Trematode Infections Flashcards
A genus of parasitic blood flukes that infect birds and mammals, including humans.
Schistosoma
Name the five species of medically important Schistosoma.
S. japonicum
S. mansoni
S. haematobium
S. mekongi
S. intercalatum
Known to be the predominant species in the Philippines.
S. japonicum
Common name for Schistosoma japonicum
Oriental blood fluke
Intermediate host of S. japonicum
Oncomelania snails
The S. japonicum life cycle involves an intermediate ______ host and a definitive _____ host.
snail & mammalian respectively
The first larval stage that emerges from the egg in fresh water
Miracidium
Emerges from the miracidium as a sac-like structure containing the larva
Sporocyst
The reproduction type of sporocysts that can later give rise to free-swimming cercariae after 60-70 days.
asexual
Intermediate larval stage occurring in the sporocyst
Rediae
Final stage of development occuring in the snail; motile by means of a tail; infective stage of all schistosomes
Cercariae
Encysted form occurring in the 2nd intermediate host
Metacercariae
MOT of S. japonicum
Skin penetration
This is where S. japonicum matures
Portal vein
S. japonicum egg deposition usually begins from the _____ to the _____ day after cercarial penetration.
A. 21st to the 24th
B. 24th to the 27th
C. 27th to the 30th
B. 24th to the 27th day
The definitive hosts of S. japonicum
dogs, pigs, cats, carabaos, cows, rodents, and monkeys
Its egg is ovoid, round or pear-shaped, and is pale yellow in color. It has a thin shell onto which residual tissue or red cells may be adherent.
S. japonicum egg
Its egg has a curved hook or spine that may be observed near one of the polar ends if the egg is properly oriented.
S. japonicum
Its eggs hatch only in clean fresh water with sufficient oxygen.
S. japonicum
S. japonicum eggs will not hatch in salinity greater than ___ or at mammalian body temperature
A. 0.3%
B. 0.5%
C. 0.7%
C. 0.7%
A temperature between ____ to ____ degree celsius is ideal for the hatching of S. japonicum eggs.
A. 25 to 31%
B. 26 to 32%
C. 27 to 33%
A. 25 to 31%
All factors influence the infection of snails by miracidia except:
A. Age of snails & the miracidia
B. Number of miracidia per snail
C. Length of contact time
D. Water flow
E. Turbulence
F. NOTA
F. NOTA
Its cercaria has a body and a forked tail, an oral sucker which occupies the anterior end of the body, and a small ventral sucker.
S. japonicum
O. h. quadrasi (Oncolomelania hupensis quadrasi) is more active and mobile at ______
A. day
B. night
B. night
After skin penetration, the cercaria loses its tail and transform into a ______________.
Schistosomule
Trematodes that are dioecious (male & female reproductive organs are separate)
schistosomes
T or F. Schistosomes have a complete digestive system and an excretory system made up of flame cells.
False. Schistosomes have an incomplete digestive system.
Ingested by schistosomes that possess a protease (hemoglobinase) that breaks down globulin and hemoglobin.
RBCs
Easy fatigability, respiratory symptoms, arthralgias, myalgias, malaise, eosinophilia, fever, and abdominal pain which has been termed as “snail fever”.
Katayama fever/Katayama syndrome
S. japonicum egg deposition occurs in what organs?
Liver, intestines, lungs, and much less frequently in the CNS
The most serious consequence of chronic schistosomiasis
Hepatosplenic disease
Diagnostic stage of S. japonicum
Embryonated egg
T or F. Stool examinations for S. japonicum can give negative results even in active infection.
True
T or F. Schistosome eggs can be recovered by rectal or liver biopsy
True
The preferred technique and considered the most suitable for quantification of eggs.
Kato-Katz
Treatment for schistosomiasis
Praziquantel
Prevention and control of schistosomiasis in areas of high prevalence and transmission
mass chemotherapy using praziquantel
An operculated fresh water amphibious snail with separate male and female sexes.
O. h. quadrasi
Refers to an infection of humans and other mammals by trematodes of the genus Paragonimus.
Paragonimiasis
There are ____ known species of Paragonimus, and ____ are reported to cause infections in humans.
A. 40 & 10 respectively
B. 40 & 8 respectively
C. 40 & 6 respectively
D. 40 & 4 respectively
C. 40 known species and 6 are reported to cause infections in humans.
Common name for Paragonimus westermani
Oriental lung fluke
The second intermediate host of P. westermani
Mountain Crabs
(Sundathelphusa philippina)
This adult fluke resembles a coffee bean. It is rounded anteriorly and slightly tapered posteriorly.
Lung fluke
1st intermediate host of P. westermani
Snail
(Antemelania asperata & Antemelania dactylus)
MOT of P. westermani
Ingestion of raw or insufficiently cooked crabs harboring metacercariae
These have been found to play an important role in the development of young parasites because of their involvement in the metacercarial excystment, tissue invasion, and immune modulation of the host.
Cysteine proteases
Habitat of P. westermani
Lungs
The following are symptoms of paragoniamiasis, except:
A. Hemoptysis
B. Chronic cough
C. Chest pain
D. Dyspnea
E. NOTA
E. NOTA
T or F.
P. westermani may migrate into the cranial cavity and result in hemorrhage
True
Diagnosis for P. westermani.
Sputum examination
DFS
Chest radiographs
Serodiagnostics (ELISA, IB)
Molecular tests (PCR)
“Chinese vase egg”
P. westermani
Its egg may appear macroscopically in sputum as reddish-brown flecks resembling iron filings; operculated with shoulders and thick abopercular shell
P. westermani
Which among the following are definitive hosts of P. westermani
A. Man
B. Wolf
C. Monkey
D. Only A & B
E. AOTA
F. NOTA
E. AOTA
Drug of choice for P. westermani
Praziquantel and/or Triclabendazole
This fasciolid digenetic trematode is the largest intestinal fluke of humans and pigs.
Fasciolopsis buski
MOT of fasciolopsis buski
Ingestion of encysted metacercariae from aquatic plants
Common name of F. buski
Giant intestinal fluke
First IH of F. buski
Snail
(Segmentina or Hippeutis)
Second IH of F. buski
Vegetation
- Water caltrop (Trapa bicornis)
- Water chestnut (Eliocharis tuberosa)
- Morning glory/Kangkong (Ipomea obscura)
- Lotus (Nymphaea lotus)
- Bamboo shoots (Zizania)
DH of F. buski
pigs and humans
Symptoms of F. buski
Epigastric pain
Nausea
Diarrhea
edema
Diagnostic stage of F. buski
Detection of parasite eggs in stool
Treatment for F. buski
Praziquantel
Digenetic trematodes characterized by a collar of spines around their oral suckers.
Echinostomids
A horseshoe-shaped collar, bearing one or two rows of straight spines, which surrounds the dorsal and lateral sides of the oral sucker.
Echinostoma
MOT of Echinostoma ilocanum & Artyfechinostomum malayanum
Ingestion of metacercariae encysted snails
DH of E. ilocanum and/or A. malayanum
humans
dogs
cats
rats
pigs
Common name of E. ilocanum
Garrison’s fluke
1st snail IH of E. ilocanum
Gyraulus convexiusculus
Hippeutis umbilicalis
2nd snail IH of E. ilocanum
Pila luzonica (kuhol)
Vivipara angularis (susong pampang)
2nd snail IH of A. malayanum
Lymnaea cumingiana
Ampullarius canaliculatus
1st IH of A. malayanum
unknown
The egg of ______ is straw-colored, operculated, and ovoid whereas ______’s egg is larger, golden brown in color, and operculated.
E. ilocanum & A. malayanum respectively
Symptoms of Echinostoma
Inflammation
Ulceration
Bloody diarrhea
Abdominal pain
Diagnosis of Echinostoma
Detection of eggs in the stool
Treatment for Echinostoma
Praziquantel
MOT of heterophyids
Ingestion of metacercariae encysted in fish
Smallest trematode of man; deadliest trematode
Heterophyes heterophyes
Symptoms of Heterophyid Flukes
Diarrhea
Colicky abdominal pain
Diagnosis of Heterophyid Flukes
detection of eggs in stool using the modified Kato thick method
PCR for low-intensity heterophyid infections
Treatment for Heterophyid Flukes
Praziquantel
Common name of Fasciola hepatica
sheep liver fluke - temperate
Common name of Fasciola gigantica
giant liver fluke- tropical
1st IH of Fasciola spp.
Lymnea philippinensis
2nd IH of Fasciola spp.
Watercress
grass
MOT of Fasciola spp.
Ingestion of raw aquatic vegetation (water chestnuts) with encysted metacercaria or by drinking water with viable metercercariae
What distinguishes F. hepatica and F. gigantica?
cephalic cone
Drug of choice for treating fascioliasis
Triclabendazole or Biothionol as an alternative
Reservoir hosts of Fasciola spp.
Sheep
Cattle
Goat
Refers to the presence of eggs in the stool resulting not from an actual infection but from recent ingestion of infected livers containing eggs.
False fascioliasis (pseudofascioliasis)
Small digenetic trematodes belonging to the family Opisthorchiidae and are parasite of the bile duct and gallbladder of humans and fish-eating mammals.
Clonorchis sinensis,Opisthorchis felineus & Opisthorchis viverrini
MOT of liver flukes
ingestion of the metacercaria of the parasite present in infected raw or undercooked fish —- salted, dried, or pickled fresh water fish
Treatment for Clonorchis, Opisthorcis
Praziquantel
Also known as Vesical Blood Fluke
Schistosoma haematobium
Also known as Manson’s Blood Fluke
Schistosoma mansoni
Used to speciate Schistosome
spine
S. mansoni - conspicuous lateral spine
S. japonicum - inconspicuous/rudimentary lateral spine or knob
S. haematobium - terminal spine
Dermatitis due to skin penetration of cercariae from birds and other mammals
Swimmer’s Itch
