Trematodes Flashcards
General characteristics:
Trematoda: Incomplete digestive tract
Mouth, pharynx, and esophagus
Blind-sac intestines (ceca)
Trematoda
Reproductive organs of male and female in one organism or segment
Monoecious
Separate male and female organisms
reproductive organs in one
Dioecious
Cross-fertilization: Most often (when more than one adult is present)
Self-fertilization: When only one organism is present
Fertilization: Internal
Largest subclass
Found in every major organ
Includes all ____ which parasitize man
Hosts: Intermediate, reservoir, and definitive
Trematoda
subclass Digenea
Shape: The body is flattened dorso-ventrally; leaf-shaped
Monozoic: One body part
Trematoda: Flukes
Suckers: Two
Oral sucker: Mouth
Ventral sucker -Acetabulum; hold-fast organ
Trematoda: Flukes
Intermediate hosts
Two: Most members
One: ??
Schistosomes
Operculated: Most members
Non-operculated: Schistosomes
Contains first stage larva: Most
OVA
Trematodes: Flukes
Trematodes: Flukes
Larval stages: 5
Miracidium Sporocyst Redia Cercaria Metacercaria
Larval Stages;
All Trematodes
Hatches in water
Ciliated
Miracidium
Larval Stages:
one or more stages
Sporocyst
Redia
Larval Stages:
Form which completes development in the snail and then leaves
Free swimming
Infective form to man: For dioecious organisms (Schistosomes)
Cercaria
Larval stages:
Encysted cercaria
Infective form to man: For monoecious organisms
Metacercaria
Tegument
Taxonomically important in ______
Described as smooth, finely tuberculated, or grossly tuberculated
Schistosomes
Testes: -Number: Taxonomically important in Schistosomes -Position Para Oblique Tandem
See slide 17
Testes: -Shape Oval Lobate Dendritic or branched
slide 18
Intestinal ceca: -Shape Straight Undulating Branched Rejoined
slide 19
Common name: Lung Fluke
Paragonimus Westermani
Geographical distribution: Asia, South America, North America, Africa and India
Paragonimus Westermani
Pathogenesis: Tuberculosis-like symptoms Lung damage: Fibrosis Migratory tissue damage Extra pulmonary abscesses
Paragonimus Westermani
Acquired through eating undercooked crustaceans carrying metacercaria
Paragonimus Westermani
Causes chronic coughing, bloody sputum, fibrotic lung damage.
Paragonimus Westermani
Diagnosis: Eggs found in sputum and feces
Paragonimus Westermani
Common name: “Sheep liver fluke”
Fasciola Hapatica
Pathogenesis
Mechanical destruction of liver tissue (stimulates growth with proline)
Fibrosis
Fasciola Hapatica
Sheep liver fluke
Worldwide distribution in grazing and wild animals.
Acquired by eating metacercaria on leafy green plants (watercress)
F. Hepatica
Adults in bile ducts and liver tissue, but aberrant locations are seen. Severity of disease depends on number of worms.
Diagnosis: Eggs in feces, ultrasound of CT scan, ELISA
F. Hepatica
Common name: Giant intestinal fluke
Fasciolopsis buski
Giant intestinal fluke
Mostly found in SE Asia, India, and China
F. Buski
Adults in small intestine, causes diarrhea, bile duct and intestinal blockage with heavy infection.
Acquired through eating water plants with metacercaria. (fertilized with human feces)
Diagnosis: eggs or adults in feces
F. Buski
Common name: Chinese liver fluke
Clonorchis sinensis
Pathogenesis
Cirrhosis: Swelling of the bile ducts
Blockage of the bile passages
Cholangitis, pancreatitis, linked to cancer
Multiple infections: Up to 21,000
adults per hostClonorchis sinensis
Known as Chinese liver fluke
Distribution, mostly SE Asia, China, Russia
C. sinensis
Acquired by eating undercooked freshwater fish harboring metacercaria
Adults in bile ducts, cause blockage, swelling, destruction
Diagnosis: Eggs in feces, ELISA, CT
C. sinensis
Pathogenesis: Schistosomiasis also known as bilharzia (bilharziasis) or snail fever
Schistosoma spp.
Often termed Blood Flukes
Schistosoma spp
Adult:
Male: Flattened and rolled to form a gynecophoral groove; resembles a taco shell
Female: Slender and cylindrical, fits in the groove of the male
Color: Tan to gray
Testes: Number characteristic of species
Rejoined ceca: Length of reunited stem varies with species
Schistosoma spp
Common name: Oriental blood fluke
Schistosoma japonicum
Pathogenesis
**MOST pathogenic: Produces **MOST EGGS per day
Hepatic and pulmonary lesions
Central nervous system involvement
Schistosoma japonicum
Intermediate host: Fresh water snail (Oncomelania)
Reservoir host: Mammals exposed to contaminated water (cattle, pigs)
Infective form: Cercaria
Mode of infection: Active penetration
Schistosoma japonicum
Common name: Vesical blood fluke
Schistosoma haematobium
Pathogenesis
Urogenital tract involvement
Reduced bladder capacity, obstruction, hematuria, cancer
Geographic distribution: Africa, parts of Middle East
Habitat: Venules of urinary bladder surrounding organs are affected
Schistosoma haematobium
Intermediate host: Fresh water snail (Bulinus)
Infective form: Cercaria
Mode of infection: Active penetration
Schistosoma haematobium
Common name: Manson’s blood fluke
Schistosoma mansoni
Intermediate host: Fresh water snail (Biomphalaria)
Reservoir host: Primates, insectivores, wild rodents
Infective form: Cercaria
Mode of infection: Active penetration
Schistosoma mansoni
Eggs cause disease through obstruction, secreted antigens, cause fibrosis in various organs species dependent. Modulate immune response to Th2
Acquire through CERCARIAL skin penetration
Schistosomes
Diagnosis: eggs in feces or urine (species dependent), ELISA, ultrasound, biopsy
Schistosomes
Common name: Small intestinal fluke
Metagonimus yokogawai/Heterophyes heterophyes
Habitat: Small intestines Intermediate host First: Snail Second: Fish Reservoir host: Piscivores and birds Infective form: Metacercaria Mode of infection: Ingestion
Common in fish markets
Metagonimus yokogawai/Heterophyes heterophyes
Flukes of the small intestine, cause epigastric distress. Little damage unless heavily infected.
M. yokogawai and H. heterophyes
Acquired by eating the metacercaria just under the skin of undercooked freshwater fish (carp, salmon, mullet, tilapia)
Spread by using human feces as fertilizer.
M. yokogawai and H. heterophyes
Diagnosis: clinical, eggs in feces but too similar to differentiate.
M. yokogawai and H. heterophyes
Where are you most likely going to find Schistosoma haematobium eggs?
A. Feces
B. Blood
C. Urine
D. CSF
B. Blood
Which of these trematodes is considered the lung fluke?
A. Metagonimus yokogawai
B. Paragonimus westermani
C. Clonorchis sinensis
D. Diphyllobothrium latum
B. Paragonimus westermani
