FINALS_PARA-Trematodes

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Trematodes (Class Trematoda or Digenea)

  • Also known as "flukes"

  • Unsegmented helminth

  • Flat and broad, resembling a leaf or flat fish

Liver Flukes

  • Fasciola hepatica

  • Fasciola gigantica

  • Fasciola lanceolata

  • Chlonorchis sinensis

  • Opistorchis felineus

  • Euretrema pancreaticum

Intestinal Flukes

  • Fasciolopsis buski

  • Heterophyids (Metagonimus yokogawai, Haplorchis yokogawai, Heterophyes heterophyes, Haplorchis taichui)

  • Echinostoma ilocanum

  • Artyfechinostomum malayanum

Lung Fluke

  • Paragonimus westermani

Blood Flukes

  • Schistosoma mansoni

  • Schistosoma japonicum

  • Schistosoma haematobium

  • Schistosoma mekongi

  • Schistosoma intercalatum

General Characteristics (Except for Schistosomes/blood flukes)

  1. Monoecious (hermaphroditic)

    • Possessing male and female reproductive organs

    • Self-fertilization

  2. Primary and secondary intermediate host

    • 1st intermediate host: Mollusk (slugs) - asexual or larval stages

    • 2nd intermediate host: Fish, crabs, or water plants in some other trematodes

  3. Metacercaria is the infective stage

  4. Ingestion is the mode of transmission

  5. Eggs are operculated

    • Eggs are provided with a lid or cap-like structure at the end of the ova

  6. Leaf-like

  7. Has 2 suckers (oral sucker and ventral sucker or "acetabulum")

    • Oral sucker: Surrounding the mouth at the anterior end

    • Ventral sucker: Middle

    • Gonotyl: 3rd sucker (e.g., Heterophyes has a 3rd sucker situated in the genital area)

Schistosomes

  • Dioecious

  • One intermediate host

  • Cercaria

  • Skin penetration

  • Elongated

Other Trematodes

  • Monoecious

  • Two intermediate hosts

  • Metacercaria

  • Ingestion

  • Leaf-like

Fasciola hepatica and Fasciola gigantica

  • Fasciola hepatica

    • Common name: Sheep liver fluke

    • Final host: Sheep

    • 1st intermediate host: Lymnaea philippinensis, Lymnaea auricularia rubiginosa (snails)

    • 2nd intermediate host: Ipomea obscura (kangkong) and Nasturtium officinale (water cress)

    • Habitat: Liver parenchyma, gall bladder

    • Infective stage: Metacercaria

    • Pathology: Fascioliasis, liver rot, liver atrophy, halzoun

    • Laboratory diagnosis: Stool exam, liver biopsy, PCR

    • Drug of choice: Bithionol, triclabendazole

  • Fasciola gigantica

    • Common name: Giant liver fluke

    • Final host: Local cattle, herbivores

    • 1st intermediate host: Lymnaea philippinensis, Lymnaea auricularia rubiginosa (snails)

    • 2nd intermediate host: Ipomea obscura (kangkong) and Nasturtium officinale (water cress)

    • Habitat: Liver parenchyma, gall bladder

    • Infective stage: Metacercaria

    • Pathology: Fascioliasis, liver rot, liver atrophy, halzoun

    • Laboratory diagnosis: Stool exam, liver biopsy, PCR

    • Drug of choice: Bithionol, triclabendazole

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Fasciola lanceolata (Dicrocoelium dendriticum)

  • Common name: Lancet fluke

  • Final host: Sheep, cattle

  • 1st intermediate host: Cionella lubrica, Hellicella candibula (snails)

  • 2nd intermediate host: Formica fusca (ants)

  • Habitat: Biliary tree of herbivores

  • Morphology: Blade-like, lancet-like shaped, aspinous body, large ventral sucking disc

  • Laboratory diagnosis: Stool exam (eggs)

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Clonorchis sinensis, Opistorchis felineus, Opistorchis viverrini

  • Clonorchis sinensis

    • Common name: Oriental liver fluke

    • Final host: Man and other fish-eating vertebrate

    • 1st intermediate host: Genera parafossarulus, Bulimus, Semisulcospira, Alocinma, and Melanoides (snail)

    • 2nd intermediate host: Family Cyprinidae (fishes)

    • Habitat: Liver parenchyma

    • Infective stage: Metacercaria

    • Pathology: Bile duct obstruction, liver carcinoma, gallbladder carcinoma

    • Laboratory diagnosis: Stool exam, serological tests, molecular tests

    • Drug of choice: Praziquantel, albendazole

  • Opistorchis felineus

    • Common name: Chinese liver fluke

    • Final host: Man and other fish-eating vertebrate

    • 1st intermediate host: Genus Bithynia (snail)

    • 2nd intermediate host: Family Cyprinidae (fishes)

    • Habitat: Liver parenchyma

    • Infective stage: Metacercaria

    • Pathology: Bile duct obstruction, liver carcinoma, gallbladder carcinoma

    • Laboratory diagnosis: Stool exam, serological tests, molecular tests

    • Drug of choice: Praziquantel, albendazole

Pathology

  • Periductal fibrosis: Fatigue, weakness, weight loss, altered appetite

  • Gallbladder and liver carcinoma

  • Pancreatitis

Life Cycle

  • Mature eggs/embryonated eggs are passed

Diagnosis

  1. Stool exam

  2. Serologic tests (ELISA, EIA)

  3. Molecular method (PCR)

  4. Cholangiography

Prevention and Control

  1. Health education

  2. Proper waste disposal

  3. Proper food preparation

  4. Fish irradiation at a dose of 0.15 kGy

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Euretrema pancreaticum

  • Morphology:

    • Mature eggs are passed in the feces.

  • Final host:

    • Hogs (pancreatic ducts), sheep, and cattle (biliary ducts)

  • 1st IH:

    • Bradybaena similaris, Macrochlamys indica (snails)

  • 2nd IH:

    • Technomyrmex deterquens (ants)

  • Habitat:

    • Pancreas, duodenum, biliary duct

  • Morphology:

    • Larger oral sucker, 2 notched testes, 1 notched ovary

  • Laboratory diagnosis:

    • Stool exam (eggs)

  • Eggs:

    • Similar to F. lanceolata, thick-shelled and dark brown

  • Pathology:

    • Destruction of the pancreas, chronic granulomatous pancreatitis, enlargement of the pancreas

Fasciolopsis buski

  • Morphology:

    • Macroscopic in preserved specimen

    • Average size: 5 cm by 1.5 cm

  • Common name:

    • Pancreatic fluke

  • Final host:

    • Hogs (pancreatic ducts), sheep, and cattle (biliary ducts)

  • 1st IH:

    • Bradybaena similaris, Macrochlamys indica (snails)

  • 2nd IH:

    • Technomyrmex deterquens (ants)

  • Habitat:

    • Pancreas, duodenum, biliary duct

  • Morphology:

    • Larger oral sucker, 2 notched testes, 1 notched ovary

  • Laboratory diagnosis:

    • Stool exam (eggs)

  • Eggs:

    • Similar to F. lanceolata, thick-shelled and dark brown

  • Pathology:

    • Destruction of the pancreas, chronic granulomatous pancreatitis, enlargement of the pancreas

Giant intestinal fluke

  • Common name:

    • Giant intestinal fluke

  • Final host:

    • Man

  • 1st IH:

    • Semetina spp., Hippeutis spp., Gyraulus spp. (snails)

  • 2nd IH:

    • Trapa (water caltrop), Eichhornia (water hyacinth), Eliocharis tuberosa (water chestnut), Zizania (water bamboo)

  • Habitat:

    • Small intestine (duodenum and jejunum)

  • Morphology:

    • Largest intestinal fluke, flesh-colored, larger ventral sucking disc, no cephalic cone

  • Laboratory diagnosis:

    • Stool exam (operculated eggs)

  • Eggs:

    • "Hen's egg shape", yellowish brown, small operculum, resembles F. hepatica (no shoulders)

  • Pathology:

    • Fasciolopsiasis

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Echinostoma ilocanum (Eupharyphium ilocanum)

  • Common name:

    • Garrison's fluke

  • Final host:

    • Hogs (pancreatic ducts), sheep, and cattle (biliary ducts)

  • 1st IH:

    • Gyraulus convexiusclus and Hippeutis umbilicalis (snails)

  • 2nd IH:

    • Pila luzonica (kuhol), Vivipara angularis ("susong pampang")(snails)

  • Habitat:

    • Small intestines

  • Morphology:

    • Two-lobed testes, oviviparous

  • Laboratory diagnosis:

    • Stool exam

  • Eggs:

    • Straw-colored, less prominent cephalic operculum than Fasciola, immature when released

  • Characteristic feature:

    • Crown of spines on the disk surrounding the oral sucker

  • Echinostoma means spiny mouth

Heterophyes heterophyes

  • Common name:

    • Von Siebold's fluke, Heterophyid fluke

  • Final host:

    • Man

  • 1st IH:

    • Pironella conica (snails)

  • 2nd IH:

    • Mugil cephalus (fish)

  • Habitat:

    • Small intestines

  • Morphology:

    • Smallest trematode, pear-shaped/avocado-shaped with genital sucker (gonotyl - 3rd sucker)

  • Laboratory diagnosis:

    • Stool exam (eggs)

  • Eggs:

    • Embryonated when released, resembles C. sinensis ova, oviparous

  • Pathology:

    • Heterophyiasis --> can be fatal (migration of eggs to the heart or brain causing granuloma)

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Paragonimus westermani

  • Common name:

    • Oriental lung fluke, pulmonary distomiasis

  • Final host:

    • Man

  • 1st IH:

    • Brotia asperata (Antemelania asperata) (snail)

  • 2nd IH:

    • Sundathelphusa philippina, Parathelpusa mista, and P. grapsoides (crab)

  • Habitat:

    • Lungs

  • Infective stage:

    • Metacercaria

  • Pathology:

    • Paragonimiasis

  • Laboratory diagnosis:

    • Sputum exam, serologic test, x-ray exam, stool exam

  • Drug of choice:

    • Praziquantel

  • Paragonimus siamensis:

    • Identified only in cats

    • Only parasite that can be isolated in the lungs

  • Morphology:

    • Oval, yellowish-brown, thick-shelled egg

    • Has a flattened but prominent operculum

    • Has thickened abopercular portion

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Schistosoma spp.

  • Blood flukes

  • Dioecious - female and male reproductive organs are in separate parasites

  • Presence of gynecorphoral canal or groove - holds the male penis during copulation

  • In perpetual copulation

  • Ova is non-operculated

  • Infective stage: cercaria

  • Species:

    • Schistosoma japonicum

    • Schistosoma mansoni

    • Schistosoma haematobium

    • Schistosoma mekongi

  • Cercaria

Schistosoma intercalatum

  • Parameter:

    • S.japonicum

    • S.mansoni

    • S.haematonium

  • Common name:

    • Oriental blood fluke

    • Mansoni blood fluke

    • Bladder fluke, vesical blood fluke

  • Habitat:

    • Superior mesenteric veins of the small intestines

    • Inferior mesenteric veins of the small intestines extending to the colon and rectum

    • Vesical, prostatic uterine venous plexuses

  • IH - all snails:

    • Oncomelania hupensis quadrasi

    • Biomphalaria and Australorbis

    • Bulinus and Physopsis

  • Pathology:

    • Oriental schistosomiasis, katayama fever, snail fever, swamp fever

    • Intestinal bilharziasis

    • Urinary bilharziasis, Egyptian hematuria

  • Ova:

    • Lateral knob (small lateral spine)

    • Prominent lateral spine

  • Preferred specimen:

    • Stool - S.japonicum, S.mansoni

    • Urine - S.haematonium

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Schistosoma spp.

  • Morphology:

    • MOT: Skin penetration

  • Pathology:

    • Early Schistosomiasis:

      • Itching, chills, and fever

    • Colonic Schistosomiasis:

      • Deposition of eggs in the colon (dysentery or diarrhea)

    • Hepatosplenic Schistosomiasis:

      • Most serious consequence

      • Characterized by hepatosplenomegaly and ascites

    • Pulmonary Schistosomiasis:

      • Larval migration to the lungs

    • Cerebral Schistosomiasis:

      • Meningoencephalitis, headache, confusion, lethargy, and coma

  • Schistosomal Cercarial Dermatitis:

    • Swimmer's itch

    • Gulf coast itch

    • Clam digger's itch

    • Cercarial itch

  • Diagnosis:

    • Stool exam

    • Immunodiagnosis:

      • Intradermal test

      • IHA

      • Circumoval Precipitin Test (COPT)

      • ELISA

    • Faust-Meleney Egg Hatching Technique

  • Prevention and control:

    • Chemotherapy

    • Health education

    • Control of Oncomelania snails

    • Chemical contr