Order Plathyhelminthes (Class: Trematoda or Digenea)

Specie Intestinal Species Liver Species Lung Species Blood Species

SN Fasciolopsis buski Heterophyes Metagonimus Fasciola hepatica Clonorchis Paragonimus Schistosoma Schistosoma Schistosoma
heterophyes yokogawai sinensis westermani mansoni japonicum haematobium
CN Large Intestinal Heterophyid Fluke Yokogawai’s Fluke Sheep Liver Fluke Chinese Liver Oriental Lung Fluke Manson’s Blood Blood Fluke Bladder Fluke
Fluke Fluke Fluke
Habitat Small intestine Liver or Bile ducts Lung/Brain/Liver Bloodstream
DH Pigs, Fish-eating mammals (pelicans), Man Herbivorous Man Man Mammalian animals
Man(accidental) mammals,
Man(accidental)
RH Rabbit, Pigs, Dogs Birds, Dogs, Cats Sheep, Cattle Fish-eating Pigs/ Monkeys Monkeys, cattle and other livestock, rodents, dogs, cats
mammals(dogs,
cats, rats)
1st IH Snail -Snails, fresh brackish and salt water Snail (Lymnaeidae) Snail Snail Biomphalaria&Aus Onchomelania Bulinus&Physopsis
-Segmentina sp. (Philippines) : H. taichui and Procerovum - - Bulinusfuchsiana - Brotiaasperata tralorbis
-Hippentis sp. calderoni (brakish water snails), Melania Lymneaphilippinensis
juncea and Thiara riquetti

2nd IH Freshwater -Fish (scales, muscles, fin tails or grills) -Morning glory or Fresh water Talangka
vegetation Kangkong (Ipomea shrimp -
-seed pods of water obscura) Fish: Sundathelpusaphilippina
caltrop:
-Watercress Ctenopharyngodo /
Trapabicornis or
(Nasturtium nnidellus Parathelpusagrapsoides
Trapanutans
-bulb of a officinale)
freshwater
chestnut:
Eleocharistuberosa
IS Metacercariae (on Metacercariae (in fish) Metacercariae (on Metacercariae Metacercariae Schistosomule larvae
water plant ingested water plant ingested (salted, dried, or
by human or pig) by human or sheep/ pickled fish)
cattle)
MOT Ingestion Ingestion Ingestion Ingestion Ingestion Skin penetration of cercariae
(source) (contaminated (contaminated undercooked fish) (contaminated (contaminated (consumption of
aquatic/ water undercooked liver) undercooked, undercooked crayfish or
plants) salted, dried or crab)
pickled fish)

Egg/ Ova -128 – 140 um by 78 -30 by 15 um -128 – 140 um by 78 -30 by 15 um -78 – 120 um long; 45 – -Oblong -roundish -Oblong
– 85 um (large) - developing miracidium – 85um -Developed 60 um wide -Developed -Developed -Developed
-oblong/ oval -Operculated - oblong miracidum -Oval Miracidium Miracidium Miracidium
 -Undeveloped -Indistinguishable due to similarities of -Undeveloped -Operculated -Undeveloped -Large; laterral -Large; later (but -Large; terminal
miracidium Clonorchis sinensis egg miracidium (Thickened rim) miracidium (thin, difficult to see)
-Operculated -Shoulder (discrete/ distinct) -Operculated -Shoulder smooth shell)
-Elongated -Lack of small knob -No cephalic cone -Small knob -opercularim (shoulder)
-Heterophytes (thick shell) -Yellowish to opposite surrounds the
-Metagonimus (thin shell) brownish operculum operculum; terminal
-Yellowish brown shell thickening end
operculum

Adult Large trematode, 1.0 by 0.5 mm Ant. Cephalic cone, Gray, tapering Reddish brown, cuticle Vein (surround Vein (surround Vein (surround
elongated oval in Pyriform shouldered anteriorly, spinous intestinal tract) intestinal tract) bladder)
shape, no cephalic Grayish in color appearance rounded
cone/ shoulder Protected by outer layer of fine scaly posteriorly leaf-shaped, flattened worms
spines round and elongated
1.5 by 0.5 mm
Pyriform
Tapers at anterior end and round at
posterior end
Tiny layer of scaly spines, heavy over
anterior end
Sucker Oral is about ¼ of Oral very small and Large ventral sucker 2 small suckers Ventral is smaller Oral and ventral equal
ventral ventral very large right to the midline EQUAL size than oral
Dx Stage Eggs in stool Eggs in stool Eggs in stool Eggs in stool Eggs in sputum Eggs (stool) Eggs (urine)
Duodenal contents Eggs in stool (rare,
or bile sputum swallowed)
Surgery (recovery of
adult worm)
Diagnosis -Stool -Stool – Kato Thick method, FECT -Stool -Stool Radiographs, ova in Stool or recal Stool or recal biopsy Concentrated urine
-Eggs -Polymerase chain reaction (PCR) -Eggs -duodenal sputum, stool or less biopsy specimen specimen specimen
-Symptoms/travel - identification is difficult to egg -Symptoms/travel aspirates frequently in aspirated
history appearance similarities of parasites and history -adults removed material from abcesses
C. sinensis. -Western blot during surgery or or pleural effusions
-ELISA autopsy procedure
-Computed -ELISA
tomography (CT) - Enzyme
-ERCP imuunoassay (EIA)
-Sonography -coproovoscopy
-PCR
Life Cycle -Unembryonated -Unembryonated eggs(fully developed -Unembryonated -Metacercariae -Human infection
 eggs(feces) miracidium passed in feces) eggs(feces) (ingestion of (consumption of
-Embyronated -Snails host (penetrates intestine) in tissue- -Embyronated contaminated undercooked crayfish or
eggs(water) Sporocysts, Rediae, Cercariae) eggs(water) undercooked fish) crab)
-Miracidia hatch, -cercariae released from snail -Miracidia hatch, -Adult maturation -Immature flukes (in
penetrate snail -Metacercariae (ingestion of contaminated penetrate snail occurs in the liver pairs), migrate through
-Snail undercooked fish) -Snail -Adult worms intestinal wall
tissue(Sporocysts, -Metacercaria excyst in small intestine tissue(Sporocysts, reside in bile ducts -Lung tissue
Rediae, Cercariae) -Adult in small intestine Rediae, Cercariae) -Snail (Miracidia, -Infection brain/ liver
- Cercariae - Cercariae encysts Sporocysts,
-Metacercariae (water plants) Rediae, Cercariae)
(human or pigs) -Metacercariae
-Excyst in (sheep or cattle)
duodenum -Excyst in duodenum
-Adults in small -Adults in hepatic
intestine biliary ducts

Epidemiology -Far East (including -Africa (Near East -Japan, Siberia, -Central and Latin -Far East(Endemic) -Asia Africa Far East: China, Africa
parts of China, and Far East): China, Philippines, America -India (1st record in -Africa Puerto Rico Indonesia, Middle East (Iran,
Taiwan, Vietnam, Taiwan, Philippines, Spain Greece and -Philippines (South 1874) -India West Indies Philippines Iraq, Saudi Arabia)
others) Korea, Japan, Israel Balkans Cotabato) in 2007 -Southeast Asia: -Central and South Central and South (endemic) but not
-Endemic: Southeast and Egypt -Asia: Iran (Gilan (Hong Kong, America, Parts of the America includes Japan
Asia, China, Korea, Province and Caspian Thailand, Korea , U.S. (Human disease
and India but not in Sea) China, Japan & occur)
Philippines (but -Europe: Vietnam) (case of
acquired by Filipinos France(endemic), cholangiocarcinom
abroad) Spain, Potugal, USSR as in 1956) –
endemic
Pathology - Fasciolopsiasis: -Heterophyiasis/ Metagonimiasis: -Fascioliasis: (sheep -Clonorchiasis: -Paragonimiasis Schistosomiasis (bilharziasis, swamp fever)
Inflammation Chronic mucous diarrhea liver rot) intense (pulmonary distomiasis): Inflammation at penetration site
Ulciration Eosinophilia acute or invasive proliferation of cough, hemoptysis, Acute infection: Abdominal pain, fever, chills, weight loss,
Malabsorption Both parasites may escape intestinal tract phase, chronic or intestinal pulmonary TB cough,bloody diarrhea, eosinophilia., hematuria
Intestinal and migrate to other areas (brain, heart). latent phase epithelium symptoms,
obstruction Granulomas often result. Acute stage: <1 misdiagnosed as PTB Nephrotic syndrome.
traumatic, month of infection, Bladder cancer.
obstructive, toxic chills and fever Salmonella infections.
Swimmer’s itch Katayama’s Disease Bilharziasis (bloody
urine)

Rx Praziquantel (25 Prazinquantel (25 mg/ 3 times/ 1 day) Dichlorophenol Praziquantel Praziquantel Oxamniquine
 mg/ 1 day) (bithionol) (25 mg/kg 3 times/ - 25mg/kg for 3 doses Antimalarial medications:
Triclabendazole (not 2days) (60mg/kg/ for one day Artemisinins – artemether and artesunate
available US) 3 times/1 day) Bithionol Surgery may be necessary when obstructions occur
Albendazole - 15-25mg/kg per day on
(both combination alternate days for a total Praziquantel
is more effective) of 10-15 days
Prevention -Avoid consumption -Avoidance of consuming undercooked fish -Exercising -Proper sanitation Avoidance of consuming
of raw water plants (kinilaw) (especially in areas procedures undercooked crab/ Antihelminthic chemotherapy with praziquantel:
or contaminated -Proper fecal disposal known to harbor -Avoidance of crayfish Low cost
water -Control of reservoir host populations if reservoir hosts): raw/undercooked Few side effects
-Washing of plants physically and economically impossible Proper human fecal fish and shrimp Rapid results
to remove disposal
metacercariae Sanitation practices WHO recommendations: Mass treatment (high and low
- Boiling them to kill -Controlling: prevalence areas) includes children
the parasite Snail population
-Swamp and ponds -Avoid consumption
where aquatic of raw water plants
plants are or contaminated
cultivated should be water
protected from
pollution.
Notes -Genus: Sgementina -Philippines (28 species of fish harboring -Large digenetic -Small digenetic
or Hippeutis metacercaria and 21 heterophyid species) trematode trematodes
-Family: Fasciolidae -Family:
-F. hepatica Opisthorchiidae
(temperate liver -classified by the
flukes) in 1523 International
-F. gigantic (tropical Agency for
liver fluke) in 1760, Research on
autopsy in female in Cancer(IARC) as
Berlin, Germany. porbable
-Faciola spp. In carcinogen
Philippines (L.
philippinensis/ L.
auricularia
rubiginosa)