Trematodes Flashcards
The infective stage is_____
EXCEPT Schistosomes
metacercariae
Classification of Medically Important Trematodes
Phylum Platyhelminthes
Class Trematoda
Subclass Digenea
Classification of Ova
• Mature
Clonorchis
Heterophyids
Opisthorchis
Classification of Ova
Immature
• Fasciola
• Fasciolopsis
• Echinostoma
• Paragonimus
• Schistosoma
General Life Cycle of Trematodes
Larvae
MS. RC Muñoz
Miracidium
Sporocyst
Redia
Cercaria
Metacercaria
Classification Based on
Location in Man
(Blood Flukes)
(Intestinal Fluke)
(Liver Flukes)
(Lung Flukes)
Blood Flukes
Schistosoma japonicum
Schistosoma mansoni
Schistosoma haematobium
- Skin penetration of cercaria
- Schistosomiasis japonicum or
Oriental schistosomiasis
Schistosoma japonicum
Intestinal Flukes (FEAH)
- Fasciolopsis buski (Giant Intestinal Fluke)
- Echinostoma ilocanum
- Artyfechinostomum malayanum
- Heterophyid Group
- ingestion of metacercaria on waterplants
Fasciolopsis buski (Giant Intestinal Fluke)
(Fasciolopsiasis)
Fasciola hepatica (Sheep Liver Fluke)
- ingestion of metacercaria from snails
Echinostoma ilocanum
(Echinostomiasis)
- ingestion of snail with infective stage (snail: Bullastra cumingtiana)
Artyfechinostomum malayanum
- ingestion of metacercaria from fishes
Heterophyid Group
(Heterophyidiasis)
Heterophyid Group
• H. heterophyes
• M. yokogawai
• H. taichui
• H. yokogawai
Liver Flukes (FCO)
- Fasciola hepatica (Sheep Liver Fluke)
- Clonorchis sinensis (Chinese Liver Fluke)
- Opisthorchis felineus (Cat Liver Fluke)
- ingestion of metacercaria in fish
Clonorchis sinensis (Chinese Liver Fluke)
(Clonorchiasis)
- ingestion of metacercaria in fish
Opisthorchis felineus (Cat Liver Fluke)
(Opisthorchiasis)
Lung Flukes
- ingestion of metacercaria from crabs
- Paragonimus westermani (Oriental Lung Fluke)
(Paragonimiasis)
BLOOD FLUKES
Schistosome species
Schistosoma japonicum : Oriental blood fluke
Schistosoma haematobium: Visceral blood fluke
Schistosoma mansoni: Manson’s blood fluke
Parasitizes portal vein and its branches
Each female fluke deposits 500-2000 immature eggs/day
Schistosoma japonicum
Schistosoma japonicum in eternal copula
• Males have a _______ which receives the female during copulation
gynecophoral canal
S japonicum ova
• Ovoidal, rounded or pear-shaped
• Thin shell
• Pale yellow
• Curved hook / spine or lateral knob
• Laid in the multicellular stage and embryonate within 10-12 days
Schistosome Miracidium
• Hatches from the egg in slightly
alkaline clean water with a temp.
between______-_____
• Free swimming ciliated embryo liberated from the egg
• Phototactic
• Infect snails
25 oC to 31oC
Schistosome
Emerges from daughter sporocysts
Escapes from the snail
Has a body and a forked tail
Infects man by skin penetration
Cercaria
Schistosome
• Mother ______ develop from miracidium within the snail
Daughter sporocyst develops
from mother sporocyst
________ develop from daughter sporocyst
Sporocysts and Cercaria
Develops from cercaria after skin penetration
Adapted to survive in serum or physiologic saline at 37 °C
• Enter the pleural cavity—diaphragm— peritoneal space—penetrate the liver to reach the intrahepatic portions of the portal vein
Schistosomule
Schistosoma manson
Ova
With Lateral spine
Schistosoma haematobium
Ova
• Note the terminal spine
• Eliminated with urine
Blood Flukes: Diagnosis Schistosomiasis
Rectal biopsy
Stool Examination Techniques
• Merthiolate-lodine Formalin
Concentration Technique (MIFC)
• Kato Katz Technique
Immunodiagnosis
Sensitive for moderate and heavy infections
Not adequate for light infections (less than 10 eggs/gram of stool)
Merthiolate-lodine Formalin
Concentration Technique (MIFC)
For enumeration of eggs
Most commonly used for evaluating epidemiology, effect of control measures, drug trials
Kato Katz Technique
LIVER FLUKES
Fasciola species
Fasciola hepatica
Sheep Liver Fluke
Temperate Liver fluke
Fasciola gigantica
Giant Liver Fluke
Tropical Liver Fluke
Clonorchis sinensis
(Chinese Liver Fluke)
Opisthorchis felineus (Cat Liver fluke)
Opisthorchis viverrini (South East Asian Liver Fluke)
Adult
Large, flat, brownish 3 x 1.5 cm o With OS and VS
Integument covered with scales; posterior end surface smooth
Alimentary system inverted Y-branched ceca with lateral branches
Fasciola hepatica / Fasciola gigantica
OVA
Operculated 140-150 × 65-90 micra (hepatica) 160-190 x 70-90 micra (gigantica)
Light yellow: bile stained
Transparent with thin double walls
Contain lecithin granules (immature)
Fasciola hepatica / Fasciola gigantica