Trematodes Flashcards
Trematodes Adult Worms
- Usually flat
- Elongated
- Leaf shaped
- Two cup-shaped muscular suckers
- Oral sucker
- Ventral sucker used for attachment
Hermaphroditic Fluke
- Bisexual
- Highly branched reproductive organs
- Paragonimus westermani
- Fasciola hepatica
- Clonorchis sinensis
- Fasciolopsis buski
- Heterphyes heterophyes
- Metagonimus yokagawai
Unisexual Adult Worms
- Both male and female
- Schistosoma mansoni
- Schistosoma japonicum
- Schistosoma haemtobium
Trematodes Life Cycle
1) Adult lives in specific organs or blood
2) Eggs are found in particular specimen depending on species
3) Eggs contaminate environment
4) Eggs contain larvae (mirachidium)
5) Mirachidium infects specific snail species
6) Mirachidium forms sporocyst, which then develops into cercariae
7) Cercariae are free swimming
Sites Eggs are found
1) Sputum - lung fluke (P. westermani)
2) Feces - intestines (S. mansoni, S. japonicum, F. buski, H. heterophyes, F. hepatica, C. sinensis)
3) Urine - bladder (S. haematobium)
Cercariae pathways
1) Schistosomes (species found in blood)
- Cercariae emerge from snail and penetrate skin of humans
2) In F. buski and F. hepatica
- Encyst attaches to water plants and eaten by humans
3) H. heterophyes, C. sinensus, & P. westermani
- Enters the second intermediate host (fish or crabs) which is eaten by humans
Trematodes Pathology
Lesions which depend upon location, number of adult worms, and effect eggs and metabolic products have on host
Paragonimus westermani Distribution
Found in far east
Japan, China, Micronesia, New Guinea, Korea, Vietnam, Thailand, Cambodia, India, and Philippines
Paragonimus westermani Symptoms
Chest pain
Cough
Blood tinged sputum (appears pepper-like and blood streaked)
Paragonimus westermani Adult
Encyst in the lung
Frequently in pairs
1 mm x 5 mm
Paragonimus westermani Egg
85 x 55 mm
Terminal shell thickening
Shouldered operculum
Operculum has rim
Fasciola hepatica Distribution
Sheep and cattle-raising countries
Fasciola hepatica Symptoms
Causes liver cirrhosis
Fasiola hepatica Adult
35 mm x 15 mm
Fasiola hepatica Egg
150 x 90 um
Operculated
Clonorchis sinesis Distribution
Found in far east
Japan, Korea, Vietnam, and China
Cloronochis sinesis Symptoms
Inflammatory changes
Feeding of adult in biliary passages
Jaundice due to bile duct pathology
Diarrhea
Abdominal pain
Clonorchis sinesis Adult
Measures 19 mm x 3.5 mm
Clonorchis sinesis Egg
30 um x 16 um
Small terminal knob
Thickened rim around operculum - “shouldered operculum”
Clonorchis sinesis Diagnostic Stage
Egg in stool
Fasciolopsis buski Distribution
China, India, Vietnam, and Thailand
Fasciolopsis buski Adult
20-30 mm x 10 mm
Fasciolopsis buski Pathology
- Mucosal ulcers
- Pain
- Nausea
- Diarrhea
Fasciolopsis buski Egg
Same as F. hepatica
Cannot differentiate between the two
Fasciolopsis buski Infectious Stage
Ingestion of water chestnuts contaminated with metacercaria
Fasciolopsis buski Diagnostic Stage
Egg in stool
Schistosoma japonicum Distribution
Far East
Schistosoma japonicum Common Name
Oriental Blood Fluke
Schistosoma japonicum Pathology
- Granuloma of liver or intestines
- Cirrhosis
- Most pathogenic
Schistosoma japonicum Egg
80 x 60 um
Small indistinguishable lateral spine
Schistosoma japonicum Diagnostic Stage
Egg in stool
Schistosoma mansoni Distribution
Africa, Middle East, and South America
Schistosoma mansoni Pathology
Bilharzia
Granuloma of liver, intestines, and bladder
May cause cirrhosis
Schistosoma mansoni Egg
160 um x 80 um
Prominent lateral spine
Schistosoma mansoni Diagnostic Stage
Egg in stool
Schistosoma haematobium Distribution
Nile River Valley, African, Middle East
Schistosoma haematobium Pathology
Squamous cell carcinoma of bladder
Schistosoma haematobium Egg
160 um x 80 um
Terminal spine
Schistosoma haematobium Diagnostic Stage
Eggs in urine
Schistosoma dermatitis Distribution
Cosmopolitan
Schistosoma dermatitis Pathology
Dermatitis (inflammation and localized edema)
Schistosoma dermatitis Infectious Stage
Cercariae penetration of skin
Schistosoma dermatitis Diagnostic Stage
Rash after swimming
Schistosoma dermatitis Common Name
Swimmer’s Itch
Clam Digger’s Itch
Whirl Pool Dermatitis
Paragonimus westermani Common Name
Oriental Lung Fluke
Paragonimus westermani Infectious Stage
Ingesting raw crayfish with metacercariae
Paragonimus westermani Diagnostic Stage
Eggs in sputum
Fasciola hepatica Common Name
Sheep Liver Fluke
Fasciola hepatica Infectious Stage
Ingesting watercress contaminated with metacercariae
Fasciola hepatica Diagnostic Stage
Egg in stool
Travel history
Clonorchis sinesis Common Name
Chinese Liver Fluke
Clonorchis sinesis Infectious Stage
Ingesting under cooked fresh water fish contaminated with metacercariae