Dr. Libman -- Parasitology 4: Trematodes and Cestodes Flashcards
What are trematodes commonly known as?
Flukes
Phylum under which cestodes and trematodes belong
Platyhelminthes
4 types of trematodes
- Schistosoma
- Opisthorchis
- Paragonimus
- Fasciola
Location of adult schistosoma
Human blood
Location of adult opisthorchis
Human liver
Location of adult paragonimus
Human lung
Location of adult fasciola
Human liver
Source of schistosoma
Water
Source of opisthorchis
Freshwater fish
2 sources of paragonimus
Freshwater crabs and cray fish
Source of fasciola
Watercress
Types of flukes that are hermaphroditic
Liver flukes, lung flukes, etc
Type of flukes that have two sexes
Blood flukes
Describe the general trematode life cycle (5 steps)
- Adult lives in human
- Lays egg
- Miracidium released
- Snail harbors redia/sporocysts
- Cercaria released and enters human through tissue (~2 days) OR metacercaria released into/onto fish, crabs and watercress
Describe the mating process of schistoma
Female lives inside the male and they mate for life while hugging
Location of schistosomule maturation
Portal veins near liver
Location of schistosoma eggs in human
Small venules of pelvic or mesenteric venous plexuses
Describe the fate of schistosoma eggs
Pass through tissue to lumen of bladder or colon (depends on location) and are voided
OR
Pass into venules and end up in liver
4 organisms of intestinal schistosomiasis
- S. mansoni
- S. japonicum
- S. intercalatum
- S. mekongi
Urinary schistosomiasis
S. hematobium
Distribution of S. hematobium (3)
- Sub-saharan africa
- Some middle east
- Madagascar
Geographic distribution of S. japonicum (2)
- Eastern China
- Southerm Japan
Geographic distribution of S. mansoni (4)
- Sub-saharan Africa
- Some middle east
- East coast of brazil
- Some Caribbean
Consequence of schistosomas eggs landing in liver as opposed to leaving the body
Portal fibrosis –> portal hypertension
4 types of clinical manifestations of intestinal schistosomiasis
- Portal hypertension
- Pulmonary hypertension
- CNS lesions
- Intestinal polyposis
4 manifestations of portal hypertension in intestinal schistosomiasis
- Splenomegaly
- Esophageal varices
- Hypersplenism
- Ascites
2 CNS lesions associated with intestinal schistosomiasis
- Spine = transverse myelitis
- Cerebral = seizures (S. japonicum)
3 manifestations of intestinal polyposis in intestinal schistosomiasis
- Both sessile and pedunculated contractures
- Intusseception
- Chronic salmonellosis
5 ways to diagnose intestinal schistosomiasis
- Stool ova
- Serology
- Large intestine
- Liver biopsy
- Ultrasound
Presentatino of urinary schistosomiasis (7)
- Hematuria (terminal)
- Urinry frequency
- Pyuria
- Pyelonephritis
- Obstructive uropathy
- Cancer of bladder (squamous cell)
- Distant metastases (spinal column; pulmonary HTN)
5 ways to diagnose urinary schistosomiasis
- Debris in urine
- Eggs in urine (overnight-millipore)
- IVP abnormalities
- Cystoscopy
- Serology