common are:
I. Circumoval Precipitin Test (COP/COPT)
II. FAST-ELISA (Falcon Assay Screening Test-Enzyme-linked Immunosorbent Assay)
o employed to detect antischistosomal antibodies in patients serum using lyophilized eggs or purified live (viable) eggs identified under the microscope as antigens
Circumoval Precipitin Test (COP/COPT)
The procedure involves reacting 1 drop (about 0.025 ml) of the antigen suspension with 3 drops (about 0.075 ml) of patient’s serum into a well of a slide.
Circumoval Precipitin Test (COP/COPT)
The reaction well is overlaid with a coverslip and incubated at 34 degrees C for 24 hours.
Circumoval Precipitin Test (COP/COPT)
The slide is examined under the microscope for reaction.
Circumoval Precipitin Test (COP/COPT)
The appearance of blebs of precipitate around the eggs is considered as a positive result.
Circumoval Precipitin Test (COP/COPT)
COPT is considered useful in the diagnosis of intestinal schistosomiasis.
Circumoval Precipitin Test (COP/COPT)
This method employs the use of purified , species-specific microsomal antigens of adult schistosome worms to detect antibodies in the patient’s serum.
FAST-ELISA (Falcon Assay Screening Test-Enzyme-linked Immunosorbent Assay)
A positive reaction (greater than 9 units/µl serum) indicates infection with schistosome species.
FAST-ELISA (Falcon Assay Screening Test-Enzyme-linked Immunosorbent Assay)
The specificity of the FAST-ELISA is 99%, and its sensitivity is 99% for S. mansoni, 95% for S. haematobium, and approximately 50% for S. japonicum infection
FAST-ELISA (Falcon Assay Screening Test-Enzyme-linked Immunosorbent Assay)
Abdomen
may show bladder and ureteral calcification in infections with S. haematobium
a. X-ray
may show hydroureter and hydronephrosis in urinary schistosomiasis and hepatosplenomegaly and periportal fibrosis in chronic intestinal schistosomiasis
b. Ultrasonography (USG)
also useful in indirect diagnosis of urinary bilharziasis
c. Intravenous pyelogram (TVP) and cystoscopy
Aside from the three medically significant schistosomes previously mentioned, 2 more schistosome species have been found to infect man. They are:
Schistosoma lntercalatum
Schistosoma mekongi
o was first noted in 1934 in West-Central Africa
Schistosoma lntercalatum
o The eggs are similar to S. haematobium in general shape and in possessing a terminal spine, but are usually longer (140-240 µm), often have an equatorial (central) bulge and are shed in stool, not urine and are acid-fast.
Schistosoma lntercalatum
o It produces few symptoms involving the mesenteric portal system.
Schistosoma lntercalatum
o Diagnosis is established by the detection of the egg in feces and rectal biopsy.
Schistosoma lntercalatum
was first recognized in 1978 in Thailand and Cambodia, along the Mekong river
Schistosoma mekongi
Man, acquires infection in the same way as in S. japonicum, serves as the definitive host together with dogs.
Schistosoma mekongi
The eggs are closely related in morphology to S. japonicum but are generally smaller (50-80 µm by 40-65 µm).
Schistosoma mekongi
They also contain a small, inconspicuous spine and are shed in stool.
Schistosoma mekongi
